Patent Publication Number: US-2021185103-A1

Title: Personal media streaming appliance system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 15/973,198, filed 7 May 2018, the disclosure of which is hereby incorporated by reference in its entirety. To the extent appropriate, a claim of priority is made to the above disclosed application. 
    
    
     BACKGROUND 
     Many people enjoy consuming media content while travelling or during other activities. For example, many drivers and passengers listen to audio content, such as songs, albums, podcasts, audiobooks, and other types of audible content, in vehicles. Typical sources of such audio content in vehicles include radios and fixed media players, such as devices that can play media content from CDs, USB drives, or SD cards. Media content from such typical sources is not flexible or personalized for the listeners in vehicles. 
     Alternatively, mobile devices, such as mobile phones or tablets running audio streaming applications, can offer a personalized and flexible music-consuming experience using large catalogs of media content available from a media content server. However, mobile devices are not well suited for a vehicle environment for various reasons, such as legal restrictions and sophisticated user interfaces that are not convenient for use in a vehicle. 
     There exists a need for a media playback system that is easy to use and control for media content playback while providing personalized user experience of consuming media content in a vehicle. 
     SUMMARY 
     In general terms, the present disclosure relates to a personal media streaming appliance system. In one possible configuration and by non-limiting example, the system is configured to stream personalized media content for playback in a vehicle. Various aspects are described in this disclosure, which include, but are not limited to, the following aspects. 
     One aspect is a personal appliance system for streaming media content for playback by a vehicle media playback system of a vehicle. The system include a docking device and a personal media streaming appliance. The docking device has an appliance coupling structure and a vehicle mounting portion. The vehicle mounting portion is arranged opposite to the appliance coupling structure and configured to mount the docking device to the vehicle. The personal media streaming appliance includes a body, a dock mounting structure, at least one processing device, at least one data storage device, a manual user interface system, a cellular-based media streaming system, a noise-cancelling voice interaction system, and an appliance operation system. The body defines an interior space and has a front side and an opposite rear side. The dock mounting structure is arranged on the rear side and configured to engage the appliance coupling structure of the docking device. The at least one processing device is contained in the interior space of the body. The at least one data storage device is contained in the interior space of the body and stores data instructions executable by the at least one processing device. The manual user interface system is configured to receive manual user input for controlling playback of media content. The user interface system includes a rotatable manual control knob assembly arranged at the front side of the body, and a plurality of depressible preset button assemblies. The at least one data storage device includes a manual input processing engine configured to detect the manual user input and control playback of the media content based on the manual user input. The cellular-based media streaming system includes a wireless data communication device configured to communicate with a media content provider via a cellular network. The noise-cancelling voice interaction system includes at least one microphone configured to detect sounds in the vehicle. The at least one data storage device includes a sound processing engine that operates to identify a voice input from the detected sounds in the vehicle, and a voice interaction engine that operates to cooperate with the media content provider to determine a command intended by the voice input. The appliance operation system includes a power input device and a media content output interface. The power input device is configured to be electrically connected to a power source of the vehicle and receive electric power from the vehicle. The at least one data storage device includes a media content processing engine that operates to process the media content and generate and transmit through the media content output interface a media content signal that is usable by the vehicle media playback system for playback of the media content. 
     In certain example, in the cellular-based media streaming system, the at least one data storage device includes at least one of a device identifier and a user account identifier. The device identifier identifies the personal media streaming appliance, and the user account identifier identifies a user of the media content provider. The at least one data storage device further includes a wireless data communication engine that operates to transmit at least one of the device identifier and the user account identifier to the media content provider and receive media content associated with the at least one of the device identifier and the user account identifier from the media content provider at least partially via the cellular network. 
     In certain examples, the appliance operation system further includes an appliance activation engine that is automatically activated by the at least one processing device upon powering up the personal media streaming appliance, the appliance activation engine configured to at least partially operates at least one of the other engines upon activation. 
     In certain examples, the appliance activation engine continues running until the personal media streaming appliance is powered down below a predetermined power level. 
     In certain examples, the personal media streaming appliance is free of user interface controls that would allow a user to disable operation of the appliance activation engine on the personal media streaming appliance. 
     In certain examples, the appliance operation system further includes a battery and a power management engine. The battery is incorporated in the interior space of the body. The power management engine is configured to charge the battery with the electric power received from the power source of the vehicle through the power input device. 
     In certain examples, the media content provider includes a media content source. 
     In certain examples, the personal media streaming appliance further includes a display device arranged on the manual control knob assembly and configured to display information relating to the playback of the media content. 
     In certain examples, the manual control knob assembly is manually operable in a plurality of movements relative to the body. The plurality of movements corresponds to a plurality of manual inputs. In certain examples, the plurality of movements includes a rotational movement of at least a portion of the manual control knob assembly relative to the body. 
     In certain examples, the dock mounting structure of the personal media streaming appliance is constructed to have a non-circular profile. In certain examples, the dock mounting structure of the personal media streaming appliance includes a recessed portion provided on the rear side of the body. The recessed portion has a non-circular profile. 
     In certain examples, the appliance coupling structure of the docking device is constructed to complementarily engage the non-circular profile of the dock mounting structure of the personal media streaming appliance, thereby forming a mechanical interface therebetween configured to resist a rotational force applied by a user upon a rotation of the manual control knob assembly. In certain examples, the appliance coupling structure of the docking device includes a protruded portion, the protruded portion having a non-circular profile that is complementary to the recessed portion. 
     In certain examples, the personal media streaming appliance further includes a plurality of appliance connectors provided in the dock mounting structure. 
     In certain examples, the docking device includes a dock body, a plurality of dock connectors, a power source input device, and a media signal output device. The plurality of dock connectors are provided in the appliance coupling structure and arranged to align with the plurality of appliance connectors and connect with the plurality of appliance connectors when the appliance coupling structure engages with the dock mounting structure. The power source input device is configured to be electrically connected to the power source of the vehicle. The power source input device is configured to receive the electric power from the vehicle and transmit the electric power to the power input device of the personal media streaming appliance. The media signal output device is configured to be connected to the vehicle media playback system. The media signal output device is configured to receive the media content from the personal media streaming appliance through the media content output interface and transmit the media content to the vehicle media playback system. 
     In certain examples, the dock mounting structure of the personal media streaming appliance includes an appliance magnetic attachment device included in the interior space of the body and arranged adjacent the rear side of the body. In certain examples, the appliance magnetic attachment device includes one or more first magnetic plates with a polarity, and one or more second magnetic plates with an opposite polarity. 
     In certain examples, the docking device further includes a dock magnetic attachment device including in the dock body and configured to interact with the appliance magnetic attachment device to removably secure the appliance coupling portion to the dock coupling portion. In certain examples, the dock magnetic attachment includes one or more first magnets and one or more second magnets. The first magnets are configured to attract the first magnetic plates of the personal media streaming appliance, and the second magnets are configured to attract the second magnetic plates of the personal media streaming appliance. In certain examples, at least one of the first magnets and at least one of the second magnets are alternately arranged. 
     In certain examples, at least one of the power source input device and the media signal output device is configured with at least one of a USB cable and an auxiliary cable. 
     In certain examples, the plurality of appliance connectors includes a power input connector configured to receive power from the docking device, and a media signal output connector configured to transmit media content. 
     In certain examples, the plurality of dock connectors includes a power output connector and a media signal input connector. The power output connector is connected to the power source input device of the docking device. The power output connector is arranged to connect with the power input connector of the appliance and configured to provide power to the appliance. The media signal input connector is arranged to connect with the media signal output connector of the appliance, and configured to receive the media content from the appliance and transmit the media content to the vehicle media playback system via the media signal output device. 
     In certain examples, the plurality of appliance connectors includes a first docking status identification connector. The plurality of dock connectors includes a second docking status identification connector arranged to connect with the first docking status identification connector to determine that the appliance is mounted to the docking device in a predetermined configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example system for streaming media content for playback. 
         FIG. 2  is a block diagram of an example embodiment of a personal media streaming appliance (PMSA) system. 
         FIG. 3  is a block diagram of an example embodiment of a media delivery system. 
         FIG. 4  is a block diagram of an example embodiment of a vehicle media playback system. 
         FIG. 5  is a block diagram of an example embodiment of a mobile computing device. 
         FIG. 6  schematically illustrates an example embodiment of the PMSA system. 
         FIG. 7  is a block diagram of an example embodiment of a personal media steaming appliance (PMSA). 
         FIG. 8  illustrates an example data structure of local data. 
         FIG. 9  illustrates an example request signal. 
         FIG. 10  is a front perspective view of an example embodiment of the PMSA. 
         FIG. 11  is a rear perspective view of the PMSA of  FIG. 10 . 
         FIG. 12  is an exploded rear perspective view of the PMSA of  FIG. 1 . 
         FIG. 13  is another exploded rear perspective view of the PMSA of  FIG. 1 . 
         FIG. 14  is a front perspective view of an example docking device. 
         FIG. 15  is a rear perspective view of the docking device of  FIG. 14 . 
         FIG. 16  is an exploded rear perspective view of the docking device of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. 
     People spend a significant amount of time travelling in vehicles. Many of them find that time to be more enjoyable when they are listening to music, watching videos, or otherwise consuming media content. Media content includes audio and video content. Examples of audio content include songs, albums, playlists, radio stations, podcasts, audiobooks, and other audible media content items. Examples of video content include movies, music videos, television programs, and other visible media content items. In many cases, video content also includes audio content. As used herein, the term “vehicle” can be any machine that is operable to transport people or cargo. Vehicles can be motorized or non-motorized. Vehicles can be for public or private transport. Examples of vehicles include motor vehicles (e.g., cars, trucks, buses, and motorcycles), rail vehicles (e.g., trains, trams), tracked vehicles, watercraft (e.g., ships, boats), aircraft, human-powered vehicles (e.g., bicycles), wagons, and other transportation means. A user can drive a vehicle or ride in as a passenger for travelling. As used herein, the term “travel” and variants thereof refers to any activity in which a user is in transit between two locations. 
     Consuming media content in a vehicle presents many challenges. In general, a user in a moving vehicle may have limited attention available for interacting with a media playback device due to the need to concentrate on travel related activities, such as driving and navigation. Therefore, while a vehicle is moving, it can be difficult for a user in the vehicle to interact with a media playback device without disrupting the driving or navigation. Further, the user interface of a media playback device can be overly complex, or may require such fine motor skills that it can be difficult to use while traveling in a vehicle. Voice-based user interfaces also encounter significant challenges to use in a vehicle environment. The passenger areas of a vehicle are often noisy due to engine noise, road noise, wind and weather noises, passenger noises, and the sound of any media content that may be playing on a media playback system in the vehicle. This noise hampers the ability of the voice-based user interface to interact with a user. Moreover, accessing media content while travelling may be difficult, expensive, or impossible depending on network availability or capacity along the route of travel. Further, accessing and playing media content can require significant amounts of electric power. Thus, use of a mobile device for media content playback during travel may be undesirable because it will drain the battery. It can also be challenging to connect a media playback device to a vehicle&#39;s built-in audio system because of the requirement to connect to auxiliary cables or undergo a complicated wireless pairing process. Embodiments disclosed herein address some or all of these challenges. It should be understood, however, that various aspects described herein are not limited to use of a media playback device during travel. 
     On the other hand, many users desire a personalized media consuming experience. For example, a user can access almost limitless catalogs of media content through various free or fee-based media delivery services, such as media streaming services. Users can use mobile devices or other media playback devices to access large catalogs of media content. Due to such large collections of media content, it is desired to make it possible to customize a selection of media content to match users&#39; individual tastes and preferences so that users can consume their favorite media content while traveling in a vehicle. 
     Many vehicles include a built-in media playback device, such as a radio or a fixed media player, such as a player that can play media content from a CD, USB driver, or SD cards. However, the media content that is delivered using these built in vehicle media playback devices is greatly limited and is not flexible or customizable to the user. 
     Alternatively, a mobile device, such as a smartphone or a tablet, can be used by a user to enjoy personalized and flexible music consuming experience in a vehicle by running music streaming applications thereon. However, mobile devices are not well suited for use in a vehicle environment for various reasons. For example, mobile devices are not readily accessible or controllable while driving or navigating. Further, connection between a mobile device and a vehicle audio system is often inconvenient and unreliable. Moreover, the music streaming application is not automatically ready to run and play media content, and the user needs to pick up the mobile device and open the music streaming application and control a sophisticated user interface to play media content. Additionally, many users have limited mobile data available via their mobile devices and are concerned about data usage while using the music streaming application in the vehicle. Battery drainage and legal restrictions on use while driving are further drawbacks to using mobile devices for playing media content in the vehicle. 
     To address these challenges, the present disclosure provides a special-purpose personal appliance that can be used for streaming media in a vehicle. In some embodiments, the appliance is specially designed to be dedicated for media streaming purposes in a vehicle, and there is no other general use. Some embodiments of the appliance can operate to communicate directly with a media content server and receive streamed media content from the server via a cellular network. In these embodiments, other computing devices, such as mobile devices, are not involved in this direct communication between the appliance and the media content server. Mobile data cost can be included in the subscription of the media streaming service or a purchase price of the personal appliance. Therefore, the customer&#39;s possible concern about mobile data usage can be eliminated. In other embodiments, the appliance can connect to another computing device, such as a mobile device, that provides a mobile hotspot to enable the appliance to communicate with the media content server rather than the appliance communicating with it directly. For example, a mobile device is used to assist in communication between the appliance and the media content server. 
     Further, the appliance can be associated with a user account of the user for the media streaming service so that the user can enjoy personalized media content. 
     In some embodiments, the appliance provides a simplified user interface so that a user can easily control playback of media content in a vehicle while maintaining his or her focus on other tasks such as driving or navigating. For example, the appliance has a limited set of physical control elements that are intuitively controllable for playback of media content with little (often only one) input from a user. Examples of such physical control elements include a rotatable knob and one or more physically-depressible buttons. 
