Patent Publication Number: US-11024138-B2

Title: Adjustable alert tones and operational modes for audio/video recording and communication devices based upon user location

Description:
CROSS-REFERENCE TO A RELATED APPLICATIONS 
     This application claims priority to, and is a continuation of, U.S. Nonprovisional application Ser. No. 15/936,399, filed on Mar. 26, 2018, which claims priority to Provisional Application Ser. No. 62/477,977, filed on Mar. 28, 2017. The entire contents of the priority applications are hereby incorporated by reference in their entirety as if fully set forth. 
    
    
     TECHNICAL FIELD 
     The present embodiments relate to audio/video (A/V) recording and communication devices, including A/V recording and communication doorbell systems. In particular, the present embodiments relate to improvements in the functionality of A/V recording and communication devices that enhance the ability to set operational modes, notifications, and alert tones, and to take certain actions dependent upon the proximity of one or more users of such devices. 
     BACKGROUND 
     Home safety is a concern for many homeowners and renters. Those seeking to protect or monitor their homes often wish to have video and audio communications with visitors, for example, those visiting an external door or entryway. Audio/Video (A/V) recording and communication doorbell systems provide this functionality, and can also aid in crime detection and prevention. For example, audio and/or video captured by an A/V recording and communication doorbell can be uploaded to the cloud and recorded on a remote server. Subsequent review of the A/V footage can aid law enforcement in capturing perpetrators of home burglaries and other crimes. Further, the presence of an A/V recording and communication doorbell at the entrance to a home acts as a powerful deterrent against would-be burglars. 
     SUMMARY 
     The various embodiments of the present adjustable alert tones and operational modes for audio/video recording and communication devices based upon user location have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments as expressed by the claims that follow, their more prominent features now will be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the present embodiments provide the advantages described herein. 
     One aspect of the present embodiments includes the realization that in current audio/video (A/V) recording and communication devices (e.g., doorbells) other than the present embodiments, users of such devices would benefit from as great a flexibility as possible regarding their options for setting notifications and alert tones. Further, users would benefit from the capability to set different alert tones, and have their A/V recording and communication devices assume different operational modes, and thus perform different tasks, or provide different alerts, depending upon whether the user is present or absent from the home (or other location where the A/V recording and communication device is installed). Still further, users would benefit from the capability to set different operational modes when secondary users, such as a spouse or child, are home alone, and to receive different notifications and/or alert tones when their loved ones are home alone. 
     In a first aspect, a method and apparatus is provided, the apparatus comprising an audio/video (A/V) recording and communication device with which a method may be practiced, the method comprising setting a first operational mode for the A/V recording and communication device, determining whether a registered user of the A/V recording and communication device is within a predetermined proximity of the A/V recording and communication device and upon determining that the registered user of the A/V recording and communication device is not within the predetermined proximity of the A/V recording and communication device, setting a second operational mode for the A/V recording and communication device. 
     In another embodiment of the first aspect, determining whether the registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device comprises registering a wireless client device associated with the registered user to the A/V recording and communication device and determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In another embodiment of the first aspect, the wireless client device is at least one of a smartphone and a wearable device. 
     In another embodiment of the first aspect, determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device comprises determining a location of the A/V recording and communication device, receiving GPS (Global Positioning System) location information from the wireless client device, and using the GPS location information and the location of the A/V recording and communication device to determine whether the wireless client device is within the predetermined proximity. 
     In another embodiment of the first aspect, determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device comprises receiving, at the A/V recording and communication device, a signal from the wireless client device; and using the receipt of the signal to determine that the wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In another embodiment of the first aspect, wherein the A/V recording and communication device comprises a camera having a field of view and wherein determining whether the registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device comprises uploading first image data of the registered user to a database that is accessible to the A/V recording and communication device, receiving second image data of a person within the field of view of the camera, and determining, by comparing the first image data and the second image data, whether the person is the registered user. 
     In another embodiment of the first aspect, the second operational mode comprises a heightened security mode. 
     In another embodiment of the first aspect, the heightened security mode comprises setting the camera to continuously record video images and, upon detecting any motion in the field of view of the A/V recording and communication device, sending an alert to a wireless client device that causes the wireless client device to play an audible tone that is uniquely associated with a severity of the alert. 
     In a second aspect a method and apparatus is provided, the apparatus comprising an audio/video (A/V) recording and communication device with which a method may be practiced, the method comprising setting a first operational mode for the A/V recording and communication device, determining whether a primary registered user of the A/V recording and communication device is within a predetermined proximity of the A/V recording and communication device, determining whether at least one secondary registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device, and upon determining that the primary registered user is outside of the predetermined proximity and that the at least one secondary registered user is inside the predetermined proximity, setting a second operational mode for the A/V recording and communication device. 
     In an embodiment of the second aspect, determining whether the primary registered user and the at least one secondary registered user are within the predetermined proximity of the A/V recording and communication device comprises registering a first wireless client device associated with the primary registered user to the A/V recording and communication device, registering a second wireless client device associated with the at least one secondary registered user to the A/V recording and communication device, determining whether the first wireless client device is within the predetermined proximity of the A/V recording and communication device, and determining whether the second wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In another embodiment of the second aspect, at least one of the first wireless client device and the second wireless client device is a smartphone. 
     In another embodiment of the second aspect, the second wireless client device is a wearable device. 
     In another embodiment of the second aspect, determining whether the first wireless client device and the second wireless device are each within the predetermined proximity of the A/V recording and communication device comprises determining a location of the A/V recording and communication device, receiving GPS (Global Positioning System) location information from the first wireless client device, using the GPS location information from the first wireless client device and the location of the A/V recording and communication device to determine whether the first wireless client device is within the predetermined proximity, receiving GPS location information from the second wireless client device, and using the GPS location information from the second wireless client device and the location of the A/V recording and communication device to determine whether the second wireless client device is within the predetermined proximity. 
     In another embodiment of the second aspect, determining whether the first wireless client device and the second wireless client device are each within the predetermined proximity of the A/V recording and communication device comprises receiving, at the A/V recording and communication device, a first signal from the first wireless client device, and using the receipt of the first signal to determine that the first wireless client device is within the predetermined proximity of the A/V recording and communication device, receiving, at the A/V recording and communication device, a second signal from the second wireless client device, and using the receipt of the second signal to determine that the second wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In another embodiment of the second aspect, the A/V recording and communication device is a video doorbell that enables a visitor to actuate a doorbell to send a notification to a wireless client device, and the method further comprises upon determining that neither the primary registered user nor any secondary registered user are within the predetermined proximity of the A/V recording and communication device, setting a third operational mode for the A/V recording and communication device, and upon actuation of the doorbell, generating and transmitting a unique priority alert to a first wireless client device associated with the primary registered user. 
     In a third aspect an audio/video (A/V) recording and communication device apparatus is provided, comprising a camera configured to capture image data of an object within a field of view of the camera, a communication module, and a processing module operatively connected to the camera and to the communication module, the processing module comprising a processor and a camera application, wherein the camera application configures the processor to set a first operational mode for the A/V recording and communication device, determine whether a registered user of the A/V recording and communication device is within a predetermined proximity of the A/V recording and communication device, and upon determining that the registered user of the A/V recording and communication device is not within the predetermined proximity of the A/V recording and communication device, set a second operational mode for the A/V recording and communication device. 
     In a further embodiment of the third aspect, determining whether the registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device comprises registering a wireless client device associated with the registered user to the A/V recording and communication device, and determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In a further embodiment of the third aspect, the wireless client device is at least one of a smartphone and a wearable device. 
     In a further embodiment of the third aspect, determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device comprises determining the location of the A/V recording and communication device, receiving GPS (Global Positioning System) location information from the wireless client device and using the GPS location information and the location of the A/V recording and communication device to determine whether the wireless client device is within the predetermined proximity. 
     In a further embodiment of the third aspect, determining whether the wireless client device is within the predetermined proximity of the A/V recording and communication device comprises receiving, at the A/V recording and communication device, a signal from the wireless client device and using the receipt of the signal to determine that the wireless client device is within the predetermined proximity of the A/V recording and communication device. 
     In a further embodiment of the third aspect, determining whether the registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device comprises uploading first image data of the registered user to a database that is accessible to the A/V recording and communication device, receiving second image data of a person within the field of view of the camera, and determining, by comparing the first image data and the second image data, whether the person is the registered user. 
     In a further embodiment of the third aspect, the second operational mode comprises a heightened security mode. 
     In a further embodiment of the third aspect, the heightened security mode comprises setting the camera to continuously record video images and upon detecting any motion in a field of view of the A/V recording and communication device, sending an alert to a wireless client device that causes the wireless client device to play an audible tone that is uniquely associated with a severity of the alert. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various embodiments of the present adjustable alert tones and operational modes for audio/video recording and communication devices based upon user location now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious methods, apparatus, and systems enabling the setting of customized operating modes, notifications, alert tones, monitoring, video recording, and actions for audio/video recording and communication devices shown in the accompanying drawings, which are for illustrative purposes only, using geolocation and other techniques to customize the behavior of the devices based on the locations of one or more users of the devices. These drawings include the following figures, in which like numerals indicate like parts: 
         FIG. 1  is a functional block diagram illustrating one embodiment of a system including an A/V recording and communication device according to various aspects of the present disclosure; 
         FIG. 2  is a flowchart illustrating one embodiment of a process for streaming and storing A/V content from an A/V recording and communication doorbell system according to various aspects of the present disclosure; 
         FIG. 3  is a functional block diagram illustrating an embodiment of an A/V recording and communication doorbell system according to the present disclosure; 
         FIG. 4  is a front perspective view of an embodiment of an A/V recording and communication doorbell according to the present disclosure; 
         FIG. 5  is a rear perspective view of the A/V recording and communication doorbell of  FIG. 4 ; 
         FIG. 6  is a partially exploded front perspective view of the A/V recording and communication doorbell of  FIG. 4  showing the cover removed; 
         FIGS. 7, 8, and 9  are front perspective views of various internal components of the A/V recording and communication doorbell of  FIG. 4 ; 
         FIG. 10  is a right-side cross-sectional view of the A/V recording and communication doorbell of  FIG. 4  taken through the line  10 - 10  in  FIG. 4 ; 
         FIGS. 11-13  are rear perspective views of various internal components of the A/V recording and communication doorbell of  FIG. 4 ; 
         FIG. 14  is a front view of an A/V recording and communication device according to various aspects of the present disclosure; 
         FIG. 15  is a rear view of the A/V recording and communication device of  FIG. 14 ; 
         FIG. 16  is cross-sectional right side view of the A/V recording and communication device of  FIG. 14 ; 
         FIG. 17  is an exploded view of the A/V recording and communication device of  FIG. 14  and a mounting bracket; 
         FIG. 18  is a top view of a passive infrared sensor assembly according to various aspects of the present disclosure; 
         FIG. 19  is a front view of the passive infrared sensor assembly of  FIG. 18 ; 
         FIG. 20  is a top view of the passive infrared sensor assembly of  FIG. 18 , illustrating the fields of view of the passive infrared sensors according to various aspects of the present disclosure; 
         FIG. 21  is a functional block diagram of the components of the A/V recording and communication device of  FIG. 14 ; 
         FIG. 22  is a flowchart showing aspects of one embodiment of a method disclosed herein; 
         FIG. 23  is a flowchart showing certain steps in aspects of another embodiment of a method disclosed herein; 
         FIG. 24  is a sequence diagram illustrating communication signals sent and received among various devices according to various aspects of the present disclosure; 
         FIG. 25  is a functional block diagram of a client device on which the present embodiments may be implemented according to various aspects of the present disclosure; and 
         FIG. 26  is a functional block diagram of a general-purpose computing system on which the present embodiments may be implemented according to various aspects of present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description describes the present embodiments with reference to the drawings. In the drawings, reference numbers label elements of the present embodiments. These reference numbers are reproduced below in connection with the discussion of the corresponding drawing features. 
     The embodiments of the present adjustable alert tones and operational modes for audio/video recording and communication devices based upon user location are described below with reference to the figures. These figures, and their written descriptions, indicate that certain components of the apparatus are formed integrally, and certain other components are formed as separate pieces. Those of ordinary skill in the art will appreciate that components shown and described herein as being formed integrally may in alternative embodiments be formed as separate pieces. Those of ordinary skill in the art will further appreciate that components shown and described herein as being formed as separate pieces may in alternative embodiments be formed integrally. Further, as used herein the term integral describes a single unitary piece. 
     With reference to  FIG. 1 , the present embodiments include an audio/video (A/V) recording and communication device  100 . The A/V recording and communication device  100  may in some embodiments comprise a doorbell, and may be located near the entrance to a structure (not shown), such as a dwelling, a business, a storage facility, etc. The A/V recording and communication device  100  includes a camera  102 , a microphone  104 , and a speaker  106 . The camera  102  may comprise, for example, a high definition (HD) video camera, such as one capable of capturing video images at an image display resolution of 720p, or 1080p, or better. While not shown, the A/V recording and communication device  100  may also include other hardware and/or components, such as a housing, one or more motion sensors (and/or other types of sensors), a button, etc. The A/V recording and communication device  100  may further include similar componentry and/or functionality as the wireless communication doorbells described in US Patent Application Publication Nos. 2015/0022620 (application Ser. No. 14/499,828) and 2015/0022618 (application Ser. No. 14/334,922), both of which are incorporated herein by reference in their entireties as if fully set forth. 
     With further reference to  FIG. 1 , the A/V recording and communication device  100  communicates with a user&#39;s network  110 , which may be for example a wired and/or wireless network. If the user&#39;s network  110  is wireless, or includes a wireless component, the network  110  may be a Wi-Fi network compatible with the IEEE 802.11 standard and/or other wireless communication standard(s). The user&#39;s network  110  is connected to another network  112 , which may comprise, for example, the Internet and/or a public switched telephone network (PSTN). As described below, the A/V recording and communication device  100  may communicate with a user&#39;s client device  114  via the user&#39;s network  110  and the network  112  (Internet/PSTN). The user&#39;s client device  114  may comprise, for example, a mobile telephone (may also be referred to as a cellular telephone), such as a smartphone, a personal digital assistant (PDA), or another communication device. The user&#39;s client device  114  comprises a display (not shown) and related components capable of displaying streaming and/or recorded video images. The user&#39;s client device  114  may also comprise a speaker and related components capable of broadcasting streaming and/or recorded audio, and may also comprise a microphone. The A/V recording and communication device  100  may also communicate with one or more remote storage device(s)  116  (may be referred to interchangeably as “cloud storage device(s)”), one or more servers  118 , and/or a backend API (application programming interface)  120  via the user&#39;s network  110  and the network  112  (Internet/PSTN). While  FIG. 1  illustrates the storage device  116 , the server  118 , and the backend API  120  as components separate from the network  112 , it is to be understood that the storage device  116 , the server  118 , and/or the backend API  120  may be considered to be components of the network  112 . 
     The network  112  may be any wireless network or any wired network, or a combination thereof, configured to operatively couple the above-mentioned modules, devices, and systems as shown in  FIG. 1 . For example, the network  112  may include one or more of the following: a PSTN (public switched telephone network), the Internet, a local intranet, a PAN (Personal Area Network), a LAN (Local Area Network), a WAN (Wide Area Network), a MAN (Metropolitan Area Network), a virtual private network (VPN), a storage area network (SAN), a frame relay connection, an Advanced Intelligent Network (AIN) connection, a synchronous optical network (SONET) connection, a digital T1, T3, E1 or E3 line, a Digital Data Service (DDS) connection, a DSL (Digital Subscriber Line) connection, an Ethernet connection, an ISDN (Integrated Services Digital Network) line, a dial-up port such as a V.90, V.34, or V.34bis analog modem connection, a cable modem, an ATM (Asynchronous Transfer Mode) connection, or an FDDI (Fiber Distributed Data Interface) or CDDI (Copper Distributed Data Interface) connection. Furthermore, communications may also include links to any of a variety of wireless networks, including WAP (Wireless Application Protocol), GPRS (General Packet Radio Service), GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access), and/or OFDMA (Orthogonal Frequency Division Multiple Access) cellular phone networks, GPS (Global Positioning System), CDPD (cellular digital packet data), RIM (Research in Motion, Limited) duplex paging network, Bluetooth radio, or an IEEE 802.11-based radio frequency network. The network can further include or interface with any one or more of the following: RS-232 serial connection, IEEE-1394 (Firewire) connection, Fibre Channel connection, IrDA (infrared) port, SCSI (Small Computer Systems Interface) connection, USB (Universal Serial Bus) connection, or other wired or wireless, digital or analog, interface or connection, mesh or Digi® networking. 
     According to one or more aspects of the present embodiments, when a person (may be referred to interchangeably as “visitor”) arrives at the A/V recording and communication device  100 , the A/V recording and communication device  100  detects the visitor&#39;s presence and begins capturing video images within a field of view of the camera  102 . The A/V recording and communication device  100  may also capture audio through the microphone  104 . The A/V recording and communication device  100  may detect the visitor&#39;s presence by detecting motion using the camera  102  and/or a motion sensor, and/or by detecting that the visitor has depressed the front button on the A/V recording and communication device  100  (in embodiments in which the A/V recording and communication device  100  comprises a doorbell). 
     In response to the detection of the visitor, the A/V recording and communication device  100  sends an alert to the user&#39;s client device  114  ( FIG. 1 ) via the user&#39;s network  110  and the network  112 . The A/V recording and communication device  100  also sends streaming video, and may also send streaming audio, to the user&#39;s client device  114 . If the user answers the alert, two-way audio communication may then occur between the visitor and the user through the A/V recording and communication device  100  and the user&#39;s client device  114 . The user may view the visitor throughout the duration of the call, but the visitor cannot see the user (unless the A/V recording and communication device  100  includes a display, which it may in some embodiments). 
     The video images captured by the camera  102  of the A/V recording and communication device  100  (and the audio captured by the microphone  104 ) may be uploaded to the cloud and recorded on the remote storage device  116  ( FIG. 1 ). In some embodiments, the video and/or audio may be recorded on the remote storage device  116  even if the user chooses to ignore the alert sent to his or her client device  114 . 
     With further reference to  FIG. 1 , the system may further comprise a backend API  120  including one or more components. A backend API (application programming interface) may comprise, for example, a server (e.g. a real server, or a virtual machine, or a machine running in a cloud infrastructure as a service), or multiple servers networked together, exposing at least one API to client(s) accessing it. These servers may include components such as application servers (e.g. software servers), depending upon what other components are included, such as a caching layer, or database layers, or other components. A backend API may, for example, comprise many such applications, each of which communicate with one another using their public APIs. In some embodiments, the API backend may hold the bulk of the user data and offer the user management capabilities, leaving the clients to have very limited state. 
     The backend API  120  illustrated  FIG. 1  may include one or more APIs. An API is a set of routines, protocols, and tools for building software and applications. An API expresses a software component in terms of its operations, inputs, outputs, and underlying types, defining functionalities that are independent of their respective implementations, which allows definitions and implementations to vary without compromising the interface. Advantageously, an API may provide a programmer with access to an application&#39;s functionality without the programmer needing to modify the application itself, or even understand how the application works. An API may be for a web-based system, an operating system, or a database system, and it provides facilities to develop applications for that system using a given programming language. In addition to accessing databases or computer hardware like hard disk drives or video cards, an API can ease the work of programming GUI components. For example, an API can facilitate integration of new features into existing applications (a so-called “plug-in API”). An API can also assist otherwise distinct applications with sharing data, which can help to integrate and enhance the functionalities of the applications. 