     Further, in some embodiments, the appliance is configured to be easily mounted to an interior structure of a vehicle, such as a dashboard, so that the user can easily reach the appliance. 
     In some embodiments, the appliance also provides an output interface that can be easily connected to a vehicle audio system, such as via an auxiliary input port, Bluetooth, or an FM transmitter. Therefore, the media content streamed to the appliance can then be transmitted from the appliance to the vehicle audio system for playback in the vehicle. 
     In some embodiments, the appliance can include a voice interaction system designed for voice interaction with a user in the noisy environment of a vehicle. In some embodiments, the appliance includes multiple microphones that reduce the effects of ambient noise in the passenger area of the vehicle. In an example, the appliance includes at least three microphones: two directed to the passenger area of the vehicle and another facing away from the passenger area of the vehicle to pick up vibrations and low frequency noise for cancellation. The appliance also applies spectral noise cancellation to reduce non-voice frequencies. In addition, omni-directional noise cancellation is applied in some embodiments to reduce omni-directional sound (e.g., vehicle noise). Directional noise is detected by determining a difference between audio inputs detected by the two microphones facing the passenger area. The difference is preserved as directional audio input. The appliance further cancels out audio that it is currently playing, allowing the appliance to detect voice commands even over loud music, for instance. In this manner, the appliance is arranged to provide an improved voice-based interface in a vehicle environment. 
     As described herein, consuming media content may include one or more of listening to audio content, watching video content, or consuming other types of media content. For ease of explanation, the embodiments described in this application are presented using specific examples. For example, audio content (and in particular music) is described as an example of one form of media consumption. As another example, a vehicle is described as an example of an environment in which media content is consumed. Further, traveling (and in particular driving) in a vehicle is described as an example of an activity during which media content is consumed. 
     However, it should be understood that the same concepts are similarly applicable to other forms of media consumption and to other environments or activities, and at least some embodiments include other forms of media consumption and/or are configured for use in other environments or during other activities. 
       FIG. 1  illustrates an example system  100  for streaming media content for playback. The system  100  can be used in a vehicle  80 . The vehicle  80  includes a dashboard  82  or a head unit  84 . The system  100  includes one or more media playback devices  104  configured to play media content, such as a personal media streaming appliance (PMSA) system  110 , a media delivery system  112 , a vehicle media playback system  114 , and a mobile computing device  118 . The system  100  further includes a data communication network  116  and an in-vehicle wireless data communication network  122 . 
     The PMSA system  110  operates to receive media content that is provided (e.g., streamed, transmitted, etc.) by a system external to the PMSA system  110 , such as the media delivery system  112 , and transmit the media content to the vehicle media playback system  114  for playback. In some embodiments, the PMSA system  110  is a portable device which can be carried into and used in the vehicle  80 . The PMSA system  110  can be mounted to a structure of the vehicle  80 , such as the dashboard  82  or the head unit  84 . In other embodiments, the PMSA system  110  can be configured to be built in a structure of the vehicle  80 . An example of the PMSA system  110  is illustrated and described in more detail with reference to  FIGS. 2 and 6 . 
     The media delivery system  112  operates to provide media content to one or more media playback devices  104  via the network  116 . In the illustrated example, the media delivery system  112  provides media content to the PMSA system  110  for playback of media content using the vehicle media playback system  114 . An example of the media delivery system  112  is illustrated and described in further detail herein, such as with reference to  FIG. 3 . 
     The vehicle media playback system  114  operates to receive media content from the PMSA system  110  and generates a media output  124  to play the media content in the vehicle  80 . An example of the vehicle media playback system  114  is illustrated and described in further detail herein, such as with reference to  FIG. 4 . 
     The network  116  is a data communication network that facilitates data communication between the PMSA system  110  and the media delivery system  112 . In some embodiments, the mobile computing device  118  can also communicate with the media delivery system  112  across the network  116 . The network  116  typically includes a set of computing devices and communication links between the computing devices. The computing devices in the network  116  use the links to enable communication among the computing devices in the network. The network  116  can include one or more routers, switches, mobile access points, bridges, hubs, intrusion detection devices, storage devices, standalone server devices, blade server devices, sensors, desktop computers, firewall devices, laptop computers, handheld computers, mobile telephones, vehicular computing devices, and other types of computing devices. 
     In various embodiments, the network  116  includes various types of communication links. For example, the network  116  can include wired and/or wireless links, including cellular, Bluetooth, ultra-wideband (UWB), 802.11, ZigBee, and other types of wireless links. Furthermore, in various embodiments, the network  116  is implemented at various scales. For example, the network  116  can be implemented as one or more vehicle area networks, local area networks (LANs), metropolitan area networks, subnets, wide area networks (WAN) (such as the Internet), or can be implemented at another scale. Further, in some embodiments, the network  116  includes multiple networks, which may be of the same type or of multiple different types. 
     In some embodiments, the network  116  can also be used for data communication between other media playback devices  104  (e.g., the mobile computing device  118 ) and the media delivery system  112 . Because the network  116  is configured primarily for data communication between computing devices in the vehicle  80  and computing devices outside the vehicle  80 , the network  116  is also referred to herein as an out-of-vehicle network for out-of-vehicle data communication. 
     Unlike the network  116 , the in-vehicle wireless data communication  122  can be used for direct data communication between computing devices (e.g., the media playback devices  104 ) in the vehicle  80 . In some embodiments, the in-vehicle wireless data communication  122  is used for direct communication between the PMSA system  110  and the mobile computing device  118 . In other embodiments, the mobile computing device  118  can communicate with the PMSA system  110  in the data communication network  116 . In some embodiments, the in-vehicle wireless data communication  122  can also be used for data communication between the PMSA system  110  and the vehicle media playback system  114 . 
     Various types of wireless communication interfaces can be used for the in-vehicle wireless data communication  122 . In some embodiments, the in-vehicle wireless data communication  122  includes Bluetooth® technology. In other embodiments, the in-vehicle wireless data communication  122  includes WiFi® technology. In yet other embodiments, other suitable wireless communication interfaces can be used for the in-vehicle wireless data communication  122 , such as near field communication (NFC) and an ultrasonic data transmission. 
     In some embodiments, the mobile computing device  118  is configured to play media content independently from the PMSA system  110 . In some embodiments, the mobile computing device  118  is a standalone computing device that, without the PMSA system  110  involved, can communicate with the media delivery system  112  and receive media content from the media delivery system  112  for playback in the vehicle  80 . An example of the mobile computing device  118  is illustrated and described in further detail herein, such as with reference to  FIG. 5 . 
       FIG. 2  is a block diagram of an example embodiment of the PMSA system  110  of the media streaming system  100  shown in  FIG. 1 . In this example, the PMSA system  110  includes a user input device  130 , a display device  132 , a wireless data communication device  134 , a movement detection device  136 , a location determining device  138 , a media content output device  140 , an in-vehicle wireless communication device  142 , a power supply device  144 , a power input device  146 , a processing device  148 , and a memory device  150 . 
     In some embodiments, the PMSA system  110  is a system dedicated for streaming personalized media content in a vehicle environment. At least some embodiments of the PMSA system  110  have limited functionalities specifically selected for streaming media content from the media delivery system  112  at least via the network  116  and/or for providing other services associated with the media content streaming service. The PMSA system  110  may have no other general use such as found in other computing devices, such as smartphones, tablets, and other smart devices. For example, in some embodiments, when the PMSA system  110  is powered up, the PMSA system  110  is configured to automatically activate a software application that is configured to perform the media content streaming and media playback operations of the PMSA system  110  using at least one of the components, devices, and elements of the PMSA system  110 . In some embodiments, the software application of the PMSA system  110  is configured to continue running until the PMSA system  110  is powered off or powered down to a predetermined level. In some embodiments, the software application is provided by the media content provider. In some embodiments, the PMSA system  110  is configured to be free of any user interface control that would allow a user to disable the automatic activation of the software application on the PMSA system  110 . 
     As described herein, the PMSA system  110  provides various structures, features, and functions that improve the user experience of consuming media content in a vehicle. 
     As illustrated, the PMSA system  110  can communicate with the media delivery system  112  to receive media content via the network  116  and enable the vehicle media playback system  114  to play the media content in the vehicle. In some embodiments, the PMSA system  110  can communicate with the mobile computing device  118  that is in data communication with the media delivery system  112 . As described herein, the mobile computing device  118  can communicate with the media delivery system  112  via the network  116 . 
     The user input device  130  operates to receive a user input  152  from a user U for controlling the PMSA system  110 . As illustrated, the user input  152  can include a manual input  154  and a voice input  156 . In some embodiments, the user input device  130  includes a manual input device  160  and a sound detection device  162 . 
     The manual input device  160  operates to receive the manual input  154  for controlling playback of media content via the PMSA system  110 . In addition, in some embodiments, the manual input  154  is received for managing various pieces of information transmitted via the PMSA system  110  and/or controlling other functions or aspects associated with the PMSA system  110 . 
     In some embodiments, the manual input device  160  includes one or more manual control elements configured to receive various manual control actions, such as pressing actions and rotational actions. As described herein, the physical input device  160  includes a manual control knob assembly  510  and one or more physical button assemblies  512 , which is further illustrated and described with reference to  FIG. 6 . 
     The sound detection device  162  operates to detect and record sounds from proximate the PMSA system  110 . For example, the sound detection device  162  can detect sounds including the voice input  156 . In some embodiments, the sound detection device  162  includes one or more acoustic sensors configured to detect sounds proximate the PMSA system  110 . For example, acoustic sensors of the sound detection device  162  include one or more microphones. Various types of microphones can be used for the sound detection device  162  of the PMSA system  110 . 
     In some embodiments, the voice input  156  is a user&#39;s voice (also referred to herein as an utterance) for controlling playback of media content via the PMSA system  110 . In addition, the voice input  156  is a user&#39;s voice for managing various data transmitted via the PMSA system  110  and/or controlling other functions or aspects associated with the PMSA system  110 . 
     In some embodiments, the sound detection device  162  is configured to cancel noises from the received sounds so that a desired sound (e.g., the voice input  156 ) is clearly identified. For example, the sound detection device  162  can include one or more noise-canceling microphones which are configured to filter ambient noise from the voice input  156 . In addition or alternatively, a plurality of microphones of the sound detection device  162  are arranged at different locations in a body of the PMSA system  110  and/or oriented in different directions with respect to the body of the PMSA system  110 , so that ambient noise is effectively canceled from the voice input  156  or other desired sounds being identified. 
     In some embodiments, the sounds detected by the sound detection device  162  can be processed by the sound processing engine  180  of the PMSA system  110  as described below. 
     Referring still to  FIG. 2 , the display device  132  operates to display information to the user U. Examples of such information include media content playback information, notifications, and other information. 
     In some embodiments, the display device  132  operates as a display screen only and is not capable of receiving a user input. By receiving the manual input  154  only via the manual input device  160  and disabling receipt of manual input via the display device  132 , the user interface of the PMSA system  110  is simplified so that the user U can control the PMSA system  110  while maintaining focus on other activities in the vehicle  80 . It is understood however that, in other embodiments, the display device  132  is configured as a touch-sensitive display screen that operates as both a display screen and a user input device. In yet other embodiments, the PMSA system  110  does not include a display device. 
     As described herein, in some embodiments, the display device  132  is arranged at the manual input device  160 . In other embodiments, the display device  132  is arranged separate from the manual input device  160 . 
     The wireless data communication device  134  operates to enable the PMSA system  110  to communicate with one or more computing devices at a remote location that is outside the vehicle  80 . In the illustrated example, the wireless data communication device  134  operates to connect the PMSA system  110  to one or more networks outside the vehicle  80 , such as the network  116 . For example, the wireless data communication device  134  is configured to communicate with the media delivery system  112  and receive media content from the media delivery system  112  at least partially via the network  116 . The wireless data communication device  134  can be a wireless network interface of various types which connects the PMSA system  110  to the network  116 . Examples of the wireless data communication device  134  include wireless wide area network (WWAN) interfaces, which use mobile telecommunication cellular network technologies. Examples of cellular network technologies include LTE, WiMAX, UMTS, CDMA2000, GSM, cellular digital packet data (CDPD), and Mobitex. In some embodiments, the wireless data communication device  134  is configured as a cellular network interface to facilitate data communication between the PMSA system  110  and the media delivery system  112  over cellular network. 
     The movement detection device  136  can be used to detect movement of the PMSA system  110  and the vehicle  80 . In some embodiments, the movement detection device  136  is configured to monitor one or more factors that are used to determine movement of the vehicle  80 . The movement detection device  136  can include one or more sensors that are configured to detect movement, position, and/or orientation of the PMSA system  110 . As an example, the movement detection device  136  is operable to determine an orientation of the PMSA system  110 . The movement detection device  136  can detect changes in the determined orientation and interpret those changes as indicating movement of the PMSA system  110 . In some embodiments, the movement detection device  136  includes an accelerometer. In other embodiments, the movement detection device  136  includes a gyroscope. Other sensors can also be used for the movement detection device  136 , such as a magnetometer, a GPS receiver, an altimeter, an odometer, a speedometer, a shock detector, a vibration sensor, a proximity sensor, and an optical sensor (e.g., a light sensor, a camera, and an infrared sensor). 
     The location determining device  138  is a device that determines the location of the PMSA system  110 . In some embodiments, the location determining device  138  uses one or more of Global Positioning System (GPS) technology (which may receive GPS signals), Global Navigation Satellite System (GLONASS), cellular triangulation technology, network-based location identification technology, Wi-Fi positioning systems technology, and combinations thereof. 
     The media content output device  140  is an interface that enables the PMSA system  110  to transmit media content to the vehicle media playback device  114 . Some embodiments of the PMSA system  110  do not have a speaker and thus cannot play media content independently. In these embodiments, the PMSA system  110  is not regarded as a standalone device for playing media content. Instead, the PMSA system  110  transmits media content to another media playback device, such as the vehicle media playback device  114  to enable the other media playback device to play the media content, such as through the vehicle stereo system. 