     The backend API  120  illustrated in  FIG. 1  may further include one or more services (also referred to as network services). A network service is an application that provides data storage, manipulation, presentation, communication, and/or other capability. Network services are often implemented using a client-server architecture based on application-layer network protocols. Each service may be provided by a server component running on one or more computers (such as a dedicated server computer offering multiple services) and accessed via a network by client components running on other devices. However, the client and server components can both be run on the same machine. Clients and servers may have a user interface, and sometimes other hardware associated with them. 
       FIG. 2  is a flowchart illustrating a process for streaming and storing A/V content from an A/V recording and communication doorbell system according to various aspects of the present disclosure. At block B 200 , the A/V recording and communication device  100  detects the visitor&#39;s presence and begins capturing video images within a field of view of the camera  102 . The A/V recording and communication device  100  may also capture audio through the microphone  104 . As described above, the A/V recording and communication device  100  may detect the visitor&#39;s presence by detecting motion using the camera  102  and/or a motion sensor, and/or by detecting that the visitor has depressed the front button on the A/V recording and communication device  100  (in embodiments in which the A/V recording and communication device  100  comprises a doorbell). 
     At block B 202 , a communication module of the A/V recording and communication device  100  sends a connection request, via the user&#39;s network  110  and the network  112 , to a device in the network  112 . For example, the network device to which the request is sent may be a server such as the server  118 . The server  118  may comprise a computer program and/or a machine that waits for requests from other machines or software (clients) and responds to them. A server typically processes data. One purpose of a server is to share data and/or hardware and/or software resources among clients. This architecture is called the client-server model. The clients may run on the same computer or may connect to the server over a network. Examples of computing servers include database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. The term server may be construed broadly to include any computerized process that shares a resource to one or more client processes. 
     In response to the request, at block B 204  the network device may connect the A/V recording and communication device  100  to the user&#39;s client device  114  through the user&#39;s network  110  and the network  112 . At block B 206 , the A/V recording and communication device  100  may record available audio and/or video data using the camera  102 , the microphone  104 , and/or any other sensor available. At block B 208 , the audio and/or video data is transmitted (streamed) from the A/V recording and communication device  100  to the user&#39;s client device  114  via the user&#39;s network  110  and the network  112 . At block B 210 , the user may receive a notification on his or her client device  114  with a prompt to either accept or deny the call. 
     At block B 212 , the process determines whether the user has accepted or denied the call. If the user denies the notification, then the process advances to block B 214 , where the audio and/or video data is recorded and stored at a cloud server. The session then ends at block B 216  and the connection between the A/V recording and communication device  100  and the user&#39;s client device  114  is terminated. If, however, the user accepts the notification, then at block B 218  the user communicates with the visitor through the user&#39;s client device  114  while audio and/or video data captured by the camera  102 , the microphone  104 , and/or other sensors is streamed to the user&#39;s client device  114 . At the end of the call, the user may terminate the connection between the user&#39;s client device  114  and the A/V recording and communication device  100  and the session ends at block B 216 . In some embodiments, the audio and/or video data may be recorded and stored at a cloud server (block B 214 ) even if the user accepts the notification and communicates with the visitor through the user&#39;s client device  114 . 
     Many of today&#39;s homes include a wired doorbell system that does not have A/V communication capabilities. Instead, standard wired doorbell systems include a button outside the home next to the front door. The button activates a signaling device (such as a bell or a buzzer) inside the building. Pressing the doorbell button momentarily closes the doorbell circuit, which may be, for example, a single-pole, single-throw (SPST) push button switch. One terminal of the button is wired to a terminal on a transformer. The transformer steps down the 120-volt or 240-volt household AC electrical power to a lower voltage, typically 16 to 24 volts. Another terminal on the transformer is wired to a terminal on the signaling device. Another terminal on the signaling device is wired to the other terminal on the button. A common signaling device includes two flat metal bar resonators, which are struck by plungers operated by two solenoids. The flat bars are tuned to different notes. When the doorbell button is pressed, the first solenoid&#39;s plunger strikes one of the bars, and when the button is released, a spring on the plunger pushes the plunger up, causing it to strike the other bar, creating a two-tone sound (“ding-dong”). 
     Many current A/V recording and communication doorbell systems (other than the present embodiments) are incompatible with existing wired doorbell systems of the type described in the preceding paragraph. One reason for this incompatibility is that the A/V recording and communication doorbell draws an amount of power from the household AC electrical power supply that is above the threshold necessary for causing the signaling device to sound. The A/V recording and communication doorbell thus causes frequent inadvertent sounding of the signaling device, which is not only bothersome to the home&#39;s occupant(s), but also undermines the usefulness of the doorbell. The present embodiments solve this problem by limiting the power consumption of the A/V recording and communication doorbell to an amount that is below the threshold necessary for causing the signaling device to sound. Embodiments of the present A/V recording and communication doorbell can thus be connected to the existing household AC power supply and the existing signaling device without causing inadvertent sounding of the signaling device. 
     Several advantages flow from the ability of the present embodiments to be connected to the existing household AC power supply. For example, the camera of the present A/V recording and communication doorbell can be powered on continuously. In a typical battery-powered A/V recording and communication doorbell, the camera is powered on only part of the time so that the battery does not drain too rapidly. The present embodiments, by contrast, do not rely on a battery as a primary (or sole) power supply, and are thus able to keep the camera powered on continuously. Because the camera is able to be powered on continuously, it can always be recording, and recorded footage can be continuously stored in a rolling buffer or sliding window. In some embodiments, about 10-15 seconds of recorded footage can be continuously stored in the rolling buffer or sliding window. Also because the camera is able to be powered on continuously, it can be used for motion detection, thus eliminating any need for a separate motion detection device, such as a passive infrared sensor (PIR). Eliminating the PIR simplifies the design of the A/V recording and communication doorbell and enables the doorbell to be made more compact. Also because the camera is able to be powered on continuously, it can be used as a light sensor for use in controlling the current state of the IR cut filter and turning the IR LED on and off. Using the camera as a light sensor eliminates any need for a separate light sensor, thereby further simplifying the design of the A/V recording and communication doorbell and enabling the doorbell to be made even more compact. 
       FIGS. 3-13  illustrate one embodiment of a low-power-consumption A/V recording and communication doorbell  130  according to various aspects of the present disclosure.  FIG. 3  is a functional block diagram illustrating various components of the A/V recording and communication doorbell  130  and their relationships to one another. For example, the A/V recording and communication doorbell  130  includes a pair of terminals  131 ,  132  configured to be connected to a source of external AC (alternating-current) power, such as a household AC power supply  134  (may also be referred to as AC mains). The AC power  134  may have a voltage in the range of 16-24 VAC, for example. The incoming AC power  134  may be converted to DC (direct-current) by an AC/DC rectifier  136 . An output of the AC/DC rectifier  136  may be connected to an input of a DC/DC converter  138 , which may step down the voltage from the output of the AC/DC rectifier  136  from 16-24 VDC to a lower voltage of about 5 VDC, for example. In various embodiments, the output of the DC/DC converter  138  may be in a range of from about 2.5 V to about 7.5 V, for example. 
     With further reference to  FIG. 3 , the output of the DC/DC converter  138  is connected to a power manager  140 , which may comprise an integrated circuit including a processor core, memory, and/or programmable input/output peripherals. In one non-limiting example, the power manager  140  may be an off-the-shelf component, such as the BQ24773 chip manufactured by Texas Instruments. As described in detail below, the power manager  140  controls, among other things, an amount of power drawn from the external power supply  134 , as well as an amount of supplemental power drawn from a battery  142 , to power the A/V recording and communication doorbell  130 . The power manager  140  may, for example, limit the amount of power drawn from the external power supply  134  so that a threshold power draw is not exceeded. In one non-limiting example, the threshold power, as measured at the output of the DC/DC converter  138 , may be equal to 1.4 A. The power manager  140  may also control an amount of power drawn from the external power supply  134  and directed to the battery  142  for recharging of the battery  142 . An output of the power manager  140  is connected to a power sequencer  144 , which controls a sequence of power delivery to other components of the A/V recording and communication doorbell  130 , including a communication module  146 , a front button  148 , a microphone  150 , a speaker driver  151 , a speaker  152 , an audio CODEC (Coder-DECoder)  153 , a camera  154 , an infrared (IR) light source  156 , an IR cut filter  158 , a processor  160  (may also be referred to as a controller  160 ), a plurality of light indicators  162 , and a controller  164  for the light indicators  162 . Each of these components is described in detail below. The power sequencer  144  may comprise an integrated circuit including a processor core, memory, and/or programmable input/output peripherals. In one non-limiting example, the power sequencer  144  may be an off-the-shelf component, such as the RT5024 chip manufactured by Richtek. 
     With further reference to  FIG. 3 , the A/V recording and communication doorbell  130  further comprises an electronic switch  166  that closes when the front button  148  is depressed. When the electronic switch  166  closes, power from the AC power source  134  is diverted through a signaling device  168  that is external to the A/V recording and communication doorbell  130  to cause the signaling device  168  to emit a sound, as further described below. In one non-limiting example, the electronic switch  166  may be a triac device. The A/V recording and communication doorbell  130  further comprises a reset button  170  configured to initiate a hard reset of the processor  160 , as further described below. 
     With further reference to  FIG. 3 , the processor  160  may perform data processing and various other functions, as described below. The processor  160  may comprise an integrated circuit including a processor core, memory  172 , non-volatile memory  174 , and/or programmable input/output peripherals (not shown). The memory  172  may comprise, for example, DDR3 (double data rate type three synchronous dynamic random-access memory). The non-volatile memory  174  may comprise, for example, NAND flash memory. In the embodiment illustrated in  FIG. 3 , the memory  172  and the non-volatile memory  174  are illustrated within the box representing the processor  160 . It is to be understood that the embodiment illustrated in  FIG. 3  is merely an example, and in some embodiments the memory  172  and/or the non-volatile memory  174  are not necessarily physically incorporated with the processor  160 . The memory  172  and/or the non-volatile memory  174 , regardless of their physical location, may be shared by one or more other components (in addition to the processor  160 ) of the present A/V recording and communication doorbell  130 . 