     As illustrated, the PMSA system  110  (e.g., a media content processing engine  176  thereof in  FIG. 2 ) can convert media content to a media content signal  164 , the media content output device  140  transmits the media content signal  164  to the vehicle media playback system  114 . The vehicle media playback system  114  can play the media content based on the media content signal  164 . For example, the vehicle media playback system  114  operates to convert the media content signal  164  into a format that is readable by the vehicle media playback system  114  for playback. 
     In some embodiments, the media content output device  140  includes an auxiliary (AUX) output interface  166  and a wireless output interface  168 . 
     The AUX output interface  166  is configured to connect the PMSA system  110  to the vehicle media playback system  114  via a cable (e.g., a media content output line  550  in  FIG. 6 ) of the PMSA system  110 . In some embodiments, as illustrated in  FIG. 6 , the media content output line  550  extending from the PMSA system  110  is connected to an input connector  340  (e.g., an auxiliary input jack or port) of the vehicle media playback system  114 . As illustrated herein, the media content output line  550  can be of various types, such as an analog audio cable or a USB cable. 
     The wireless output interface  168  is configured to connect the PMSA system  110  to the vehicle media playback system  114  via a wireless communication protocol. In some embodiments, the wireless output interface  168  is configured for Bluetooth connection. In other embodiments, the wireless output interface  168  is configured for other types of wireless connection. In some embodiments, the wireless output interface  168  is incorporated into, or implemented with, the in-vehicle wireless communication device  142 . For example, when the media content output device  140  wirelessly transmits media content to the vehicle media playback system  114 , the in-vehicle wireless communication device  142  can be used to implement the wireless output interface  168  of the media content output device  140 . 
     Referring still to  FIG. 2 , the in-vehicle wireless communication device  142  operates to establish a wireless data communication, such as the in-vehicle wireless data communication  122 , between computing devices in a vehicle  80 . In the illustrated example, the in-vehicle wireless communication device  142  is used to enable the PMSA system  110  to communicate with other computing devices, such as the mobile computing device  118 , in the vehicle  80 . Various types of wireless communication interfaces can be used for the in-vehicle wireless communication device  142 , such as Bluetooth technology WiFi® technology, a near field communication (NFC), and an ultrasound data transmission. The in-vehicle wireless communication is also referred to herein as a short-range wireless communication. 
     The power supply device  144  is included in the example PMSA system  110  and is configured to supply electric power to the PMSA system  110 . In some embodiments, the power supply device  144  includes at least one battery. The power supply device  144  can be rechargeable. For example, the power supply device  144  can be recharged using the power input device  146  that is connected to an external power supply. In some embodiments, the power supply device  144  is included inside the PMSA system  110  and is not removable from the PMSA system  110 . In other embodiments, the power supply device  144  is removable by the user from the PMSA system  110 . 
     The power input device  146  is configured to receive electric power to maintain activation of components of the PMSA system  110 . As described herein, the power input device  146  is connected to a power source of the vehicle  80  (e.g., a vehicle power supply  540  in  FIG. 6 ) and uses the electric power from the vehicle  80  as a primary power source to maintain activation of the PMSA system  110  over an extended period of time, such as longer than several minutes. 
     The processing device  148 , in some embodiments, comprises one or more central processing units (CPU). In other embodiments, the processing device  148  additionally or alternatively includes one or more digital signal processors, field-programmable gate arrays, or other electronic circuits. 
     The memory device  150  typically includes at least some form of computer-readable media. The memory device  150  can include at least one data storage device. Computer readable media includes any available media that can be accessed by the PMSA system  110 . By way of example, computer-readable media includes computer readable storage media and computer readable communication media. 
     Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any device configured to store information such as computer readable instructions, data structures, program modules, or other data. Computer readable storage media includes, but is not limited to, random access memory, read only memory, electrically erasable programmable read only memory, flash memory and other memory technology, compact disc read only memory, blue ray discs, digital versatile discs or other optical storage, magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the PMSA system  110 . In some embodiments, computer readable storage media is non-transitory computer readable storage media. 
     Computer readable communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” refers to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, computer readable communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared, and other wireless media. Combinations of any of the above are also included within the scope of computer readable media. 
     The memory device  150  operates to store data and instructions. In some embodiments, the memory device  150  stores instructions for a media content cache  172 , a caching management engine  174 , a media content processing engine  176 , a manual input processing engine  178 , a sound processing engine  180 , a voice interaction engine  182 , a wireless data communication engine  184 , and a power management engine  186 . 
     Some embodiments of the memory device  150  include the media content cache  172 . The media content cache  172  stores media content items, such as media content items that have been received from the media delivery system  112 . The media content items stored in the media content cache  172  may be stored in an encrypted or unencrypted format. In some embodiments, the media content cache  172  also stores metadata about media content items such as title, artist name, album name, length, genre, mood, era, etc. The media content cache  172  can further store playback information about the media content items and/or other information associated with the media content items. 
     The caching management engine  174  is configured to receive and cache media content in the media content cache  172  and manage the media content stored in the media content cache  172 . In some embodiments, when media content is streamed from the media delivery system  112 , the caching management engine  174  operates to cache at least a portion of the media content into the media content cache  172  so that at least a portion of the cached media content can be transmitted to the vehicle media playback system  114  for playback. In other embodiments, the caching management engine  174  operates to cache at least a portion of media content into the media content cache  172  while online so that the cached media content is retrieved for playback while the PMSA system  110  is offline. 
     The media content processing engine  176  is configured to process the media content that is received from the media delivery system  112 , and generate the media content signal  164  usable for the vehicle media playback system  114  to play the media content. The media content signal  164  is transmitted to the vehicle media playback system  114  using the media content output device  140 , and then decoded so that the vehicle media playback system  114  plays the media content in the vehicle  80 . 
     The manual input processing engine  178  operates to receive the manual input  154  via the manual input device  160 . In some embodiments, when the manual input device  160  is actuated (e.g., pressed or rotated) upon receiving the manual input  154 , the manual input device  160  generates an electric signal representative of the manual input  154 . The manual input processing engine  178  can process the electric signal and determine the user input (e.g., the user command or instruction) corresponding to the manual input  154  to the PMSA system  110 . In some embodiments, the manual input processing engine  178  can perform a function requested by the manual input  154 , such as controlling playback of media content. The manual input processing engine  178  can cause one or more other engines to perform the function associated with the manual input  154 . 
     The sound processing engine  180  is configured to receive sound signals obtained from the sound detection device  162  and process the sound signals to identify different sources of the sounds received via the sound detection device  162 . In some embodiments, the sound processing engine  180  operates to filter the user&#39;s voice input  156  from noises included in the detected sounds. Various noise cancellation technologies, such as active noise control or cancelling technologies or passive noise control or cancelling technologies, can be used to filter the voice input from ambient noise. In examples, the sound processing engine  180  filters out omni-directional noise and preserves directional noise (e.g., an audio input difference between two microphones) in audio input. In examples, the sound processing engine  180  removes frequencies above or below human speaking voice frequencies. In examples, the sound processing engine  180  subtracts audio output of the device from the audio input to filter out the audio content being provided by the device. (e.g., to reduce the need of the user to shout over playing music). In examples, the sound processing engine  180  performs echo cancellation. By using one or more of these techniques, the sound processing engine  180  provides sound processing customized for use in a vehicle environment. 
     In other embodiments, the sound processing engine  180  operates to process the received sound signals to identify the sources of particular sounds of the sound signals, such as people&#39;s conversation in the vehicle, the vehicle engine sound, or other ambient sounds associated with the vehicle. 
     In some embodiments, a recording of sounds captured using the sound detection device  162  can be analyzed using speech recognition technology to identify words spoken by the user. The words may be recognized as commands from the user that alter the playback of media content and/or other functions or aspects of the PMSA system  110 . In some embodiments, the words and/or the recordings may also be analyzed using natural language processing and/or intent recognition technology to determine appropriate actions to take based on the spoken words. Additionally or alternatively, the sound processing engine  180  may determine various sound properties about the sounds proximate the PMSA system  110  such as volume, dominant frequency or frequencies, etc. These sound properties may be used to make inferences about the environment proximate to the PMSA system  110 . 
     The voice interaction engine  182  operates to cooperate with the media delivery system  112  (e.g., a voice interaction server  204  thereof as illustrated in  FIG. 3 ) to identify a command (e.g., a user intent) that is conveyed by the voice input  156 . In some embodiments, the voice interaction engine  182  transmits the user&#39;s voice input  156  that is detected by the sound processing engine  180  to the media delivery system  112  so that the media delivery system  112  operates to determine a command intended by the voice input  156 . In other embodiments, at least some of the determination process of the command can be performed locally by the voice interaction engine  182 . 
     In addition, some embodiments of the voice interaction engine  182  can operate to cooperate with the media delivery system  112  (e.g., the voice interaction server  204  thereof) to provide a voice assistant that performs various voice-based interactions with the user, such as voice feedbacks, voice notifications, voice recommendations, and other voice-related interactions and services. 
     The wireless data communication engine  184  can interact with the wireless data communication device  134  and operate to transmit data to other computing devices, such as the media delivery system  112 , and receive data from such other computing devices, such as the media delivery system  112 , via the network  116 . In some embodiments, the wireless data communication engine  184  operates to transmit a device identifier of the PMSA system  110  and/or an user account identifier associated with the PMSA system  110  to the computing device (e.g., the media delivery system  112 ) with which the PMSA system  110  is communicating via the network  116 . The media delivery system  112  can use the device identifier and/or the user account identifier to perform a function requested by the PMSA system  110 , such as streaming media content requested by the PMSA system  110 . 
     The power management engine  186  can operate to receive electric power through the power input device  146 . The power management engine  186  can further operate to charge or recharge the power supply device  144  with the electric power received through the power input device  146 . 
     In some embodiments, the power management engine  186  operates to manage electric power consumption of the PMSA system  110 , and switch the PMSA system  110  into one of a plurality of power consumption modes (e.g., a full power mode or a low power mode (such as a sleep mode)) depending on the operation condition of the PMSA system  110 . 
       FIG. 3  is a block diagram of an example embodiment of the media delivery system  112  of  FIG. 1 . The media delivery system  112  includes a media content server  200 , a personal media streaming appliance (PMSA) server  202 , and a voice interaction server  204 . 
     The media delivery system  112  comprises one or more computing devices and provides media content to the PMSA system  110  and, in some embodiments, other media playback devices, such as the mobile computing device  118 , as well. In addition, the media delivery system  112  interacts with the PMSA system  110  to provide the PMSA system  110  with various functionalities. 
     In at least some embodiments, the media content server  200 , the PMSA server  202 , and the voice interaction server  204  are provided by separate computing devices. In other embodiments, the media content server  200 , the PMSA server  202 , and the voice interaction server  204  are provided by the same computing device(s). Further, in some embodiments, at least one of the media content server  200 , the PMSA server  202 , and the voice interaction server  204  is provided by multiple computing devices. For example, the media content server  200 , the PMSA server  202 , and the voice interaction server  204  may be provided by multiple redundant servers located in multiple geographic locations. 
     Although  FIG. 3  shows a single media content server  200 , a single PMSA server  202 , and a single voice interaction server  204 , some embodiments include multiple media servers, multiple PMSA servers, and/or multiple voice interaction servers. In these embodiments, each of the multiple media servers, multiple PMSA serves, and multiple voice interaction servers may be identical or similar to the media content server  200 , the PMSA server  202 , and the voice interaction server, respectively, as described herein, and may provide similar functionality with, for example, greater capacity and redundancy and/or services from multiple geographic locations. Alternatively, in these embodiments, some of the multiple media servers, the multiple PMSA servers, and/or the multiple voice interaction servers may perform specialized functions to provide specialized services. Various combinations thereof are possible as well. 
     The media content server  200  transmits stream media  210  ( FIG. 2 ) to media playback devices such as the PMSA system  110 . In some embodiments, the media content server  200  includes a media server application  212 , a processing device  214 , a memory device  216 , and a network access device  218 . The processing device  214  and the memory device  216  may be similar to the processing device  148  and the memory device  150 , respectively, which have each been previously described. Therefore, the description of the processing device  214  and the memory device  216  are omitted for brevity purposes. 
     The network access device  218  operates to communicate with other computing devices over one or more networks, such as the network  116 . Examples of the network access device include one or more wired network interfaces and wireless network interfaces. Examples of such wireless network interfaces of the network access device  218  include wireless wide area network (WWAN) interfaces (including cellular networks) and wireless local area network (WLANs) interfaces. In other examples, other types of wireless interfaces can be used for the network access device  218 . 
     In some embodiments, the media server application  212  is configured to stream media content, such as music or other audio, video, or other suitable forms of media content. The media server application  212  includes a media stream service  222 , a media application interface  224 , and a media data store  226 . The media stream service  222  operates to buffer media content, such as media content items  230 A,  230 B, and  230 N (collectively  230 ), for streaming to one or more streams  232 A,  232 B, and  232 N (collectively  232 ). 
     The media application interface  224  can receive requests or other communication from media playback devices or other systems, such as the PMSA system  110 , to retrieve media content items from the media content server  200 . For example, in  FIG. 3 , the media application interface  224  receives communication from the PMSA system  110 , such as the caching management engine  174  thereof, to receive media content from the media content server  200 . 
     In some embodiments, the media data store  226  stores media content items  234 , media content metadata  236 , media contexts  238 , user accounts  240 , and taste profiles  242 . The media data store  226  may comprise one or more databases and file systems. Other embodiments are possible as well. 
     As discussed herein, the media content items  234  (including the media content items  230 ) may be audio, video, or any other type of media content, which may be stored in any format for storing media content. 
     The media content metadata  236  provides various information associated with the media content items  234 . In some embodiments, the media content metadata  236  includes one or more of title, artist name, album name, length, genre, mood, era, etc. 
     The media content metadata  236  operates to provide various pieces of information associated with the media content items  234 . In some embodiments, the media content metadata  236  includes one or more of title, artist name, album name, length, genre, mood, era, etc. 
     In some embodiments, the media content metadata  236  includes acoustic metadata, cultural metadata, and explicit metadata. The acoustic metadata may be derived from analysis of the track and refers to a numerical or mathematical representation of the sound of a track. Acoustic metadata may include temporal information such as tempo, rhythm, beats, downbeats, tatums, patterns, sections, or other structures. Acoustic metadata may also include spectral information such as melody, pitch, harmony, timbre, chroma, loudness, vocalness, or other possible features. Acoustic metadata may take the form of one or more vectors, matrices, lists, tables, and other data structures. Acoustic metadata may be derived from analysis of the music signal. One form of acoustic metadata, commonly termed an acoustic fingerprint, may uniquely identify a specific track. Other forms of acoustic metadata may be formed by compressing the content of a track while retaining some or all of its musical characteristics. 
     The cultural metadata refers to text-based information describing listeners&#39; reactions to a track or song, such as styles, genres, moods, themes, similar artists and/or songs, rankings, etc. Cultural metadata may be derived from expert opinion such as music reviews or classification of music into genres. Cultural metadata may be derived from listeners through websites, chatrooms, blogs, surveys, and the like. Cultural metadata may include sales data, shared collections, lists of favorite songs, and any text information that may be used to describe, rank, or interpret music. Cultural metadata may also be generated by a community of listeners and automatically retrieved from Internet sites, chat rooms, blogs, and the like. Cultural metadata may take the form of one or more vectors, matrices, lists, tables, and other data structures. A form of cultural metadata particularly useful for comparing music is a description vector. A description vector is a multi-dimensional vector associated with a track, album, or artist. Each term of the description vector indicates the probability that a corresponding word or phrase would be used to describe the associated track, album or artist. 
     The explicit metadata refers to factual or explicit information relating to music. Explicit metadata may include album and song titles, artist and composer names, other credits, album cover art, publisher name and product number, and other information. Explicit metadata is generally not derived from the music itself or from the reactions or opinions of listeners. 
     At least some of the metadata  236 , such as explicit metadata (names, credits, product numbers, etc.) and cultural metadata (styles, genres, moods, themes, similar artists and/or songs, rankings, etc.), for a large library of songs or tracks can be evaluated and provided by one or more third party service providers. Acoustic and cultural metadata may take the form of parameters, lists, matrices, vectors, and other data structures. Acoustic and cultural metadata may be stored as XML files, for example, or any other appropriate file type. Explicit metadata may include numerical, text, pictorial, and other information. Explicit metadata may also be stored in an XML or other file. All or portions of the metadata may be stored in separate files associated with specific tracks. All or portions of the metadata, such as acoustic fingerprints and/or description vectors, may be stored in a searchable data structure, such as a k-D tree or other database format. 
     Referring still to  FIG. 3 , each of the media contexts  238  is used to identify one or more media content items  234 . In some embodiments, the media contexts  238  are configured to group one or more media content items  234  and provide a particular context to the group of media content items  234 . Some examples of the media contexts  238  include albums, artists, playlists, and individual media content items. By way of example, where a media context  238  is an album, the media context  238  can represent that the media content items  234  identified by the media context  238  are associated with that album. 
     As described above, the media contexts  238  can include playlists  239 . The playlists  239  are used to identify one or more of the media content items  234 . In some embodiments, the playlists  239  identify a group of the media content items  234  in a particular order. In other embodiments, the playlists  239  merely identify a group of the media content items  234  without specifying a particular order. Some, but not necessarily all, of the media content items  234  included in a particular one of the playlists  239  are associated with a common characteristic such as a common genre, mood, or era. 
     In some embodiments, a user can listen to media content items in a playlist  239  by selecting the playlist  239  via a media playback device  104 , such as the PMSA system  110 . The media playback device  104  then operates to communicate with the media delivery system  112  so that the media delivery system  112  retrieves the media content items identified by the playlist  239  and transmits data for the media content items to the media playback device  104  for playback. 
     In some embodiments, the playlist  239  includes a playlist title and a list of content media item identifications. The playlist title is a title of the playlist, which can be provided by a user using the media playback device  104 . The list of content media item identifications includes one or more media content item identifications (IDs) that refer to respective media content items  234 . 
     Each media content item is identified by a media content item ID and includes various pieces of information, such as a media content item title, artist identification (e.g., individual artist name or group name, or multiple artist names or group names), and media content item data. In some embodiments, the media content item title and the artist ID are part of the media content metadata  236 , which can further include other attributes of the media content item, such as album name, length, genre, mood, era, etc. as described herein. 
     At least some of the playlists  239  may include user-created playlists. For example, a user of a media streaming service provided using the media delivery system  112  can create a playlist  239  and edit the playlist  239  by adding, removing, and rearranging media content items in the playlist  239 . A playlist  239  can be created and/or edited by a group of users together to make it a collaborative playlist. In some embodiments, user-created playlists can be available to a particular user only, a group of users, or to the public based on a user-definable privacy setting. 
     In some embodiments, when a playlist is created by a user or a group of users, the media delivery system  112  operates to generate a list of media content items recommended for the particular user or the particular group of users. In some embodiments, such recommended media content items can be selected based at least on the taste profiles  242  as described herein. Other information or factors can be used to determine the recommended media content items. Examples of determining recommended media content items are described in U.S. patent application Ser. No. 15/858,377, titled MEDIA CONTENT ITEM RECOMMENDATION SYSTEM, filed Dec. 29, 2017, the disclosure of which is hereby incorporated by reference in its entirety. 
     In addition or alternatively, at least some of the playlists  239  are created by a media streaming service provider. For example, such provider-created playlists can be automatically created by the media delivery system  112 . In some embodiments, a provider-created playlist can be customized to a particular user or a particular group of users. By way of example, a playlist for a particular user can be automatically created by the media delivery system  112  based on the user&#39;s listening history (e.g., the user&#39;s taste profile) and/or listening history of other users with similar tastes. In other embodiments, a provider-created playlist can be configured to be available for the public in general. Provider-created playlists can also be sharable with other users. 
     The user accounts  240  are used to identify users of a media streaming service provided by the media delivery system  112 . In some embodiments, a user account  240  allows a user to authenticate to the media delivery system  112  and enable the user to access resources (e.g., media content items, playlists, etc.) provided by the media delivery system  112 . In some embodiments, the user can use different devices (e.g., the PMSA system  110  and the mobile computing device  118 ) to log into the user account and access data associated with the user account in the media delivery system  112 . User authentication information, such as a username, an email account information, a password, and other credentials, can be used for the user to log into his or her user account. It is noted that, where user data is to be protected, the user data is handled according to robust privacy and data protection policies and technologies. For instance, whenever personally identifiable information and any other information associated with users is collected and stored, such information is managed and secured using security measures appropriate for the sensitivity of the data. Further, users can be provided with appropriate notice and control over how any such information is collected, shared, and used. 
     The taste profiles  242  contain records indicating media content tastes of users. A taste profile can be associated with a user and used to maintain an in-depth understanding of the music activity and preference of that user, enabling personalized recommendations, taste profiling and a wide range of social music applications. Libraries and wrappers can be accessed to create taste profiles from a media library of the user, social website activity and other specialized databases to obtain music preferences. 
     In some embodiments, each taste profile  242  is a representation of musical activities, such as user preferences and historical information about the users&#39; consumption of media content, and can include a wide range of information such as artist plays, song plays, skips, dates of listen by the user, songs per day, playlists, play counts, start/stop/skip data for portions of a song or album, contents of collections, user rankings, preferences, or other mentions received via a client device, or other media plays, such as websites visited, book titles, movies watched, playing activity during a movie or other presentations, ratings, or terms corresponding to the media, such as “comedy”, etc. 
     In addition, the taste profiles  242  can include other information. For example, the taste profiles  242  can include libraries and/or playlists of media content items associated with the user. The taste profiles  242  can also include information about the user&#39;s relationships with other users (e.g., associations between users that are stored by the media delivery system  112  or on a separate social media site). 
     The taste profiles  242  can be used for a number of purposes. One use of taste profiles is for creating personalized playlists (e.g., personal playlisting). An API call associated with personal playlisting can be used to return a playlist customized to a particular user. For example, the media content items listed in the created playlist are constrained to the media content items in a taste profile associated with the particular user. Another example use case is for event recommendation. A taste profile can be created, for example, for a festival that contains all the artists in the festival. Music recommendations can be constrained to artists in the taste profile. Yet another use case is for personalized recommendation, where the contents of a taste profile are used to represent an individual&#39;s taste. This API call uses a taste profile as a seed for obtaining recommendations or playlists of similar artists. Yet another example of taste profile use case is referred to as bulk resolution. A bulk resolution API call is used to resolve taste profile items to pre-stored identifiers associated with a service, such as a service that provides metadata about items associated with the taste profile (e.g., song tempo for a large catalog of items). Yet another example use case for taste profiles is referred to as user-to-user recommendation. This API call is used to discover users with similar tastes by comparing the similarity of taste profile item(s) associated with users. 
     A taste profile  242  can represent a single user or multiple users. Conversely, a single user or entity can have multiple taste profiles  242 . For example, one taste profile can be generated in connection with a user&#39;s media content play activity, whereas another separate taste profile can be generated for the same user based on the user&#39;s selection of media content items and/or artists for a playlist. 
     Referring still to  FIG. 3 , the PMSA server  202  operates to provide various functionalities to the PMSA system  110 . In some embodiments, the PMSA server  202  includes a personal media streaming appliance (PMSA) server application  250 , a processing device  252 , a memory device  254 , and a network access device  256 . The processing device  252 , the memory device  254 , and the network access device  256  may be similar to the processing device  214 , the memory device  216 , and the network access device  218 , respectively, which have each been previously described. 
     In some embodiments, the PMSA server application  250  operates to interact with the PMSA system  110  and enable the PMSA system  110  to perform various functions, such as receiving a user manual input, displaying information, providing notifications, performing power management, providing location-based services, and authenticating one or more users for the PMSA system  110 . The PMSA server application  250  can interact with other servers, such as the media content server  200  and the voice interaction server  204 , to execute such functions. 
     Referring still to  FIG. 3 , the voice interaction server  204  operates to provide various voice-related functionalities to the PMSA system  110 . In some embodiments, the voice interaction server  204  includes a voice interaction server application  270 , a processing device  272 , a memory device  274 , and a network access device  276 . The processing device  272 , the memory device  274 , and the network access device  276  may be similar to the processing device  214 , the memory device  216 , and the network access device  218 , respectively, which have each been previously described. 
     In some embodiments, the voice interaction server application  270  operates to interact with the PMSA system  110  and enable the PMSA system  110  to perform various voice-related functions, such as voice feedback and voice notifications. In some embodiments, the voice interaction server application  270  is configured to receive data (e.g., speech-to-text (STT) data) representative of a voice input received via the PMSA system  110  and process the data to determine a user command (e.g., a user request or instruction). In some embodiments, at least one of the media content server  200 , the PMSA server  202 , and the voice interaction server  204  may be used to perform one or more functions corresponding to the determined user command. 
       FIG. 4  is a block diagram of an example embodiment of the vehicle media playback system  114 . In this example, the vehicle media playback system  114  includes a vehicle head unit  302 , an amplifier  304 , and a speaker  306 . 
     The vehicle head unit  302  is configured to receive a user input and generate media content from various sources. In this example, the vehicle head unit  302  includes a receiver  310 , a wireless communication device  312 , a wired input device  314 , a processing device  316 , a memory device  318 , a user input assembly  320 , a display device  322 , and a stored media interface assembly  324 . 
     The receiver  310  operates to receive media content signals from various external sources. The received signals can then be used to generate media output by the vehicle media playback system  114 . Some embodiments of the receiver  310  include one or more tuners for receiving radio signals such as FM or AM radio signals. Other embodiments of the receiver  310  include a receiver for receiving satellite radio signals and/or a receiver for receiving internet radio signals. 
     The wireless communication device  312  operates to communicate with other devices using wireless data signals. The wireless communication device  312  can include one or more of a Bluetooth transceiver and a Wi-Fi transceiver. The wireless data signal may comprise a media content signal such as an audio or video signal. In some embodiments, the wireless communication device  312  is used to enable the vehicle media playback system  114  to wirelessly communicate with the PMSA system  110  and receive the media content signal  164  ( FIG. 2 ) from the PMSA system  110  via an in-vehicle wireless network. The in-vehicle wireless network between the PMSA system  110  and the vehicle media playback system  114  can be configured similarly to the in-vehicle wireless data communication  122  ( FIG. 2 ). 
     The wired input device  314  provides an interface configured to receive a cable for providing media content and/or commands. The wired input device  314  includes an input connector  340  configured to receive a plug extending from a media playback device for transmitting a signal for media content. In some embodiments, the wired input device  314  can include an auxiliary input jack (AUX) for receiving a plug from a media playback device that transmits analog audio signals. The wired input device  314  can also include different or multiple input jacks for receiving plugs from media playback devices that transmit other types of analog or digital signals (e.g., USB, HDMI, Composite Video, YPbPr, and DVI). In some embodiments, the wired input device  314  is also used to receive instructions from other devices. 
     In some embodiments, the wired input device  314  provides the input connector  340  (e.g., an AUX port) for receiving a connector  552  extending from the PMSA system  110 , as illustrated in  FIG. 6 . The media content signal  164  is then transmitted from the PMSA system  110  to the vehicle media playback system  114  via the cable  550 , the connector  552 , and the input connector  340 . 
     The processing device  316  operates to control various devices, components, and elements of the vehicle media playback system  114 . The processing device  316  can be configured similar to the processing device  148  ( FIG. 2 ) and, therefore, the description of the processing device  316  is omitted for brevity purposes. 
     In some embodiments, the processing device  316  operates to process the media content signal  164  received from the PMSA system  110  and convert the signal  164  to a format readable by the vehicle media playback system  114  for playback. 
     The memory device  318  is configured to store data and instructions that are usable to control various devices, components, and elements of the vehicle media playback system  114 . The memory device  318  can be configured similar to the memory device  150  ( FIG. 2 ) and, therefore, the description of the memory device  318  is omitted for brevity purposes. 