     The transfer of digital audio between the user and a visitor may be compressed and decompressed using the audio CODEC  153 , which is operatively coupled to the processor  160 . When the visitor speaks, audio from the visitor is compressed by the audio CODEC  153 , digital audio data is sent through the communication module  146  to the network  112  via the user&#39;s network  110 , routed by the server  118  and delivered to the user&#39;s client device  114 . When the user speaks, after being transferred through the network  112 , the user&#39;s network  110 , and the communication module  146 , the digital audio data is decompressed by the audio CODEC  153  and emitted to the visitor through the speaker  152 , which is driven by the speaker driver  151 . 
     With further reference to  FIG. 3 , some of the present embodiments may include a shunt  176  connected in parallel with the signaling device  168 . The shunt  176  facilitates the ability of the A/V recording and communication doorbell  130  to draw power from the AC power source  134  without inadvertently triggering the signaling device  168 . The shunt  176 , during normal standby operation, presents a relatively low electrical impedance, such as a few ohms, across the terminals of the signaling device  168 . Most of the current drawn by the A/V recording and communication doorbell  130 , therefore, flows through the shunt  176 , and not through the signaling device  168 . The shunt  176 , however, contains electronic circuitry (described below) that switches the shunt  176  between a state of low impedance, such as a few ohms, for example, and a state of high impedance, such as &gt;1K ohms, for example. When the front button  148  of the A/V recording and communication doorbell  130  is pressed, the electronic switch  166  closes, causing the voltage from the AC power source  134  to be impressed mostly across the shunt  176  and the signaling device  168  in parallel, while a small amount of voltage, such as about 1V, is impressed across the electronic switch  166 . The circuitry in the shunt  176  senses this voltage, and switches the shunt  176  to the high impedance state, so that power from the AC power source  134  is diverted through the signaling device  168 . The diverted AC power  134  is above the threshold necessary to cause the signaling device  168  to emit a sound. Pressing the front button  148  of the doorbell  130  therefore causes the signaling device  168  to sound, alerting any person(s) within the structure to which the doorbell  130  is mounted that there is a visitor at the front door (or at another location corresponding to the location of the doorbell  130 ). In one non-limiting example, the electronic switch  166  may be a triac device. 
     With reference to  FIGS. 4-6 , the A/V recording and communication doorbell  130  further comprises a housing  178  having an enclosure  180  ( FIG. 6 ), a back plate  182  secured to the rear of the enclosure  180 , and a shell  184  overlying the enclosure  180 . With reference to  FIG. 6 , the shell  184  includes a recess  186  that is sized and shaped to receive the enclosure  180  in a close fitting engagement, such that outer surfaces of the enclosure  180  abut conforming inner surfaces of the shell  184 . Exterior dimensions of the enclosure  180  may be closely matched with interior dimensions of the shell  184  such that friction maintains the shell  184  about the enclosure  180 . Alternatively, or in addition, the enclosure  180  and/or the shell  184  may include mating features  188 , such as one or more tabs, grooves, slots, posts, etc. to assist in maintaining the shell  184  about the enclosure  180 . The back plate  182  is sized and shaped such that the edges of the back plate  182  extend outward from the edges of the enclosure  180 , thereby creating a lip  190  against which the shell  184  abuts when the shell  184  is mated with the enclosure  180 , as shown in  FIGS. 4 and 5 . In some embodiments, multiple shells  184  in different colors may be provided so that the end user may customize the appearance of his or her A/V recording and communication doorbell  130 . For example, the A/V recording and communication doorbell  130  may be packaged and sold with multiple shells  184  in different colors in the same package. 
     With reference to  FIG. 4 , a front surface of the A/V recording and communication doorbell  130  includes the button  148  (may also be referred to as front button  148 ,  FIG. 3 ), which is operatively connected to the processor  160 . In a process similar to that described above with reference to  FIG. 2 , when a visitor presses the front button  148 , an alert may be sent to the user&#39;s client device to notify the user that someone is at his or her front door (or at another location corresponding to the location of the A/V recording and communication doorbell  130 ). With further reference to  FIG. 4 , the A/V recording and communication doorbell  130  further includes the camera  154 , which is operatively connected to the processor  160 , and which is located behind a shield  192 . As described in detail below, the camera  154  is configured to capture video images from within its field of view. Those video images can be streamed to the user&#39;s client device and/or uploaded to a remote network device for later viewing according to a process similar to that described above with reference to  FIG. 2 . 
     With reference to  FIG. 5 , a pair of terminal screws  194  extends through the back plate  182 . The terminal screws  194  are connected at their inner ends to the terminals  131 ,  132  ( FIG. 3 ) within the A/V recording and communication doorbell  130 . The terminal screws  194  are configured to receive electrical wires to connect to the A/V recording and communication doorbell  130 , through the terminals  131 ,  132 , to the household AC power supply  134  of the structure on which the A/V recording and communication doorbell  130  is mounted. In the illustrated embodiment, the terminal screws  194  are located within a recessed portion  196  of the rear surface  198  of the back plate  182  so that the terminal screws  194  do not protrude from the outer envelope of the A/V recording and communication doorbell  130 . The A/V recording and communication doorbell  130  can thus be mounted to a mounting surface with the rear surface  198  of the back plate  182  abutting the mounting surface. The back plate  182  includes apertures  200  adjacent its upper and lower edges to accommodate mounting hardware, such as screws (not shown), for securing the back plate  182  (and thus the A/V recording and communication doorbell  130 ) to the mounting surface. With reference to  FIG. 6 , the enclosure  180  includes corresponding apertures  202  adjacent its upper and lower edges that align with the apertures  200  in the back plate  182  to accommodate the mounting hardware. In certain embodiments, the A/V recording and communication doorbell  130  may include a mounting plate or bracket (not shown) to facilitate securing the A/V recording and communication doorbell  130  to the mounting surface. 
     With further reference to  FIG. 6 , the shell  184  includes a central opening  204  in a front surface. The central opening  204  is sized and shaped to accommodate the shield  192 . In the illustrated embodiment, the shield  192  is substantially rectangular, and includes a central opening  206  through which the front button  148  protrudes. The shield  192  defines a plane parallel to and in front of a front surface  208  of the enclosure  180 . When the shell  184  is mated with the enclosure  180 , as shown in  FIGS. 4 and 10 , the shield  192  resides within the central opening  204  of the shell  184  such that a front surface  210  of the shield  192  is substantially flush with a front surface  212  of the shell  184  and there is little or no gap ( FIG. 4 ) between the outer edges of the shield  192  and the inner edges of the central opening  204  in the shell  184 . 
     With further reference to  FIG. 6 , the shield  192  includes an upper portion  214  (located above and to the sides of the front button  148 ) and a lower portion  216  (located below and to the sides of the front button  148 ). The upper and lower portions  214 ,  216  of the shield  192  may be separate pieces, and may comprise different materials. The upper portion  214  of the shield  192  may be transparent or translucent so that it does not interfere with the field of view of the camera  154 . For example, in certain embodiments the upper portion  214  of the shield  192  may comprise glass or plastic. As described in detail below, the microphone  150 , which is operatively connected to the processor  160 , is located behind the upper portion  214  of the shield  192 . The upper portion  214 , therefore, may include an opening  218  that facilitates the passage of sound through the shield  192  so that the microphone  150  is better able to pick up sounds from the area around the A/V recording and communication doorbell  130 . 
     The lower portion  216  of the shield  192  may comprise a material that is substantially transparent to infrared (IR) light, but partially or mostly opaque with respect to light in the visible spectrum. For example, in certain embodiments the lower portion  216  of the shield  192  may comprise a plastic, such as polycarbonate. The lower portion  216  of the shield  192 , therefore, does not interfere with transmission of IR light from the IR light source  156 , which is located behind the lower portion  216 . As described in detail below, the IR light source  156  and the IR cut filter  158 , which are both operatively connected to the processor  160 , facilitate night vision functionality of the camera  154 . 
     The upper portion  214  and/or the lower portion  216  of the shield  192  may abut an underlying cover  220  ( FIG. 10 ), which may be integral with the enclosure  180  or may be a separate piece. The cover  220 , which may be opaque, may include a first opening  222  corresponding to the location of the camera  154 , a second opening (not shown) corresponding to the location of the microphone  150  and the opening  218  in the upper portion  214  of the shield  192 , and a third opening (not shown) corresponding to the location of the IR light source  156 . 
       FIGS. 7-10  illustrate various internal components of the A/V recording and communication doorbell  130 .  FIGS. 7-9  are front perspective views of the doorbell  130  with the shell  184  and the enclosure  180  removed, while  FIG. 10  is a right-side cross-sectional view of the doorbell  130  taken through the line  10 - 10  in  FIG. 4 . With reference to  FIGS. 7 and 8 , the A/V recording and communication doorbell  130  further comprises a main printed circuit board (PCB)  224  and a front PCB  226 . With reference to  FIG. 8 , the front PCB  226  comprises a button actuator  228 . With reference to  FIGS. 7, 8, and 10 , the front button  148  is located in front of the button actuator  228 . The front button  148  includes a stem  230  ( FIG. 10 ) that extends into the housing  178  to contact the button actuator  228 . When the front button  148  is pressed, the stem  230  depresses the button actuator  228 , thereby closing the electronic switch  166  ( FIG. 8 ), as described below. 
     With reference to  FIG. 8 , the front PCB  226  further comprises the light indicators  162 , which may illuminate when the front button  148  of the doorbell  130  is pressed. In the illustrated embodiment, the light indicators  162  comprise light-emitting diodes (LEDs  162 ) that are surface mounted to the front surface of the front PCB  226  and are arranged in a circle around the button actuator  228 . The present embodiments are not limited to the light indicators  162  being LEDs, and in alternative embodiments the light indicators  162  may comprise any other type of light-emitting device. The present embodiments are also not limited by the number of light indicators  162  shown in  FIG. 8 , nor by the pattern in which they are arranged. 