     The user input assembly  320  includes one or more input devices for receiving user input from users for controlling the vehicle media playback system  114 . In some embodiments, the user input assembly  320  includes multiple knobs, buttons, and other types of input controls for adjusting volume, selecting sources and content, and adjusting various output parameters. In some embodiments, the various input devices are disposed on or near a front surface of the vehicle head unit  302 . The various input devices can also be disposed on the steering wheel of the vehicle or elsewhere. Additionally or alternatively, the user input assembly  320  can include one or more touch sensitive surfaces, which can be incorporated in the display device  322 . 
     The display device  322  displays information. In some embodiments, the display device  322  includes a liquid crystal display (LCD) panel for displaying textual information about content and/or settings of the vehicle media playback system  114 . The display device  322  can also include other types of display panels such as a light emitting diode (LED) panel. In some embodiments, the display device  322  can also display image or video content. 
     The stored media interface assembly  324  reads media content stored on a physical medium. In some embodiments, the stored media interface assembly  324  comprises one or more devices for reading media content from a physical medium such as a compact disc or cassette tape. 
     The amplifier  304  operates to amplify a signal received from the vehicle head unit  302  and transmits the amplified signal to the speaker  306 . In this manner, the media output  124  can be played back at a greater volume. The amplifier  304  may include a power source to power the amplification. 
     The speaker  306  operates to produce an audio output (e.g., the media output  124 ) based on an electronic signal. The speaker  306  can include one or more vehicle embedded speakers  330  disposed at various locations within the vehicle  80 . In some embodiments, separate signals are received for at least some of the speakers (e.g., to provide stereo or surround sound). 
     In other embodiments, the speaker  306  can include one or more external speakers  332  which are arranged within the vehicle  80 . Users may bring one or more external speakers  332  into the vehicle  80  and connect the external speakers  332  to the vehicle head unit  302  using a wired interface or a wireless interface. In some embodiments, the external speakers  332  can be connected to the vehicle head unit  302  using Bluetooth. Other wireless protocols can be used to connect the external speakers  332  to the vehicle head unit  302 . In other embodiments, a wired connection (e.g., a cable) can be used to connect the external speakers  332  to the vehicle head unit  302 . Examples of the wired connection include an analog or digital audio cable connection and a universal serial bus (USB) cable connection. The external speaker  332  can also include a mechanical apparatus for attachment to a structure of the vehicle. 
       FIG. 5  is a block diagram of an example embodiment of the mobile computing device  118  of  FIG. 1 . 
     Similar to the PMSA system  110 , the mobile computing device  118  can also be used to play media content. For example, the mobile computing device  118  is configured to play media content that is provided (e.g., streamed or transmitted) by a system external to the mobile computing device  118 , such as the media delivery system  112 , another system, or a peer device. In other examples, the mobile computing device  118  operates to play media content stored locally on the mobile computing device  118 . In yet other examples, the mobile computing device  118  operates to play media content that is stored locally as well as media content provided by other systems. 
     In some embodiments, the mobile computing device  118  is a handheld or portable entertainment device, smartphone, tablet, watch, wearable device, or any other type of computing device capable of playing media content. In other embodiments, the mobile computing device  118  is a laptop computer, desktop computer, television, gaming console, set-top box, network appliance, blue-ray or DVD player, media player, stereo, or radio. 
     As described herein, the mobile computing device  118  is distinguished from the PMSA system  110  in various aspects. For example, unlike the PMSA system  110 , the mobile computing device  118  is not limited to playing media content, but configured for a wide range of functionalities in various situations and places. The mobile computing device  118  is capable of running a plurality of different software applications for different purposes. The mobile computing device  118  enables the user to freely start or stop activation of such individual software applications. 
     In at least some embodiments, the mobile computing device  118  includes a location-determining device  402 , a display screen  404 , a processing device  406 , a memory device  408 , a media content output device  410 , and a network access device  412 . Other embodiments may include additional, different, or fewer components. For example, some embodiments may include a recording device such as a microphone or camera that operates to record audio or video content. 
     The location-determining device  402  is a device that determines the location of the mobile computing device  118 . In some embodiments, the location-determining device  402  uses one or more of Global Positioning System (GPS) technology (which may receive GPS signals), Global Navigation Satellite System (GLONASS), cellular triangulation technology, network-based location identification technology, Wi-Fi positioning systems technology, and combinations thereof. 
     The display screen  404  is configured to display information. In addition, the display screen  404  is configured as a touch sensitive display and includes a user interface  420  for receiving a user input from a selector (e.g., a finger, stylus etc.) controlled by the user U. In some embodiments, therefore, the display screen  404  operates as both a display device and a user input device. The touch sensitive display screen  404  operates to detect inputs based on one or both of touches and near-touches. In some embodiments, the display screen  404  displays a graphical user interface for interacting with the mobile computing device  118 . Other embodiments of the display screen  404  do not include a touch sensitive display screen. Some embodiments include a display device and one or more separate user interface devices. Further, some embodiments do not include a display device. 
     In some embodiments, the processing device  406  comprises one or more central processing units (CPU). In other embodiments, the processing device  406  additionally or alternatively includes one or more digital signal processors, field-programmable gate arrays, or other electronic circuits. 
     The memory device  408  operates to store data and instructions. In some embodiments, the memory device  408  stores instructions for a media playback engine  430 . The memory device  408  may be configured similarly to the memory device  150  ( FIG. 2 ) and, therefore, the description of the memory device  408  is omitted for brevity purposes. 
     The media playback engine  430  operates to play media content to the user U. As described herein, the media playback engine  430  is configured to communicate with the media delivery system  112  to receive one or more media content items (e.g., through the stream media  232 ). In other embodiments, the media playback engine  430  is configured to play media content that is locally stored in the mobile computing device  118 . 
     In some embodiments, the media playback engine  430  operates to retrieve one or more media content items that are either locally stored in the mobile computing device  118  or remotely stored in the media delivery system  112 . In some embodiments, the media playback engine  430  is configured to send a request to the media delivery system  112  for media content items and receive information about such media content items for playback. 
     Referring still to  FIG. 5 , the media content output device  410  operates to output media content. In some embodiments, the media content output device  410  generates media output  450  for the user U. In some embodiments, the media content output device  410  includes one or more embedded speakers  452  which are incorporated in the mobile computing device  118 . Therefore, the mobile computing device  118  can be used as a standalone device that generates the media output  450 . 
     In addition, some embodiments of the mobile computing device  118  include an external speaker interface  454  as an alternative output of media content. The external speaker interface  454  is configured to connect the mobile computing device  118  to another system having one or more speakers, such as headphones, portal speaker assemblies, and the vehicle media playback system  114 , so that the media output  450  is generated via the speakers of the other system external to the mobile computing device  118 . Examples of the external speaker interface  454  include an audio output jack, a Bluetooth transmitter, a display panel, and a video output jack. Other embodiments are possible as well. For example, the external speaker interface  454  is configured to transmit a signal through the audio output jack or Bluetooth transmitter that can be used to reproduce an audio signal by a connected or paired device such as headphones or a speaker. 
     The network access device  412  operates to communicate with other computing devices over one or more networks, such as the network  116  and the in-vehicle wireless data communication  122 . Examples of the network access device  412  include wired network interfaces and wireless network interfaces. Wireless network interfaces includes infrared, BLUETOOTH® wireless technology, 802.11a/b/g/n/ac, and cellular or other radio frequency interfaces in at least some possible embodiments. 
       FIG. 6  schematically illustrates an example embodiment of the PMSA system  110  of  FIG. 1 . In this example, the PMSA system  110  includes a personal media streaming appliance (PMSA)  500  and a docking device  502 . 
     As described herein, the PMSA system  110  is sized to be relatively small so that the PMSA system  110  can be easily mounted to a structure (e.g., a dashboard or head unit) of the vehicle  80  where the user can conveniently manipulate the PMSA system  110 . By way of example, the PMSA system  110  is configured to be smaller than a typical mobile computing device, such as a smartphone. Further, the PMSA  500  provides a simplified user interface for controlling playback of media content. For example, the PMSA  500  has a limited set of physical control elements, such as a single rotary knob and one or more physical buttons as described below, so that the user can easily control the PMSA system  110  in the vehicle  80  ( FIG. 1 ). 
     The PMSA  500  is configured to include at least some of the devices of the PMSA system  110  as illustrated with reference to  FIG. 2 . In some embodiments, the PMSA  500  includes all of the devices of the PMSA system  110  as illustrated in  FIG. 2 . 
     As illustrated also in  FIG. 2 , some embodiments of the PMSA  500  include the user input device  130  that includes the manual input device  160  and the sound detection device  162 . Some embodiments of the manual input device  160  include a control knob assembly  510  and one or more physical button assemblies  512 . 
     In some embodiments, the control knob assembly  510  is configured to be maneuverable in multiple ways. For example, the control knob assembly  510  provides a plurality of regions on a knob face  514  that are independently depressible upon receiving a user&#39;s pressing action against the knob face  514 . In the illustrated example, the control knob assembly  510  has five regions  516 A-E (collectively  516 ) (e.g., up, down, left, right, and middle) that are separately depressible. At least some of the regions  516  are configured to receive inputs of different user commands (e.g., requests or instructions). 
     In other embodiments, the control knob assembly  510  is configured to be manipulated in different ways, such as tilting in multiple directions or sliding in multiple directions. 
     In addition, the control knob assembly  510  is configured to be rotatable. For example, the user can hold the control knob assembly  510  and rotate with respect to a body  520  of the PMSA  500 . The control knob assembly  510  can be rotatable in both directions  522  (e.g., clockwise and counterclockwise). In other embodiments, the control knob assembly  510  is configured to rotate in only one direction. 
     The control knob assembly  510  is used to receive user inputs for controlling playback of media content. In addition or alternatively, the control knob assembly  510  can be used to receive user inputs for other purposes or functions. 
     The physical button assemblies  512  are configured to be depressed upon receiving a user&#39;s pressing action against the physical button assemblies  512 . In the illustrated example, the PMSA  500  has four physical button assemblies  512 A- 512 D (collectively  512 ). In some embodiments, each of the physical button assemblies  512  is configured to receive a single user command. In other embodiments, at least one of the physical button assemblies  512  is configured to receive multiple user commands. 
     In some embodiments, the physical button assemblies  512  are used as button assemblies that are preset to be associated with particular media content, thereby facilitating playback of such media content. In these embodiments, the physical button assemblies  512  are also referred to as preset button assemblies  512 . 
     In some embodiments, the preset buttons  512  are configured to receive the manual input  154  to play media content that are preset to the respective preset buttons  512 . In some embodiments, the preset button assemblies  512  are arranged at the front side of the body  520 . In the illustrated example, four preset buttons  512 A,  512 B,  512 C, and  512 D (collectively  512 ) are provided at the front side of the body  520 . 
     The preset buttons  512  can be distinguished from each other in various methods. In the illustrated example, different numbers of dots are used to indicate different preset buttons  512 . For example, the preset buttons  512 A,  512 B,  512 C, and  512 D are provided with one dots, two dots, three dots, and four dots, respectively. The dots can be configured with at least partially tubes that can protrude above the surface of the front side to provide tactile sensation when touched or pressed by a user. The dots can be made of at least transparent material and lit by one or more light sources from the inside of the body  520 . In other embodiments, different elements, such as symbols, characters, signs, printed elements or structures, or indicia can be used to differentiate the preset buttons  512 . In some embodiments, such elements can be configured to emit light. By way of example, such elements can be at least partially made of self-luminous material. Such illumination of light can be configured to occur when the environment becomes dark. 
     In some embodiments, the preset buttons  512  can be actuated by a pressing action against the preset buttons  512 . For example, the preset buttons  512  are configured to be depressed when a user presses the preset buttons  512  against the surface of the front side of the body  520 , and the preset buttons  512  operate to detect the depression thereof. 
     In some embodiments, each of the preset buttons  512  is configured to receive a single user command. For example, the preset button assemblies  512  are configured such that a single pressing action against each of them corresponds to a single input. In other embodiments, at least one of the preset buttons  512  is configured to receive multiple user commands. For example, different pressing actions (e.g., a set of pressing and releasing, a set of pressing and holding for a predetermined period of time, a set of multiple pressings for a predetermined of time, etc.) can correspond to different user inputs. 
     In other embodiments, the physical buttons  512  can be used for non-content related actions. By way of example, the physical buttons  512  can be used for playback control actions, such as playback mode (e.g., shuffle, repeat, normal, etc.), playback speed (e.g., normal, slower, faster, etc.), crossfade (e.g., crossfade length), equalizer settings, audio normalization, and other possible settings relating to media content playback. Further, the physical buttons  512  can be used to connect the PMSA system  110  with other devices, such as the computing device  118 . 
     It should be understood that physical buttons  512  can be any known or future developed component that is used to provide an activation signal to a processing device. For example physical buttons  512  can be mechanical button switches, conductive button switches, or capacitive button switches. 
     Although the present disclosure is primarily described herein with reference to physical preset buttons of the media playback device  104 , such as the PMSA system  110 , it is understood that the present disclosure is similarly applicable for other types of presets in the media playback device  104 , such as presets that are voice-controlled without physical buttons. For example, the presets associated with the physical preset buttons  512  can be also activated by a voice command. By way of example, the PMSA system  110  receives a voice command from a user that requests for media content associated with a preset button  512 , and the voice command (e.g., an utterance) is analyzed to identify the user request. Such analysis can be performed either locally in the PMSA system  110  or in the backend server (e.g., the media delivery system  112 ), or both. Then, the media delivery system  112  can determine media content associated with the preset button  512  and transmit a signal representative of the media content to the PMSA system  110  for playback. 
     In other embodiments, in addition to, or alternative to, the physical preset buttons  512 , voice-only presets can be provided for the PMSA system  110 . Such voice-only presets can be created and stored in the PMSA system  110  locally and/or in the backend server, and be operated only by a voice command. In some embodiments, the voice-only presets can be shared among different media playback devices associated with the same user account. 