     With reference to  FIG. 7 , the doorbell  130  further comprises a light pipe  232 . The light pipe  232  is a transparent or translucent ring that encircles the front button  148 . With reference to  FIG. 4 , the light pipe  232  resides in an annular space between the front button  148  and the central opening  206  in the shield  192 , with a front surface  234  of the light pipe  232  being substantially flush with the front surface  210  of the shield  192 . With reference to  FIGS. 7 and 10 , a rear portion of light pipe  232  includes a plurality of posts  236  whose positions correspond to the positions of the LEDs  162 . When the LEDs  162  are illuminated, light is transmitted through the posts  236  and the body of the light pipe  232  so that the light is visible at the front surface  234  of the light pipe  232 . The LEDs  162  and the light pipe  232  thus provide a ring of illumination around the front button  148 . The light pipe  232  may comprise a plastic, for example, or any other suitable material capable of transmitting light. 
     The LEDs  162  and the light pipe  232  may function as visual indicators for a visitor and/or a user. For example, the LEDs  162  may illuminate upon activation or stay illuminated continuously. In one aspect, the LEDs  162  may change color to indicate that the front button  148  has been pressed. The LEDs  162  may also indicate that the battery  142  needs recharging, or that the battery  142  is currently being charged, or that charging of the battery  142  has been completed. The LEDs  162  may indicate that a connection to the user&#39;s wireless network is good, limited, poor, or not connected. The LEDs  162  may be used to guide the user through setup or installation steps using visual cues, potentially coupled with audio cues emitted from the speaker  152 . 
     With further reference to  FIG. 7 , the A/V recording and communication doorbell  130  further comprises a rechargeable battery  142 . As described in further detail below, the A/V recording and communication doorbell  130  is connected to an external power source  134  ( FIG. 3 ), such as AC mains. The A/V recording and communication doorbell  130  is primarily powered by the external power source  134 , but may also draw power from the rechargeable battery  142  so as not to exceed a threshold amount of power from the external power source  134 , to thereby avoid inadvertently sounding the signaling device  168 . With reference to  FIG. 3 , the battery  142  is operatively connected to the power manager  140 . As described below, the power manager  140  controls an amount of power drawn from the battery  142  to supplement the power drawn from the external AC power source  134  to power the A/V recording and communication doorbell  130  when supplemental power is needed. The power manager  140  also controls recharging of the battery  142  using power drawn from the external power source  134 . The battery  142  may comprise, for example, a lithium-ion battery, or any other type of rechargeable battery. 
     With further reference to  FIG. 7 , the A/V recording and communication doorbell  130  further comprises the camera  154 . The camera  154  is coupled to a front surface of the front PCB  226 , and includes a lens  238  and an imaging processor  240  ( FIG. 9 ). The camera lens  238  may be a lens capable of focusing light into the camera  154  so that clear images may be captured. The camera  154  may comprise, for example, a high definition (HD) video camera, such as one capable of capturing video images at an image display resolution of 720p or better. In certain of the present embodiments, the camera  154  may be used to detect motion within its field of view, as described below. 
     With further reference to  FIG. 7 , the A/V recording and communication doorbell  130  further comprises an infrared (IR) light source  242 . In the illustrated embodiment, the IR light source  242  comprises an IR light-emitting diode (LED)  242  coupled to an IR LED printed circuit board (PCB)  244 . In alternative embodiments, the IR LED  242  may not comprise a separate PCB  244 , and may, for example, be coupled to the front PCB  226 . 
     With reference to  FIGS. 7 and 10 , the IR LED PCB  244  is located below the front button  148  ( FIG. 7 ) and behind the lower portion  216  of the shield  192  ( FIG. 10 ). As described above, the lower portion  216  of the shield  192  is transparent to IR light, but may be opaque with respect to light in the visible spectrum. 
     The IR LED  242  may be triggered to activate when a low level of ambient light is detected. When activated, IR light emitted from the IR LED  242  illuminates the camera  154 &#39;s field of view. The camera  154 , which may be configured to detect IR light, may then capture the IR light emitted by the IR LED  242  as it reflects off objects within the camera  154 &#39;s field of view, so that the A/V recording and communication doorbell  130  can clearly capture images at night (may be referred to as “night vision”). 
     With reference to  FIG. 9 , the A/V recording and communication doorbell  130  further comprises an IR cut filter  158 . The IR cut filter  158  is a mechanical shutter that can be selectively positioned between the lens  238  and the image sensor of the camera  154 . During daylight hours, or whenever there is a sufficient amount of ambient light, the IR cut filter  158  is positioned between the lens  238  and the image sensor to filter out IR light so that it does not distort the colors of images as the human eye sees them. During nighttime hours, or whenever there is little to no ambient light, the IR cut filter  158  is withdrawn from the space between the lens  238  and the image sensor, so that the camera  154  is sensitive to IR light (night vision). In some embodiments, the camera  154  acts as a light sensor for use in controlling the current state of the IR cut filter  158  and turning the IR LED  242  on and off. Using the camera  154  as a light sensor is facilitated in some embodiments by the fact that the A/V recording and communication doorbell  130  is powered by a connection to AC mains, and the camera  154 , therefore, is always powered on. In other embodiments, however, the A/V recording and communication doorbell  130  may include a light sensor separate from the camera  154  for use in controlling the IR cut filter  158  and the IR LED  242 . 
     With reference back to  FIG. 6 , the A/V recording and communication doorbell  130  further comprises a reset button  170 . The reset button  170  contacts a reset button actuator  246  ( FIG. 8 ) coupled to the front PCB  226 . When the reset button  170  is pressed, it may contact the reset button actuator  246 , which may trigger the erasing of any data stored at the non-volatile memory  174  and/or at the memory  172  ( FIG. 3 ), and/or may trigger a reboot of the processor  160 . 
       FIGS. 11-13  further illustrate internal components of the A/V recording and communication doorbell  130 .  FIGS. 11-13  are rear perspective views of the doorbell  130  with the back plate  182  and additional components removed. For example, in  FIG. 11  the back plate  182  is removed, while in  FIG. 12  the back plate  182  and the main PCB  224  are removed, and in  FIG. 13  the back plate  182 , the main PCB  224 , and the front PCB  226  are removed. With reference to  FIG. 11 , several components are coupled to the rear surface of the main PCB  224 , including the communication module  146 , the processor  160 , memory  172 , and non-volatile memory  174 . The functions of each of these components are described below. With reference to  FIG. 12 , several components are coupled to the rear surface of the front PCB  226 , including the power manager  140 , the power sequencer  144 , the AC/DC rectifier  136 , the DC/DC converter  138 , and the controller  164  for the light indicators  162 . The functions of each of these components are also described below. With reference to  FIG. 13 , several components are visible within the enclosure  180 , including the microphone  150 , a speaker chamber  248  (in which the speaker  152  is located), and an antenna  250  for the communication module  146 . The functions of each of these components are also described below. 
     With reference to  FIG. 7 , the antenna  250  is coupled to the front surface of the main PCB  224  and operatively connected to the communication module  146 , which is coupled to the rear surface of the main PCB  224  ( FIG. 11 ). The microphone  150 , which may also be coupled to the front surface of the main PCB  224 , is located near the opening  218  ( FIG. 4 ) in the upper portion  214  of the shield  192  so that sounds emanating from the area around the A/V recording and communication doorbell  130  can pass through the opening  218  and be detected by the microphone  150 . With reference to  FIG. 13 , the speaker chamber  248  is located near the bottom of the enclosure  180 . The speaker chamber  248  comprises a hollow enclosure in which the speaker  152  is located. The hollow speaker chamber  248  amplifies the sounds made by the speaker  152  so that they can be better heard by a visitor in the area near the A/V recording and communication doorbell  130 . With reference to  FIGS. 5 and 13 , the lower surface  252  of the shell  184  and the lower surface (not shown) of the enclosure  180  may include an acoustical opening  254  through which the sounds made by the speaker  152  can pass so that they can be better heard by a visitor in the area near the A/V recording and communication doorbell  130 . In the illustrated embodiment, the acoustical opening  254  is shaped generally as a rectangle having a length extending substantially across the lower surface  252  of the shell  184  (and also the enclosure  180 ). The illustrated shape is, however, just one example. With reference to  FIG. 5 , the lower surface  252  of the shell  184  may further include an opening  256  for receiving a security screw (not shown). The security screw may extend through the opening  256  and into a similarly located opening in the enclosure  180  to secure the shell  184  to the enclosure  180 . If the doorbell  130  is mounted to a mounting bracket (not shown), the security screw may also maintain the doorbell  130  on the mounting bracket. 
     With reference to  FIG. 13 , the A/V recording and communication doorbell  130  may further include a battery heater  258 . The present A/V recording and communication doorbell  130  is configured for outdoor use, including in cold climates. Cold temperatures, however, can cause negative performance issues for rechargeable batteries, such as reduced energy capacity, increased internal resistance, reduced ability to charge without damage, and reduced ability to supply load current. The battery heater  258  helps to keep the rechargeable battery  142  warm in order to reduce or eliminate the foregoing negative performance issues. In the illustrated embodiment, the battery heater  258  comprises a substantially flat, thin sheet abutting a side surface of the rechargeable battery  142 . The battery heater  258  may comprise, for example, an electrically resistive heating element that produces heat when electrical current is passed through it. The battery heater  258  may thus be operatively coupled to the power manager  140  and/or the power sequencer  144  ( FIG. 12 ). In some embodiments, the rechargeable battery  142  may include a thermally sensitive resistor (“thermistor,” not shown) operatively connected to the processor  160  so that the battery  142 &#39;s temperature can be monitored and the amount of power supplied to the battery heater  258  can be adaptively controlled to keep the rechargeable battery  142  within a desired temperature range. 