     In addition, the PMSA  500  also includes the display screen  132 . In some embodiments, the display screen  132  is arranged at the knob face  514  of the control knob assembly  510 . As described herein, in some embodiments, the display screen  132  does not include a touch sensitive display screen, and is configured as a display device only. In other embodiments, however, the display screen  132  can be configured to be touch sensitive and receive a user input through the display screen  132  as well. 
     Referring still to  FIG. 6 , the docking device  502  is configured to mount the PMSA  500  to a structure of the vehicle  80 . The docking device  502  is configured to removably mount the PMSA  500  thereto. The docking device  502  is further configured to attach to a structure of the vehicle  80  ( FIG. 1 ) so that the PMSA  500  is positioned at the structure of the vehicle  80 . 
     In some embodiments, an interface between the PMSA  500  and the docking device  502  is configured to prevent the PMSA  500  from rotating relative to the docking device  502  when the control knob assembly  510  is manipulated by a user. For example, the docking device  502  has a portion (e.g., a front portion of the docking device  502 ) configured to interlock a corresponding portion of the PMSA  500  (e.g., a rear portion of the PMSA  500 ) when the PMSA  500  is mounted to the docking device  502  such that the portion of the docking device  502  and the corresponding portion of the PMSA  500  form the interface therebetween. 
     In addition or alternatively, the PMSA  500  and the docking device  502  include magnetic materials at the interface therebetween so that the PMSA  500  and the docking device  502  are magnetically coupled to each other. 
     In some embodiments, the docking device  502  includes one or more electrical contacts  530  that are electrically connected to corresponding electrical contacts (not shown in  FIG. 6 ) of the PMSA  500  when the PMSA  500  is mounted to the docking device  502 . Such electrical connection between the PMSA  500  and the docking device  502  is provided for various functions. 
     In some embodiments, as described herein, the PMSA  500  does not include a battery sufficient for a prolonged use without an external power supply. In some embodiments, the PMSA  500  is primarily powered by a vehicle power supply  540 . In some embodiments, the docking device  502  has a power receiving line  544  for connection to the vehicle power supply  540 . For example, the power receiving line  544  extends from the docking device  502  and has a power connector  546  at a free end that is configured to mate with a vehicle power outlet  542  (e.g., a 12V auxiliary power outlet) of the vehicle power supply  540 . As such, the docking device  502  receives electric power from the vehicle power supply  540  via the power receiving line  544 , and the electrical connection between the PMSA  500  and the docking device  502  is configured to deliver electric power from the docking device  502  to the PMSA  500 . 
     In some embodiments, as described herein, the PMSA  500  does not have a speaker and is designed to transmit media content signals to the vehicle media playback system  114  so that the media content is played through the vehicle media playback system  114 . In some embodiments, the docking device  502  includes a media content output line  550  (also referred to herein as a media content output cable) (e.g., an auxiliary (AUX) output) configured to connect with the vehicle media playback input connector  340  (e.g., an auxiliary (AUX) port) of the vehicle media playback system  114 . The docking device  502  is configured to receive media content signals from the PMSA  500  via the electrical connection between the PMSA  500  and the docking device  502 , and transmit the signals to the vehicle media playback system  114  via the media content output line  550 . In the illustrated embodiment, the power receiving line  544  and the media content output line  550  are combined to be a single line extending from the docking device  502  until the power connector  546 , and the media content output line  550  further extends (or branches out) from the power connector  546  and terminates at a media output connector  552 . The media output connector  552  is configured to connect to the vehicle media playback input connector  340  of the vehicle media playback system  114 . In other embodiments, the media content output line  550  and the power receiving line  544  extend separately from the docking device  502 . 
     In other embodiments, one or more of the power receiving line  544  and the media content output line  550  are directly connected to, and extend from, the PMSA  500  so that electric power is directly supplied to the PMSA  500  without the docking device  502  involved, and that the media content is directly transmitted to the vehicle media playback system  114  without passing through the docking device  502 . 
     In some embodiments, the electrical connection between the PMSA  500  and the docking device  502  can be used to detect connection between the PMSA  500  and the docking device  502 . 
       FIG. 7  is a block diagram of an example embodiment of the PMSA  500  of the PMSA system  110 . In some embodiments, the PMSA  500  can include at least some of the devices of the PMSA system  110 . Where same or similar devices are shown in this example, the same reference numbers will be used and the description of such same or similar devices is omitted or briefly provided for brevity purposes. 
     In some embodiments, the PMSA  500  can include the processing device  148  and the memory device  150  as described herein. In addition, the PMSA  500  can include a manual user interface system  602 , a cellular-based media streaming system  604 , a noise-cancelling voice interaction system  606 , and an appliance operation system  608 . In some embodiments, the PMSA  500  can include local data  610 . In other embodiments, the PMSA  500  can include other devices or systems, such as at least one of the devices and the engines as illustrated and described with reference to  FIG. 2 . 
     The manual user interface system  602  is configured to receive manual user input for controlling playback of media content. In some embodiments, the manual user interface system  602  includes the rotatable manual control knob assembly  510  and a plurality of depressible preset button assemblies  512 . The control knob assembly  510  and the preset button assemblies  512  are illustrated and described herein in more detail, such as with reference to  FIG. 10 . 
     In some embodiments, the manual user interface system  602  includes the manual input processing engine  178 . As described herein, in some embodiments, the manual input processing engine  178  is included in the memory device  150  and configured to detect the manual user input and control playback of the media content based on the manual user input. In some embodiments, the manual input processing engine  178  includes a control knob input processing engine  620  and a preset button input processing engine  622 . 
     The control knob input processing engine  620  operates to receive the manual input via the control knob assembly  510 . In some embodiments, the control knob assembly  510  includes one or more sensors that detect manual inputs (e.g., press and rotation) and generate electric signals representative of the manual inputs when actuated. The control knob input processing engine  620  operates to process the electric signals and determine the user request (e.g., instruction or command) corresponding to the manual input. 
     The preset button input processing engine  622  operates to receive the manual input via at least one of the preset button assemblies  512 . In some embodiments, the preset button assemblies  512  include one or more sensors that detect manual inputs (e.g., press) and generate electric signals representative of the manual inputs when actuated. The preset button input processing engine  622  operates to process the electric signals and determine the user request (e.g., instruction or command) corresponding to the manual input. 
     The cellular-based media streaming system  604  is configured to communicate with a media content provider (also referred to herein as a media streaming service provider or the like), such as the media delivery system  112 , and receive media content from the media content provider via a cellular network. In some embodiments, the cellular-based media streaming system  604  includes the wireless data communication device  134 . As described herein, the wireless data communication device  134  can be configured to communicate with the media content provider via a cellular network. 
     In some embodiments, the media content provider includes a media content source as shown in the media delivery system  112 . In other embodiments, the media content provider can include other content service providers with other computing devices (e.g., servers), such as a news service provider, a weather service provider, or any other content sources. 
     In some embodiments, the cellular-based media streaming system  604  includes the wireless data communication engine  184 . As described herein, in some embodiments, the wireless data communication engine  184  is included in the memory device  150  and configured to interact with the wireless data communication device  134  and enable the PMSA system  110  to communicate with the media content provider. In some embodiments, the wireless data communication engine  184  can transmit at least one of a device identifier and a user account identifier to the media content provider and receive media content associated with the at least one of the device identifier and the user account identifier from the media content provider at least partially via the cellular network. As described herein, the device identifier identifies the PMSA  500 , and the user account identifier identifies the user account associated with the PMSA  500 . The media content provider can operate to determine media content based on the device identifier and/or the user account identifier and transmit the media content to the PMSA  500  at least partially via the cellular network. 
     The noise-cancelling voice interaction system  606  is configured to provide voice assistant functions with noise-cancellation technology. In some embodiments, the noise-cancelling voice interaction system  606  includes the sound detection device  162  as described herein. For example, the noise-cancelling voice interaction system  606  includes at least one microphone configured to detect sounds in the vehicle. 
     In some embodiments, the noise-cancelling voice interaction system  606  includes the sound processing engine  180  and the voice interaction engine  182 . As described herein, the sound processing engine  180  can operate to identify a voice input from the detected sounds in the vehicle. The voice interaction engine  182  can operate to cooperate with the media content provider to determine a command intended by the voice input. 
     The appliance operation system  608  is configured to manage operation of the PMSA  500 . In some embodiments, the appliance operation system  608  includes at least one of the media content output device  140 , the power supply device  144 , and the power input device  146 . 
     As described herein, the media content output device  140  (also referred to herein the media content output interface) is configured to enable the PMSA  500  to transmit media content to the vehicle media playback device  114 . The media content output device  140  can be of various types, such as an auxiliary (AUX) output interface, a USB output interface, or a wireless output interface (e.g., Bluetooth, NFC, or Wi-Fi). As described herein, the power supply device  144  operates to store electric power to be used in the PMSA  500 . The power input device  146  can be configured to be electrically connected to a power source of the vehicle and receive electric power from the vehicle. 
     In some embodiments, the appliance operation system  608  can include at least one of the media content processing engine  176 , the power management engine  186 , and an appliance activation engine  630 . As described herein, the media content processing engine  176  can operate to process media content and generate a media content signal based on the media content. The media content processing engine  176  can transmit the media content signal to the vehicle media playback system  114  through the media content output device  140  so that the vehicle media playback system can use the media content signal to play the media content. 
     As described herein, the power management engine  186  is configured to charge the power supply device  144  (e.g., the battery with the electric power received from the power source of the vehicle through the power input device  146 . 
     In some embodiments, the appliance activation engine  630  is configured to at least partially manage and operate at least one of the other engines of the PMSA  500 . In some embodiments, the appliance activation engine  630  can be automatically activated by the processing device  148  upon powering up the PMSA  500 , and the appliance activation engine  630  at least partially operates at least one of the other engines of the PMSA  500  upon activation. 
     In some embodiments, the appliance activation engine  630  can continue running until the PMSA  500  is powered off or down below a predetermined power level. 
     In some embodiments, the appliance activation engine  630  is provided by the media content provider (e.g., the media delivery system  114 . In some embodiments, the PMSA  500  is free of user interface controls that would allow a user to disable operation of the appliance activation engine  630  on the PMSA  500 . As such, the operation of the appliance activation engine  630  is not configurable or programmable by a user so that the PMSA  500  automatically starts and continues running until the PMSA  500  is powered off or down to a predetermined power level (e.g., sleep mode). 
     Referring still to  FIG. 7 , the PMSA  500  can include the local data  610 . The local data  610  is stored locally in the PMSA  500 . The local data  610  include data associated with the PMSA  500 . An example of the local data  610  is illustrated and described in further detail herein, such as with reference to  FIG. 8 . 
     As described herein, the PMSA  500  can operate to receive the user input  152  from a user U for controlling the PMSA  500 , such as the manual input  154  or the voice input  156 . The PMSA  500  can operate to process the user input  152  and generate a request signal  640  based on the user input  152 . The request signal  640  represents a user request intended by the user input  152 . The PMSA  500  can transmit the request signal  640  to the media content provider, such as the media delivery system  112 , so that the media content provider can perform a function intended by the user request based on the request signal  640 . For example, the media content provider can determine media content  642  associated with the request signal  640  and transmit the media content  642  to the PMSA  500  for playback. An example of the request signal  640  is illustrated and described in further detail herein, such as with reference to  FIG. 9 . 
     In some embodiments, where the user input  152  is the manual input  154 , the manual user interface system  602  can at least partially operate to generate the request signal  640 . Where the user input  152  is the voice input  156 , the noise-cancelling voice interaction system  606  can at least partially operate to generate the request signal  640 . In some embodiments, the cellular-based media streaming system  604  can at least partially operate to transmit the request signal  640  to the media content provider. 
       FIG. 8  illustrates an example data structure  650  of the local data  610 . As described above, the local data  610  can be stored in the PMSA system  110 . In some embodiments, the local data  610  include a user account identifier  652 , a device identifier  654 , and preset button information  656 . In other embodiments, the local data  610  can include other information, such as playback setting information (e.g., playback mode (shuffle, repeat, normal, etc.), playback speed, sound quality, etc.). 
     The user account identifier  652  is information that identifies a user account associated with the PMSA system  110 . The device identifier  654  is information that identifies the PMSA system  110 . 
     The preset button information  656  includes information about one or more preset buttons  512  of the PMSA system  110 . In some embodiments, the preset button information  656  includes a preset name  660 , a preset button identifier (ID)  662 , and a media context identifier (ID)  664 . The preset name  660  is a name of a preset button  512 . The preset name  660  can be predetermined with a word or phrase (e.g., “Preset  1 ,” “Preset  2 ,” “Preset  3 ,” and “Preset  4 ”). In other embodiments, the preset name  660  can be reset or renamed as desired by a user. The preset button identifier  662  is configured to identify an associated preset button  512 . The media context identifier  664  is configured to identify a media context that is associated with a corresponding preset button  512 . In some embodiments, the preset button identifier  662  and/or the media context identifier  664  are configured as Uniform Resource Identifiers (URIs). 
       FIG. 9  illustrates an example of the request signal  640  of  FIG. 7 . In some embodiments, the request signal  640  conveys a media playback control request  670 , a user account identifier  672 , and a device identifier  674 . 
     As described herein, the request signal  640  is transmitted from the PMSA  500  to the media content provider, such as the media delivery system  112 . The request signal  640  includes information that is usable by the media delivery system  112  to perform functions requested by the user input  152  via the PMSA  500 . In some embodiments, the request signal  640  is generated based at least in part on the local data  610 . 
     In some embodiment, the media playback control request  670  can include a request for controlling playback of media content (e.g., a media context  238 ), such as playing, stopping playback, changing playback settings, and other controlling associated with media content playback. In some embodiments, the media playback control request  670  can be at least one of a control knob based request  680 , a preset based request  682 , and a voice request  684 . 
     The control knob based request  680  includes a request that is received via the control knob  514 . As described herein, the PMSA  500  operates to receive the user manual input  154  (e.g., a pressing action or a rotating action) via the control knob  514  and process the user manual input  154  to determine the request intended by the user input. 
     The preset based request  682  includes a request that is received via a preset button  512  of the PMSA  500 . As described herein, the PMSA  500  operates to receive the user manual input  154  (e.g., a pressing action) via the preset button  512  and process the user manual input  154  to determine the request intended by the user input. 
     The voice request  684  includes a request that is received via the sound detection device  162  (e.g., one or more microphone) of the PMSA  500 . As described herein, the PMSA  500  operates to the receive the voice input  156  via the sound detection device  162  and process the voice input  156  to determine the request intended by the user input. 
     The user account identifier (ID)  672  is information that identifies a user account associated with the PMSA  500  at which the media playback control request  670  is received. In some embodiments, the user account identifier  672  is retrieved from the local data  610  (e.g., the user account identifier  652 ). 
     The device identifier (ID)  674  is information that identifies the PMSA  500  at which the media playback control request  670  is received. In some embodiments, the device identifier  674  is retrieved from the local data  610  (e.g., the device identifier  654 ). 
     Where the preset based request  682  is involved, the request signal  640  can include a preset button identifier (ID)  686 . The preset button identifier  686  is information that identifies the preset button  512  of the PMSA  500  via which the media playback control request  670  is received. In some embodiments, the preset button identifier  676  is retrieved from the local data  610  (e.g., the preset button identifier  662 ). 
     In alternative embodiments, the request signal  640  can further include other information usable by the media content provider. Examples of such other information include a preset name of the selected preset button, a media context identifier associated with the selected preset button, playback setting information, and any other suitable information associated with or stored in the PMSA  500 . 
     Referring to  FIGS. 10-16 , an example hardware structure of the PMSA system  110  is described. For example,  FIGS. 10-13  illustrate an example of the PMSA  500 , and  FIGS. 14-16  illustrate an example of the docking device  502 . At least some hardware features of the PMSA system  110  have been illustrated and described herein, such as with reference to  FIGS. 2, 6, and 7 . To the extent appropriate, the same reference numbers can be used and the description of such same or similar devices is omitted or briefly provided for brevity purposes. 
       FIG. 10  is a front perspective view of an example of the PMSA  500 . In some embodiments, the PMSA  500  includes a body  702  having a front side  704  and a rear side  706  opposite to the front side  704 . The body  702  has opposite lateral sides, such as a first lateral side  708  and an opposite second lateral side  710 . The body  702  defines an interior space  712  ( FIG. 13 ). 
     As described herein, the PMSA  500  includes the user input device  130 , such as the manual input device  160  and the sound detection device  162 . In some embodiments, the manual input device  160  includes a playback control assembly configured to control playback of media content. The manual input device  160  includes a control knob assembly  510  and one or more preset button assemblies  512 . 
     The control knob assembly  510  is manually operable in a plurality of movements relative to the body  702 . The plurality of movements correspond to a plurality of manual inputs. In some embodiments, the plurality of movements includes a rotational movement of at least a portion of the control knob assembly  510  relative to the body  702 . 
     The control knob assembly  510  is arranged at the front side  704  of the body  702 . In some embodiments, the control knob assembly  510  is disposed off the center of the front side  704  of the body  702  so that it is located to be biased toward either of the lateral sides  708  and  710 . In this example, the control knob assembly  510  is arranged closer to the first lateral side  708  than to the second later side  710 . Therefore, the center of the rotation of the control knob assembly  510  is spaced apart from the center of the body  702 . The off-centered position of the control knob assembly  510  can prevent the body  702  of the PMSA  500  from rotating together with the control knob assembly  510  when the user operates the control knob assembly  510  to rotate relative to the body  702 . Further, the off-centered position of the control knob assembly  510  can allow the body  702  to be securely mounted to the docking device  502  while the user rotates the control knob assembly  510 , at least partially because the rotation of the control knob assembly  510  does not cause a rotation of the body  702  around its own center. 
     In some embodiments, the control knob assembly  510  has the front face  514  and a rotary knob  720 . The front face  514  and the rotary knob  720  can be used to receive the manual input  154  in various ways. 
     As described herein, the front face  514  is configured to be depressible in multiple ways upon receiving a pressing action against different regions of the front face  514 . In some embodiments, the front face  514  has five input regions  516 A,  516 B,  516 C,  516 D, and  516 E (collectively  516 ) that are separately depressible. Actuation of different input regions  516  can be associated with different functions so that, when different input regions  516  are depressed by the manual input  154 , different functions are performed. Such different functions can be associated with controlling of media content playback, such as play, stop (including pause), fast forward, fast reverse, skip, change playback mode (e.g., shuffle, repeat, normal, etc.), and other playback controls. Other functions or commands can be associated with, and triggered by, at least one of the input regions  516 . 
     The rotary knob  720  is configured to rotate by the manual input  154 . In some embodiments, the rotary knob  720  provides a peripheral grip surface  722  that can be gripped by one or more fingers of the user. By way of example, the user can hold the rotary knob  720  by gripping the peripheral grip surface  722  with fingers, and rotate the rotary knob  720  relative to the body  702 . 
     In some embodiments, the rotary knob  720  can rotate in a plurality of directions, such as a first rotational direction  724  and an opposite second rotational direction  726 . In other embodiments, the rotary knob  720  is configured to rotate in only on direction. In some embodiments, the rotary knob  720  is configured to continue to rotate in at least one of the possible rotational directions, without returning to a predetermined position. In other embodiments, the rotary knob  720  is configured to return to a predetermined default (or original) position when the rotary knob  720  is released after being rotated by a rotating action of the user. 
     In some embodiments, the rotary knob  720  is rotatable in various ways for receiving various inputs. For example, different functions or commands can be associated with different manipulations of the rotary knob  720 , such as different magnitudes of rotation of the rotary knob  720 , different speeds of rotation of the rotary knob  720 , different directions of rotation of the rotary knob  720 , and/or any other rotational control skims. 
     In some embodiments, the front face  514  is independently operable from the rotary knob  720 . For example, the front face  514  can be depressed while the rotary knob  720  remains stationary upon the pressing action against the front face  514 . Similarly, the rotary knob  720  can rotate around the front face  514  while the front face  514  remains stationary. In other embodiments, the control knob assembly  510  can be configured such that the front face  514  and the rotary knob  720  can be depressed together upon receiving the pressing action against the front face  514 . In yet other embodiments, the control knob assembly  510  can be configured to be depressed as a whole when the front face  514  is depressed. 
     In some embodiments, the control knob assembly  510  is configured to be controlled in different ways. For example, the control knob assembly  510  is configured to be tilted multiple sideways (e.g., up, down, left, and right). In other examples, the control knob assembly  510  is configured to slide multiple sideways (e.g., up, down, left, and right). In addition, the control knob assembly  510  can be depressed upon pressing at the center as described herein. 
     As described herein, in some embodiments, the PMSA  500  includes the display screen  132  that is arranged at the knob face  514  of the control knob assembly  510 . In some embodiments, the display screen  132  can display information relating to media content playback. 
     In other embodiments, the display screen  132  can display other pieces of information. In some embodiments, the display screen  132  is configured as a display device only and is not touch sensitive. In other embodiments, the display screen  132  can be configured to be touch sensitive and receive a user input through the display screen  132  as well. 
     Referring still to  FIG. 10 , as described herein, the preset button assemblies  512  are configured to receive the manual input  154  to play media content that are preset to the respective preset button assemblies  512 . 
     In some embodiments, the preset button assemblies  512  are arranged at the front side  704  of the body  702 . In the illustrated example, four preset button assemblies  512 A,  512 B,  512 C, and  512 D (collectively  512 ) are provided at the front side  704  of the body  702 . 
     The preset button assemblies  512  can be distinguished from each other in various methods. In the illustrated example, different numbers of dots are used to indicate different preset button assemblies  512 . For example, the preset button assemblies  512 A,  512 B,  512 C, and  512 D are provided with one dot  730 A, two dots  730 B, three dots  730 C, and four dots  730 D, respectively. The dots  730  (including  730 A,  730 B,  730 C, and  730 D) can be configured with at least partially tubes that can protrude above the surface of the front side  704  to provide tactile sensation when touched or pressed by a user. The dots can be made of at least transparent material and lit by one or more light sources from the inside of the body  702 . In other embodiments, different symbols, signs, or indicia can be used to differentiate the preset button assemblies  512 . 
     In some embodiments, the preset button assemblies  512  can be actuated by a pressing action against the physical button assemblies  512 . For example, the preset button assemblies  512  are configured to be depressed when a user presses the preset button assemblies  512  against the surface of the front side  704 , and the preset button assemblies  512  operate to detect the depression thereof. 
     In some embodiments, each of the physical button assemblies  512  is configured to receive a single user command. For example, the preset button assemblies  512  are configured such that a single pressing action against each of them corresponds to a single input. In other embodiments, at least one of the physical button assemblies  512  is configured to receive multiple user commands. For example, different pressing actions (e.g., a set of pressing and releasing, a set of pressing and holding for a predetermined period of time, a set of multiple pressings for a predetermined of time, etc.) can correspond to different user inputs. 
     Referring still to  FIG. 10 , as described herein, the sound detection device  162  operates to detect sounds in or adjacent the PMSA  500 . The sound detection device  162  can detect the voice input  156 . In some embodiments, the sound detection device  162  includes one or more acoustic sensors, such as microphones. In the illustrated example, two microphones  740 A and  740 B (collectively  740 ) are used for the sound detection device  162 . In other embodiments, more than two microphones  740  can be used. In some embodiments, the microphones  740 A and  740 B are arranged at the front side  704  of the body  702 . For example, the microphones  740  are disposed in the interior  712  of the body  702  adjacent (e.g., underneath) the front side  704  of the body  702 . The body  702  can have two microphone holes  742  that are aligned with the microphones  740  within the body  702  so that the microphones  740  are at least partially exposed at the front side  704  of the body  702 . In other embodiments, one or more microphones  740  can be arranged in other locations in the front side  704  and/or in other sides of the body  702 . 
     Such multiple microphones  740  can be used to cancel noises from the received sounds so that a desired sound (e.g., the voice input  156 ) is clearly identified. In this example, two microphones  740  of the sound detection device  162  are arranged apart from each other in the body  702  such that ambient noise is effectively canceled from the voice input  156  when the sounds are detected by the microphones  740 . 
       FIG. 11  is a rear perspective view of the PMSA  500  of  FIG. 10 . In some embodiments, the PMSA  500  includes a dock mounting structure  750 , one or more appliance connectors  760 , and one or more appliance control interfaces  762 . 
     The dock mounting structure  750  can be arranged at the rear side  706  of the body  702 . The dock mounting structure  750  is configured to engage the docking device  502  (e.g., an appliance coupling structure  840  of the docking device  502  in  FIG. 14 ). An example engagement between the PMSA  500  and the docking device  502  is described in more detail herein, such as with reference to  FIG. 14 . 
     In some embodiments, the dock mounting structure  750  is configured to provide anti-rotation structure that prevents the PMSA  500  from disengaging from the docking device  502  or rotating relative to the docking device  502  when the control knob assembly  510  (e.g., the rotary knob  720  thereof) is rotated by the user&#39;s rotating manual input. In some embodiments, the dock mounting structure  750  is constructed to have a non-circular profile  752 . In the illustrated example, the dock mounting structure  750  includes a recessed portion  754  provided on the rear side  706  of the body  702 . The recessed portion  754  can be configured to have a periphery  756  that defines the non-circular profile  752 . In the illustrated example, the non-circular profile  752  includes generally semi-circular recesses at opposite ends (i.e., at or adjacent the first and second lateral sides  708  and  710  of the body  702 ) and a generally rectangular recess that extends between the opposite semi-circular recesses. Other shapes are also possible for the non-circular profile  752 , such as generally oval, elliptical, or polygonal shapes. 
     In some embodiments, the PMSA  500  includes the appliance connectors  760  configured to electrically connect to corresponding connectors of the docking device  502  and enable the PMSA  500  to interact with the docking device  502  for communicating data and/or electric power therebetween. The appliance connectors  760  can include a plurality of electrical contacts. In some embodiments, the appliance connectors  760  include spring-loaded pins, such as Pogo pins. In other embodiments, the appliance connectors  760  include electrical plates. 
     In some embodiments, the appliance connectors  760  are arranged in the dock mounting structure  750  so that, when the dock mounting structure  750  is mounted to the docking device  502 , the appliance connectors  760  are aligned with, and electrically connected to, corresponding connectors of the docking device  502 . In some embodiments, the appliance connectors  760  include a power input connector  772 , a media signal output connector  774 , and a docking identification connector  776 . 
     The power input connector  772  is configured to electrically connect with a corresponding connector of the docking device  502  and receive electric power from the docking device  502 . In some embodiments, the power input connector  772  includes a pair of electrical contacts for receiving electric power from the docking device  502  that can be connected to the power source of the vehicle. As described herein, the power input connector  772  can be used to charge one or more batteries in the PMSA  500  where the PMSA  500  includes such batteries. 
     The media signal output connector  774  is configured to electrically connect with a corresponding connector of the docking device  502  and transmit media content to the docking device  502 . In some embodiments, the PMSA  500  transmits the media content signal  164  ( FIG. 2 ) to the docking device  502  through the media signal output connector  774  so that the docking device  502  transmits the media content signal  164  to the vehicle media playback system  114  via, for example, the media content output line  550 . 
     The docking identification connector  776  is configured to electrically connect with a corresponding connector of the docking device  502  and enables the PMSA  500  to determine that the PMSA  500  is mounted to the docking device  502  in place and electrically connected to the docking device  502  properly. 
     Referring still to  FIG. 11 , the PMSA  500  can further include the appliance control interfaces  762 . In some embodiments, the appliance control interfaces  762  are arranged at the rear side  706  of the body  702 . In other embodiments, the appliance control interfaces  762  are arranged in the dock mounting structure  750 . 