     As described above, the present embodiments advantageously limit the power consumption of the A/V recording and communication doorbell to an amount that is below the threshold necessary for causing the signaling device to sound (except when the front button of the doorbell is pressed). The present A/V recording and communication doorbell can thus be connected to the existing household AC power supply and the existing signaling device without causing inadvertent sounding of the signaling device. 
     Several advantages flow from the ability of the present embodiments to be connected to the existing household AC power supply. For example, the camera of the present A/V recording and communication doorbell can be powered on continuously. In a typical battery-powered A/V recording and communication doorbell, the camera is powered on only part of the time so that the battery does not drain too rapidly. The present embodiments, by contrast, do not rely on a battery as a primary (or sole) power supply, and are thus able to keep the camera powered on continuously. Because the camera is able to be powered on continuously, it can always be recording, and recorded footage can be continuously stored in a rolling buffer or sliding window. In some embodiments, about 10-15 seconds of recorded footage can be continuously stored in the rolling buffer or sliding window. Also because the camera is able to be powered on continuously, it can be used for motion detection, thus eliminating any need for a separate motion detection device, such as a passive infrared sensor (PIR). Eliminating the PIR simplifies the design of the A/V recording and communication doorbell and enables the doorbell to be made more compact, although in some alternative embodiments the doorbell may include one or more PIRs and/or other motion sensors, heat source sensors, etc. Also because the camera is able to be powered on continuously, it can be used as a light sensor for use in controlling the current state of the IR cut filter and turning the IR LED on and off. Using the camera as a light sensor eliminates any need for a separate light sensor, thereby further simplifying the design of the A/V recording and communication doorbell and enabling the doorbell to be made even more compact, although in some alternative embodiments the doorbell may include a separate light sensor. 
       FIGS. 14-18  illustrate another embodiment of a wireless audio/video (A/V) communication doorbell  330  according to an aspect of present embodiments.  FIG. 14  is a front view,  FIG. 15  is a rear view,  FIG. 16  is a right-side cross-sectional view, and  FIG. 17  is an exploded view of the doorbell  330  and a mounting bracket  337 . As described below, the doorbell  330  is configured to be connected to an external power source, such as household wiring, but is also configured to be powered by an on-board rechargeable battery instead of, or in addition to, the external power source. 
     The doorbell  330  includes a faceplate  335  mounted to a back plate  339  ( FIG. 15 ). With reference to  FIG. 16 , the faceplate  335  has a substantially flat profile. The faceplate  335  may comprise any suitable material, including, without limitation, metals, such as brushed aluminum or stainless steel, metal alloys, or plastics. The faceplate  335  protects the internal contents of the doorbell  330  and serves as an exterior front surface of the doorbell  330 . 
     With reference to  FIG. 14 , the faceplate  335  includes a button  333  and a light pipe  336 . The button  333  and the light pipe  336  may have various profiles that may or may not match the profile of the faceplate  335 . The light pipe  336  may comprise any suitable material, including, without limitation, transparent plastic, that is capable of allowing light produced within the doorbell  330  to pass through. The light may be produced by one or more light-emitting components, such as light-emitting diodes (LED&#39;s), contained within the doorbell  330 , as further described below. The button  333  may make contact with a button actuator (not shown) located within the doorbell  330  when the button  333  is pressed by a visitor. When pressed, the button  333  may trigger one or more functions of the doorbell  330 , as further described below. 
     With reference to  FIGS. 3 and 4 , the doorbell  330  further includes an enclosure  331  that engages the faceplate  335 . In the illustrated embodiment, the enclosure  331  abuts an upper edge  335 T ( FIG. 14 ) of the faceplate  335 , but in alternative embodiments one or more gaps between the enclosure  331  and the faceplate  335  may facilitate the passage of sound and/or light through the doorbell  330 . The enclosure  331  may comprise any suitable material, but in some embodiments the material of the enclosure  331  preferably permits infrared light to pass through from inside the doorbell  330  to the environment and vice versa. The doorbell  330  further includes a lens  332 . In some embodiments, the lens may comprise a Fresnel lens, which may be patterned to deflect incoming light into one or more infrared sensors located within the doorbell  330 . The doorbell  330  further includes a camera  334 , which captures video data when activated, as described below. 
       FIG. 15  is a rear view of the doorbell  330 , according to an aspect of the present embodiments. As illustrated, the enclosure  331  may extend from the front of the doorbell  330  around to the back thereof and may fit snugly around a lip of the back plate  339 . The back plate  339  may comprise any suitable material, including, without limitation, metals, such as brushed aluminum or stainless steel, metal alloys, or plastics. The back plate  339  protects the internal contents of the doorbell  330  and serves as an exterior rear surface of the doorbell  330 . The faceplate  335  may extend from the front of the doorbell  330  and at least partially wrap around the back plate  339 , thereby allowing a coupled connection between the faceplate  335  and the back plate  339 . The back plate  339  may have indentations in its structure to facilitate the coupling. 
     With further reference to  FIG. 15 , spring contacts  340  may provide power to the doorbell  330  when mated with other conductive contacts connected to a power source. The spring contacts  340  may comprise any suitable conductive material, including, without limitation, copper, and may be capable of deflecting when contacted by an inward force, for example the insertion of a mating element. The doorbell  330  further comprises a connector  360 , such as a micro-USB or other connector, whereby power and/or data may be supplied to and from the components within the doorbell  330 . A reset button  359  may be located on the back plate  339 , and may make contact with a button actuator (not shown) located within the doorbell  330  when the reset button  359  is pressed. When the reset button  359  is pressed, it may trigger one or more functions, as described below. 
       FIG. 16  is a right side cross-sectional view of the doorbell  330  without the mounting bracket  337 . In the illustrated embodiment, the lens  332  is substantially coplanar with the front surface  331 F of the enclosure  331 . In alternative embodiments, the lens  332  may be recessed within the enclosure  331  or may protrude outward from the enclosure  331 . The camera  334  is coupled to a camera printed circuit board (PCB)  347 , and a lens  334   a  of the camera  334  protrudes through an opening in the enclosure  331 . The camera lens  334   a  may be a lens capable of focusing light into the camera  334  so that clear images may be taken. 
     The camera PCB  347  may be secured within the doorbell with any suitable fasteners, such as screws, or interference connections, adhesives, etc. The camera PCB  347  comprises various components that enable the functionality of the camera  334  of the doorbell  330 , as described below. Infrared light-emitting components, such as infrared LED&#39;s  368 , are coupled to the camera PCB  347  and may be triggered to activate when a light sensor detects a low level of ambient light. When activated, the infrared LED&#39;s  368  may emit infrared light through the enclosure  331  and/or the camera  334  out into the ambient environment. The camera  334 , which may be configured to detect infrared light, may then capture the light emitted by the infrared LED&#39;s  368  as it reflects off objects within the camera&#39;s  334  field of view, so that the doorbell  330  can clearly capture images at night (may be referred to as “night vision”). 
     With continued reference to  FIG. 16 , the doorbell  330  further comprises a front PCB  346 , which in the illustrated embodiment resides in a lower portion of the doorbell  330  adjacent a battery  366 . The front PCB  346  may be secured within the doorbell  330  with any suitable fasteners, such as screws, or interference connections, adhesives, etc. The front PCB  346  comprises various components that enable the functionality of the audio and light components, as further described below. The battery  366  may provide power to the doorbell  330  components while receiving power from the spring contacts  340 , thereby engaging in a trickle-charge method of power consumption and supply. Alternatively, the doorbell  330  may draw power directly from the spring contacts  340  while relying on the battery  366  only when the spring contacts  340  are not providing the power necessary for all functions. Still further, the battery  366  may comprise the sole source of power for the doorbell  330 . In such embodiments, the spring contacts  340  may not be connected to a source of power. When the battery  366  is depleted of its charge, it may be recharged, such as by connecting a power source to the connector  360 . 
     With continued reference to  FIG. 16 , the doorbell  330  further comprises a power PCB  348 , which in the illustrated embodiment resides behind the camera PCB  347 . The power PCB  348  may be secured within the doorbell  330  with any suitable fasteners, such as screws, or interference connections, adhesives, etc. The power PCB  348  comprises various components that enable the functionality of the power and device-control components, as further described below. 
     With continued reference to  FIG. 16 , the doorbell  330  further comprises a communication module  364  coupled to the power PCB  348 . The communication module  364  facilitates communication with client devices in one or more remote locations, as further described below. The connector  360  may protrude outward from the power PCB  348  and extend through a hole in the back plate  339 . The doorbell  330  further comprises passive infrared (PIR) sensors  344 , which are secured on or within a PIR sensor holder  343 , and the assembly resides behind the lens  332 . In some embodiments, the doorbell  330  may comprise three PIR sensors  344 , as further described below, but in other embodiments any number of PIR sensors  344  may be provided. The PIR sensor holder  343  may be secured to the doorbell  330  with any suitable fasteners, such as screws, or interference connections, adhesives, etc. The PIR sensors  344  may be any type of sensor capable of detecting and communicating the presence of a heat source within their field of view. Further, alternative embodiments may comprise one or more motion sensors either in place of or in addition to the PIR sensors  344 . The motion sensors may be configured to detect motion using any methodology, such as a methodology that does not rely on detecting the presence of a heat source within a field of view. 
       FIG. 17  is an exploded view of the doorbell  330  and the mounting bracket  337  according to an aspect of the present embodiments. The mounting bracket  337  is configured to be mounted to a mounting surface (not shown) of a structure, such as a home or an office.  FIG. 17  shows the front side  337 F of the mounting bracket  337 . The mounting bracket  337  is configured to be mounted to the mounting surface such that the back side  337 B thereof faces the mounting surface. In certain embodiments, the mounting bracket  337  may be mounted to surfaces of various composition, including, without limitation, wood, concrete, stucco, brick, vinyl siding, aluminum siding, etc., with any suitable fasteners, such as screws, or interference connections, adhesives, etc. The doorbell  330  may be coupled to the mounting bracket  337  with any suitable fasteners, such as screws, or interference connections, adhesives, etc. 