     In some embodiments, the appliance control interfaces  762  include a power button  780 , a microphone mute button  782 , and a reset button  784 . The power button  780  is configured to receive a user input (e.g., a press action) and turn on or off the PMSA  500  based on the user input. The microphone mute button  782  is configured to receive a user input (e.g., a press action) and turn on or off operation of the microphones  740  based on the user input. The reset button  784  is configured to receive a user input (e.g., a press action) and reset or format the PMSA  500  based on the user input. 
       FIG. 12  is an exploded rear perspective view of the PMSA  500  of  FIG. 1 . In some embodiments, the body  702  of the PMSA  500  includes a front body cover  790  and a rear body cover  792  that is coupled to the front body cover  790 , thereby defining the interior space  712 . In some embodiments, the front body cover  790  and the rear body cover  792  can be fastened to each other using one or more fasteners  794 . In other embodiments, the front body cover  790  and the rear body cover  792  can be coupled in other methods, such as using adhesive. 
     The PMSA  500  includes at least one printed circuit board (PCB)  800  housed in the interior  712  of the body  702 . The PCB  800  is configured to support and electrically connect electronic components and/or electrical components that implement the device, elements, components, and systems of the PMSA  500 . For example, the PCB  800  is configured to include at least some of the devices of the PMSA  500  that are illustrated in  FIGS. 2 and 7 . 
     In some embodiments, the PMSA  500  includes an appliance magnetic attachment device  802  included in the interior space  712  of the body  702 . The appliance magnetic attachment device  802  can be arranged adjacent (e.g., underneath) the rear side  706  of the body  702 . The appliance magnetic attachment device  802  is configured to magnetically attract a corresponding magnetic device of the docking device  502  and thus cause the PMSA  500  to position and orient relative to the docking device  502  in a predetermined arrangement when the PMSA  500  is mounted to the docking device  502 . 
     In some embodiments, the appliance magnetic attachment device  802  includes one or more plates  804  made of one or more magnetic materials. In some embodiments, the appliance magnetic attachment device  802  includes one or more first magnetic plates  804 A with a polarity (e.g., north) and one or more second magnetic plates  804 B with an opposite polarity (e.g., south). In this example, the PMSA  500  includes three magnetic plates  804 A with “north” pole and two magnetic plates  804 B with “south” pole. 
     In some embodiments, the appliance magnetic attachment device  802  is arranged in the dock mounting structure  750  (e.g., underneath the rear side  706  of the body  702  where the dock mounting structure  750  is located) so that the appliance magnetic attachment device  802  is used along with the dock mounting structure  750  of the PMSA  500 . 
       FIG. 13  is another exploded rear perspective view of the PMSA  500  of  FIG. 1 . In  FIG. 13 , the PCB  800  is removed from an assembly received in the front body cover  790 . In some embodiments, the PMSA  500  includes one or more batteries  810  (as the power supply device  144 ) included in the interior space  712  of the body  702 . In this example, two batteries  810  are included in the interior space  712  of the body  702  and can be recharged and supply electric power to the PMSA  500 . 
       FIG. 14  is a front perspective view of an example of the docking device  502 . The docking device  502  can include a dock body  830  having a forward side  832  and a rearward side  834  opposite to the forward side  832 . In some embodiments, the docking device  502  includes an appliance coupling structure  840 , one or more dock connectors  850 , a power source input device  860 , and a media signal output device  870 . 
     As described herein, the docking device  502  is used together with the PMSA  500 . The docking device  502  is specifically designed to mount to a vehicle dashboard, a head unit, or other suitable locations of the vehicle. For example, the interface between the PMSA  500  and the docking device  502  is designed to prevent the PMSA  500  from rotating relative to the docking device  502  when the control elements (e.g., a rotary know and buttons) on the PMSA  500  are manipulated by a user. By way of example, the rear side of the PMSA  500  has a recess having a non-circular shape (e.g., hexagon, ellipse, etc.), and the front side of the docking device  502  is configured to have a corresponding non-circular shape, so that the front side of the docking device  502  is partially received into, and interlocked with, the rear side of the PMSA  500 . In addition or alternatively, the PMSA  500  and the docking device  502  can include magnetic materials at the interface so that they are magnetically coupled. 
     Referring to  FIG. 14 , the appliance coupling structure  840  is configured to engage the dock mounting structure  750  of the PMSA  500 . In some embodiments, the appliance coupling structure  840  is constructed to complementarily engage the non-circular profile  752  of the dock mounting structure  750  of the PMSA  500 , thereby forming a mechanical interface  560  ( FIG. 6 ) therebetween configured to resist a rotational force F ( FIG. 10 ) applied by a user upon a rotation of the control knob assembly  510 . 
     In some embodiments, the appliance coupling structure  840  includes a protruded portion  842  that forms on the forward side  832  of the dock body  830 . The protruded portion  842  is can be formed integrally with the dock body  830 . The protruded portion  842  is configured to engage the recessed portion  754  of the dock mounting structure  750 . In some embodiments, the protruded portion  842  has a periphery  846  that defines a non-circular profile  844  therearound. The non-circular profile  844  of the protruded portion  842  is configured to be complementary to the non-circular profile  752  of the dock mounting structure  750  of the PMSA  500 . For example, similar to the non-circular profile  752  of the dock mounting structure  750 , the non-circular profile  844  of the docking device  502  includes generally semi-circular protrusions at opposite ends (i.e., at or adjacent opposite lateral sides of the dock body  830 ) and a generally rectangular protrusion that extends between the opposite semi-circular protrusions. Other shapes are also possible for the non-circular profile  844 , such as generally oval, elliptical, or polygonal shapes. 
     In some embodiments, the docking device  502  includes one or more dock connectors  850 . The dock connectors  850  are arranged to align with the appliance connectors  760  of the PMSA  500  and electrically connect with the appliance connectors  760  so that the PMSA  500  and the docking device  502  interact with each other to transmit data and/or electric power therebetween, when the PMSA  500  is mounted to the docking device  502 . 
     The dock connectors  850  can include a plurality of electrical contacts  530 . In some embodiments, the dock connectors  850  include electrical plates that contact the spring-loaded pins of the appliance connectors  760  of the PMSA  500 . In other embodiments, the dock connectors  850  include spring-loaded pins, such as Pogo pins. 
     In some embodiments, the dock connectors  850  are arranged in the appliance coupling structure  840  so that, when the PMSA  500  is mounted to the docking device  502 , the appliance coupling structure  840  of the docking device  502  engages with the dock mounting structure  750  of the PMSA  500 , and the dock connectors  850  are aligned with, and electrically connected to, the corresponding appliance connectors  760  of the PMSA  500 . In some embodiments, the dock connectors  850  includes a power output connector  852 , a media signal input connector  854 , and a docking identification connector  856 . 
     The power output connector  852  is configured to be electrically connected to the power source input device  860  of the docking device  502  so that the docking device  502  receives electric power from the vehicle when the power source input device  860  is connected to the vehicle power supply  540  ( FIG. 6 ) of the vehicle  80 . The power output connector is arranged to electrically connect with the power input connector  772  of the PMSA  500  and configured to provide to the PMSA  500  the electric power that have been received from the vehicle  80 . 
     The media signal input connector  854  is arranged to electrically connect with the media signal output connector  774  of the PMSA  500 . The media signal input connector  854  is configured to receive media content (e.g., the media content signal  164  ( FIG. 2 )) from the PMSA  500  and transmit the media content to the vehicle media playback system  114  via the media signal output device  870 . 
     The docking identification connector  856  is arranged to electrically connect with the docking identification connector  776  of the PMSA  500  and enable the PMSA  500  to determine that the PMSA  500  is properly mounted to the docking device  502 . 
     Referring still to  FIG. 14 , the docking device  502  can further include the power source input device  860  and the media signal output device  870 . 
     As described herein, the PMSA  500  can be primarily powered by an external power supply, such as from the vehicle  80 . The power source input device  860  can be configured to be electrically connected to the power source of the vehicle, such as the vehicle power supply  540 . The power source input device  860  is configured to receive the electric power from the vehicle  80  and transmit the electric power to the PMSA  500  via the power output connector  852  of the docking device  502  and the power input connector  772  of the PMSA  500  that are mated when. 
     In some embodiments, the power source input device  860  includes the power receiving line  544  and the power connector  546 , as described with reference to  FIG. 6 . Various types of power connection can be used for the power connector  546 , such as a vehicle power outlet (e.g., 12V power outlet) or a USB outlet (as illustrated in  FIG. 14 ). 
     As illustrated herein, in some embodiments, the PMSA  500  is configured to transmit media content to the vehicle media playback system  114  so that the media content is played through the vehicle media playback system  114 . The media signal output device  870  is configured to be connected to the vehicle media playback system  114 . The media signal output device  870  is configured to receive media content from the PMSA  500  and transmit the media content to the vehicle media playback system  114  for playback. For example, the media content (e.g., the media content signal  164 ) is transmitted from the PMSA  500  to the docking device  502  via the media signal output connector  774  of the PMSA  500  and the media signal input connector  854  of the docking device  502  that are mated when the PMSA  500  is mounted to the docking device  502 . The media content is then transmitted to the vehicle media playback system  114  via the media signal output device  870 . 
     In some embodiments, the media signal output device  870  includes the media content output line  550  and the media output connector  552 , as described with reference to  FIG. 6 . Various types of audio signal connection can be used for the media output connector  552 , such as an auxiliary (AUX) outlet or a USB outlet (as illustrated in  FIG. 14 ). Where a USB connection is used, the power source input device  860  and the media signal output device  870  are integrated as a single USB cable and connector  872  so that the transmission of electric power and media content signal can be performed via a single USB cable and connector  872 . 
       FIG. 15  is a rear perspective view of the docking device  502  of  FIG. 14 . In some embodiments, the docking device  502  includes a vehicle mounting portion  880  configured to mount the docking device  502  to the vehicle  80 . In some embodiments, the vehicle mounting portion  880  is arranged at the rearward side  834  and opposite to the appliance coupling structure  840 . 
     The vehicle mounting portion  880  can be configured to securely attach to a structure of the vehicle  80  so that the docking device  502  remains attached to the structure of the vehicle  80  while the PMSA  500  can be repeatedly mounted to, and removed from, the docking device  502 . In some embodiments, the vehicle mounting portion  880  that is arranged to be opposite to the appliance coupling structure  840  can help convenient and secured attachment and detachment of the PMSA  500  relative to the docking device  502 . 
     The vehicle mounting portion  880  can be configured to attach to various locations of the vehicle  80 , such as the dashboard  82 , the head unit  84 , a window (e.g., windshield, side windows, etc.), dashboard air vent, CD player slot, or other suitable structure in the vehicle. The vehicle mounting portion  880  can be configured to attach to the vehicle  80  in various methods. In some embodiments, the vehicle mounting portion  880  can be attached to a structure of the vehicle  80  with adhesive, such as a adhesive tape. In other embodiments, the vehicle mounting portion  880  can be attached to a structure of the vehicle  80  using a car mount of various types, such as a windshield mount, a dashboard mount, an air vent mount, a CD player slot mount, and other suitable types of car mount. 
       FIG. 16  is an exploded rear perspective view of the docking device  502  of  FIG. 14 . In some embodiments, the dock body  830  of the docking device  502  includes a front body cover  890  and a rear body cover  892  that is coupled to the front body cover  890 . In some embodiments, the front body cover  890  and the rear body cover  892  can be fastened to each other using one or more fasteners  894 . In other embodiments, the front body cover  890  and the rear body cover  892  can be coupled in other methods, such as using adhesive. 
     The docking device  502  includes at least one printed circuit board (PCB)  896  housed in of the dock body  830 . The PCB  896  is configured to support and electrically connect electronic components and/or electrical components that implement the device, elements, components, and systems of the docking device  502 . 
     In some embodiments, the docking device  502  includes a dock magnetic attachment device  900  included in the dock body  830 . The dock magnetic attachment device  900  can be arranged adjacent (e.g., underneath) the forward side  832  of the dock body  830 . The dock magnetic attachment device  900  is configured to interact with the appliance magnetic attachment device  802  of the PMSA  500  to removably mount the PMSA  500  to the docking device  502 . The dock magnetic attachment device  900  is configured to magnetically attract the appliance magnetic attachment device  802  of the PMSA  500  and thus cause the PMSA  500  to position and orient relative to the docking device  502  in a predetermined arrangement when the PMSA  500  is mounted to the docking device  502 . 
     In some embodiments, the dock magnetic attachment device  900  includes one or more magnets  902 . In some embodiments, the dock magnetic attachment device  900  includes one or more first magnets  902 A with a polarity (e.g., south) and one or more second magnets  902 B with an opposite polarity (e.g., north). In this example, the docking device  502  includes three magnets  902 A with “south” pole and two magnets  902 B with “north” pole. 
     As illustrated, the magnets  902  are arranged to be generally aligned with the magnetic plates  804  of the PMSA  500  when the PMSA  500  is mounted to the docking device  502 . For example, the first magnets  902 A (e.g., south pole) are arranged to generally align with the first magnetic plates  804 A of the PMSA  500  and magnetically attract the first magnetic plates  804 A (e.g., north pole). Similarly, the second magnets  902 B (e.g., north pole) are arranged to generally align with the second magnetic plates  804 B of the PMSA  500  and magnetically attract the second magnetic plates  804 B (e.g., south pole). 
     In some embodiments, the dock magnetic attachment device  900  is arranged in the appliance coupling structure  840  (e.g., underneath the forward side  832  of the dock body  830  where the appliance coupling structure  840  is located) so that the dock magnetic attachment device  900  is used along with the appliance coupling structure  840  of the docking device  502 . 
     Although it is primarily described herein that the PMSA  500  includes magnetic plates and the docking device  502  includes magnets, it is possible in other embodiments that the PMSA  500  includes magnets while the docking device  502  includes magnetic plates, that both the PMSA  500  and the docking device  502  include magnets, or that both the PMSA  500  and the docking device  502  include magnetic plates. 
     The various examples and teachings described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made without following the examples and applications illustrated and described herein, and without departing from the true spirit and scope of the present disclosure.