     With continued reference to  FIG. 17 , the illustrated embodiment of the mounting bracket  337  includes the terminal screws  338 . The terminal screws  338  are configured to receive electrical wires adjacent the mounting surface of the structure upon which the mounting bracket  337  is mounted, so that the doorbell  330  may receive electrical power from the structure&#39;s electrical system. The terminal screws  338  are electrically connected to electrical contacts  377  of the mounting bracket. If power is supplied to the terminal screws  338 , then the electrical contacts  377  also receive power through the terminal screws  338 . The electrical contacts  377  may comprise any suitable conductive material, including, without limitation, copper, and may protrude slightly from the face of the mounting bracket  337  so that they may mate with the spring contacts  340  located on the back plate  339 . 
     With continued reference to  FIG. 17 , the mounting bracket  337  further comprises a bracket PCB  349 . The bracket PCB  349  is situated outside the doorbell  330 , and is therefore configured for various sensors that measure ambient conditions, such as an accelerometer  350 , a barometer  351 , a humidity sensor  352 , and a temperature sensor  353  ( FIG. 18 ). The functions of these components are discussed in more detail below. The bracket PCB  349  may be secured to the mounting bracket  337  with any suitable fasteners, such as screws, or interference connections, adhesives, etc. 
     With continued reference to  FIG. 17 , the faceplate  335  may extend from the bottom of the doorbell  330  up to just below the camera  334 , and connect to the back plate  339  as described above. The lens  332  may extend and curl partially around the side of the doorbell  330 . The enclosure  331  may extend and curl around the side and top of the doorbell  330 , and may be coupled to the back plate  339  as described above. The camera  334  may protrude slightly through the enclosure  331 , thereby giving it a wider field of view. The mounting bracket  337  may couple with the back plate  339  such that they contact each other at various points in a common plane of contact, thereby creating an assembly including the doorbell  330  and the mounting bracket  337 . The couplings described in this paragraph, and elsewhere, may be secured by, for example and without limitation, screws, interference fittings, adhesives, or other fasteners. Interference fittings may refer to a type of connection where a material relies on pressure and/or gravity coupled with the material&#39;s physical strength to support a connection to a different element. 
       FIG. 18  is a top view and  FIG. 19  is a front view of a passive infrared sensor assembly  179  including the lens  132 , the passive infrared sensor holder  143 , the passive infrared sensors  144 , and a flexible power circuit  145 . The passive infrared sensor holder  143  is configured to mount the passive infrared sensors  144  facing out through the lens  132  at varying angles, thereby allowing the passive infrared sensor  144  field of view to be expanded to 180° or more and also broken up into various zones, as further described below. The passive infrared sensor holder  143  may include one or more faces  178 , including a center face  178 C and two side faces  178 S to either side of the center face  178 C. With reference to  FIG. 19 , each of the faces  178  defines an opening  181  within or on which the passive infrared sensors  144  may be mounted. In alternative embodiments, the faces  178  may not include openings  181 , but may instead comprise solid flat faces upon which the passive infrared sensors  144  may be mounted. Generally, the faces  178  may be any physical structure capable of housing and/or securing the passive infrared sensors  144  in place. 
     With reference to  FIG. 18 , the passive infrared sensor holder  143  may be secured to the rear face of the lens  132 . The flexible power circuit  145  may be any material or component capable of delivering power and/or data to and from the passive infrared sensors  144 , and may be contoured to conform to the non-linear shape of the passive infrared sensor holder  143 . The flexible power circuit  145  may connect to, draw power from, and/or transmit data to and from, the power printed circuit board  148 . 
       FIG. 20  is a top view of the passive infrared sensor assembly  179  illustrating the fields of view of the passive infrared sensors  144 . In the illustrated embodiment, the side faces  178 S of the passive infrared sensor holder  143  are angled at 55° facing outward from the center face  178 C, and each passive infrared sensor  144  has a field of view of 110°. However, these angles may be increased or decreased as desired. Zone  1  is the area that is visible only to a first one of the passive infrared sensors  144 - 1 . Zone  2  is the area that is visible only to the first passive infrared sensor  144 - 1  and a second one of the passive infrared sensors  144 - 2 . Zone  3  is the area that is visible only to the second passive infrared sensor  144 - 2 . Zone  4  is the area that is visible only to the second passive infrared sensor  144 - 2  and a third one of the passive infrared sensors  144 - 3 . Zone  5  is the area that is visible only to the third passive infrared sensor  144 - 3 . In some embodiments, the doorbell  130  may be capable of determining the direction that an object is moving based upon which zones are triggered in a time sequence. 
       FIG. 21  is a functional block diagram of the components within or in communication with the doorbell  330 , according to an aspect of the present embodiments. As described above, the bracket PCB  349  may comprise an accelerometer  350 , a barometer  351 , a humidity sensor  352 , and a temperature sensor  353 . The accelerometer  350  may be one or more sensors capable of sensing motion and/or acceleration. The barometer  351  may be one or more sensors capable of determining the atmospheric pressure of the surrounding environment in which the bracket PCB  349  may be located. The humidity sensor  352  may be one or more sensors capable of determining the amount of moisture present in the atmospheric environment in which the bracket PCB  349  may be located. The temperature sensor  353  may be one or more sensors capable of determining the temperature of the ambient environment in which the bracket PCB  349  may be located. As described above, the bracket PCB  349  may be located outside the housing of the doorbell  330  so as to reduce interference from heat, pressure, moisture, and/or other stimuli generated by the internal components of the doorbell  330 . 
     With further reference to  FIG. 21 , the bracket PCB  349  may further comprise terminal screw inserts  354 , which may be configured to receive the terminal screws  338  and transmit power to the electrical contacts  377  on the mounting bracket  337  ( FIG. 17 ). The bracket PCB  349  may be electrically and/or mechanically coupled to the power PCB  348  through the terminal screws  338 , the terminal screw inserts  354 , the spring contacts  340 , and the electrical contacts  377 . The terminal screws  338  may receive electrical wires located at the surface to which the doorbell  330  is mounted, such as the wall of a building, so that the doorbell can receive electrical power from the building&#39;s electrical system. Upon the terminal screws  338  being secured within the terminal screw inserts  354 , power may be transferred to the bracket PCB  349 , and to all of the components associated therewith, including the electrical contacts  377 . The electrical contacts  377  may transfer electrical power to the power PCB  348  by mating with the spring contacts  340 . 
     With further reference to  FIG. 21 , the front PCB  346  may comprise a light sensor  355 , one or more light-emitting components, such as LED&#39;s  356 , one or more speakers  357 , and a microphone  358 . The light sensor  355  may be one or more sensors capable of detecting the level of ambient light of the surrounding environment in which the doorbell  330  may be located. LED&#39;s  356  may be one or more light-emitting diodes capable of producing visible light when supplied with power. The speakers  357  may be any electromechanical device capable of producing sound in response to an electrical signal input. The microphone  358  may be an acoustic-to-electric transducer or sensor capable of converting sound waves into an electrical signal. When activated, the LED&#39;s  356  may illuminate the light pipe  336  ( FIG. 14 ). The front PCB  346  and all components thereof may be electrically coupled to the power PCB  348 , thereby allowing data and/or power to be transferred to and from the power PCB  348  and the front PCB  346 . 
     The speakers  357  and the microphone  358  may be coupled to the camera processor  370  through an audio CODEC  361 . For example, the transfer of digital audio from the user&#39;s client device  114  and the speakers  357  and the microphone  358  may be compressed and decompressed using the audio CODEC  361 , coupled to the camera processor  370 . Once compressed by audio CODEC  361 , digital audio data may be sent through the communication module  364  to the network  112 , routed by one or more servers  118 , and delivered to the user&#39;s client device  114 . When the user speaks, after being transferred through the network  112 , digital audio data is decompressed by audio CODEC  361  and emitted to the visitor via the speakers  357 . 
     With further reference to  FIG. 21 , the power PCB  348  may comprise a power management module  362 , a microcontroller  363  (may also be referred to as “processor,” “CPU,” or “controller”), the communication module  364 , and power PCB non-volatile memory  365 . In certain embodiments, the power management module  362  may comprise an integrated circuit capable of arbitrating between multiple voltage rails, thereby selecting the source of power for the doorbell  330 . The battery  366 , the spring contacts  340 , and/or the connector  360  may each provide power to the power management module  362 . The power management module  362  may have separate power rails dedicated to the battery  366 , the spring contacts  340 , and the connector  360 . In one aspect of the present disclosure, the power management module  362  may continuously draw power from the battery  366  to power the doorbell  330 , while at the same time routing power from the spring contacts  340  and/or the connector  360  to the battery  366 , thereby allowing the battery  366  to maintain a substantially constant level of charge. Alternatively, the power management module  362  may continuously draw power from the spring contacts  340  and/or the connector  360  to power the doorbell  330 , while only drawing from the battery  366  when the power from the spring contacts  340  and/or the connector  360  is low or insufficient. Still further, the battery  366  may comprise the sole source of power for the doorbell  330 . In such embodiments, the spring contacts  340  may not be connected to a source of power. When the battery  366  is depleted of its charge, it may be recharged, such as by connecting a power source to the connector  360 . The power management module  362  may also serve as a conduit for data between the connector  360  and the microcontroller  363 . 
     With further reference to  FIG. 21 , in certain embodiments the microcontroller  363  may comprise an integrated circuit including a processor core, memory, and programmable input/output peripherals. The microcontroller  363  may receive input signals, such as data and/or power, from the PIR sensors  344 , the bracket PCB  349 , the power management module  362 , the light sensor  355 , the microphone  358 , and/or the communication module  364 , and may perform various functions as further described below. When the microcontroller  363  is triggered by the PIR sensors  344 , the microcontroller  363  may be triggered to perform one or more functions. When the light sensor  355  detects a low level of ambient light, the light sensor  355  may trigger the microcontroller  363  to enable night vision, as further described below. The microcontroller  363  may also act as a conduit for data communicated between various components and the communication module  364 . 
     With further reference to  FIG. 21 , the communication module  364  may comprise an integrated circuit including a processor core, memory, and programmable input/output peripherals. The communication module  364  may also be configured to transmit data wirelessly to a remote network device, and may include one or more transceivers (not shown). The wireless communication may comprise one or more wireless networks, such as, without limitation, Wi-Fi, cellular, Bluetooth, and/or satellite networks. The communication module  364  may receive inputs, such as power and/or data, from the camera PCB  347 , the microcontroller  363 , the button  333 , the reset button  359 , and/or the power PCB non-volatile memory  365 . When the button  333  is pressed, the communication module  364  may be triggered to perform one or more functions. When the reset button  359  is pressed, the communication module  364  may be triggered to erase any data stored at the power PCB non-volatile memory  365  and/or at the camera PCB memory  369 . The communication module  364  may also act as a conduit for data communicated between various components and the microcontroller  363 . The power PCB non-volatile memory  365  may comprise flash memory configured to store and/or transmit data. For example, in certain embodiments the power PCB non-volatile memory  365  may comprise serial peripheral interface (SPI) flash memory. 
     With further reference to  FIG. 21 , the camera PCB  347  may comprise components that facilitate the operation of the camera  334 . For example, an imager  371  may comprise a video recording sensor and/or a camera chip. In one aspect of the present disclosure, the imager  371  may comprise a complementary metal-oxide semiconductor (CMOS) array, and may be capable of recording high definition (e.g., 1080p or better) video files. A camera processor  370  may comprise an encoding and compression chip. In some embodiments, the camera processor  370  may comprise a bridge processor. The camera processor  370  may process video recorded by the imager  371  and audio recorded by the microphone  358 , and may transform this data into a form suitable for wireless transfer by the communication module  364  to a network. The camera PCB memory  369  may comprise volatile memory that may be used when data is being buffered or encoded by the camera processor  370 . For example, in certain embodiments the camera PCB memory  369  may comprise synchronous dynamic random access memory (SD RAM). IR LED&#39;s  368  may comprise light-emitting diodes capable of radiating infrared light. IR cut filter  367  may comprise a system that, when triggered, configures the imager  371  to see primarily infrared light as opposed to visible light. When the light sensor  355  detects a low level of ambient light (which may comprise a level that impedes the performance of the imager  371  in the visible spectrum), the IR LED&#39;s  368  may shine infrared light through the doorbell  330  enclosure out to the environment, and the IR cut filter  367  may enable the imager  371  to see this infrared light as it is reflected or refracted off of objects within the field of view of the doorbell. This process may provide the doorbell  330  with the night vision function mentioned above. 
     Some of the present embodiments comprise computer vision for one or more aspects, such as object recognition. Computer vision includes methods for acquiring, processing, analyzing, and understanding images and, in general, high-dimensional data from the real world in order to produce numerical or symbolic information, e.g. in the form of decisions. Computer vision seeks to duplicate the abilities of human vision by electronically perceiving and understanding an image. Understanding in this context means the transformation of visual images (the input of the retina) into descriptions of the world that can interface with other thought processes and elicit appropriate action. This image understanding can be seen as the disentangling of symbolic information from image data using models constructed with the aid of geometry, physics, statistics, and learning theory. Computer vision has also been described as the enterprise of automating and integrating a wide range of processes and representations for vision perception. As a scientific discipline, computer vision is concerned with the theory behind artificial systems that extract information from images. The image data can take many forms, such as video sequences, views from multiple cameras, or multi-dimensional data from a scanner. As a technological discipline, computer vision seeks to apply its theories and models for the construction of computer vision systems. 
     One aspect of computer vision comprises determining whether or not the image data contains some specific object, feature, or activity. Different varieties of computer vision recognition include: Object Recognition (also called object classification)—One or several pre-specified or learned objects or object classes can be recognized, usually together with their 2D positions in the image or 3D poses in the scene. Identification—An individual instance of an object is recognized. Examples include identification of a specific person&#39;s face or fingerprint, identification of handwritten digits, or identification of a specific vehicle. Detection—The image data are scanned for a specific condition. Examples include detection of possible abnormal cells or tissues in medical images or detection of a vehicle in an automatic road toll system. Detection based on relatively simple and fast computations is sometimes used for finding smaller regions of interesting image data that can be further analyzed by more computationally demanding techniques to produce a correct interpretation. 
     Several specialized tasks based on computer vision recognition exist, such as: Optical Character Recognition (OCR)—Identifying characters in images of printed or handwritten text, usually with a view to encoding the text in a format more amenable to editing or indexing (e.g. ASCII). 2D Code Reading—Reading of 2D codes such as data matrix and QR codes. Facial Recognition. Shape Recognition Technology (SRT)—Differentiating human beings (e.g. head and shoulder patterns) from objects. 
     Typical functions and components (e.g. hardware) found in many computer vision systems are described in the following paragraphs. The present embodiments may include at least some of these aspects. For example, with reference to  FIG. 3 , embodiments of the present A/V recording and communication device  130  may include a computer vision module  163 . The computer vision module  163  may include any of the components (e.g. hardware) and/or functionality described herein with respect to computer vision, including, without limitation, one or more cameras, sensors, and/or processors. In some embodiments, the microphone  150 , the camera  154 , and/or the imaging processor  240  may be components of the computer vision module  163 . 
     Image acquisition—A digital image is produced by one or several image sensors, which, besides various types of light-sensitive cameras, may include range sensors, tomography devices, radar, ultra-sonic cameras, etc. Depending on the type of sensor, the resulting image data may be a 2D image, a 3D volume, or an image sequence. The pixel values may correspond to light intensity in one or several spectral bands (gray images or color images), but can also be related to various physical measures, such as depth, absorption or reflectance of sonic or electromagnetic waves, or nuclear magnetic resonance. 
     Pre-processing—Before a computer vision method can be applied to image data in order to extract some specific piece of information, it is usually beneficial to process the data in order to assure that it satisfies certain assumptions implied by the method. Examples of pre-processing include, but are not limited to re-sampling in order to assure that the image coordinate system is correct, noise reduction in order to assure that sensor noise does not introduce false information, contrast enhancement to assure that relevant information can be detected, and scale space representation to enhance image structures at locally appropriate scales. 
     Feature extraction—Image features at various levels of complexity are extracted from the image data. Typical examples of such features are: Lines, edges, and ridges; Localized interest points such as corners, blobs, or points; More complex features may be related to texture, shape, or motion. 
     Detection/segmentation—At some point in the processing a decision may be made about which image points or regions of the image are relevant for further processing. Examples are: Selection of a specific set of interest points; Segmentation of one or multiple image regions that contain a specific object of interest; Segmentation of the image into nested scene architecture comprising foreground, object groups, single objects, or salient object parts (also referred to as spatial-taxon scene hierarchy). 
     High-level processing—At this step, the input may be a small set of data, for example a set of points or an image region that is assumed to contain a specific object. The remaining processing may comprise, for example: Verification that the data satisfy model-based and application-specific assumptions; Estimation of application-specific parameters, such as object pose or object size; Image recognition—classifying a detected object into different categories; Image registration—comparing and combining two different views of the same object. 
     Decision making—Making the final decision required for the application, for example match/no-match in recognition applications. 
     One or more of the present embodiments may include a vision processing unit (not shown separately, but may be a component of the computer vision module  163 ). A vision processing unit is an emerging class of microprocessor; it is a specific type of AI (artificial intelligence) accelerator designed to accelerate machine vision tasks. Vision processing units are distinct from video processing units (which are specialized for video encoding and decoding) in their suitability for running machine vision algorithms such as convolutional neural networks, SIFT, etc. Vision processing units may include direct interfaces to take data from cameras (bypassing any off-chip buffers), and may have a greater emphasis on on-chip dataflow between many parallel execution units with scratchpad memory, like a many core DSP (digital signal processor). But, like video processing units, vision processing units may have a focus on low precision fixed point arithmetic for image processing. 
     Some of the present embodiments may use facial recognition hardware and/or software, as a part of the computer vision system. Various types of facial recognition exist, some or all of which may be used in the present embodiments. 
     Some face recognition algorithms identify facial features by extracting landmarks, or features, from an image of the subject&#39;s face. For example, an algorithm may analyze the relative position, size, and/or shape of the eyes, nose, cheekbones, and jaw. These features are then used to search for other images with matching features. Other algorithms normalize a gallery of face images and then compress the face data, only saving the data in the image that is useful for face recognition. A probe image is then compared with the face data. One of the earliest successful systems is based on template matching techniques applied to a set of salient facial features, providing a sort of compressed face representation. 
     Recognition algorithms can be divided into two main approaches, geometric, which looks at distinguishing features, or photometric, which is a statistical approach that distills an image into values and compares the values with templates to eliminate variances. 
     Popular recognition algorithms include principal component analysis using eigenfaces, linear discriminant analysis, elastic bunch graph matching using the Fisherface algorithm, the hidden Markov model, the multilinear subspace learning using tensor representation, and the neuronal motivated dynamic link matching. 
     Further, a newly emerging trend, claimed to achieve improved accuracy, is three-dimensional face recognition. This technique uses 3D sensors to capture information about the shape of a face. This information is then used to identify distinctive features on the surface of a face, such as the contour of the eye sockets, nose, and chin. 
     One advantage of 3D face recognition is that it is not affected by changes in lighting like other techniques. It can also identify a face from a range of viewing angles, including a profile view. Three-dimensional data points from a face vastly improve the precision of face recognition. 3D research is enhanced by the development of sophisticated sensors that do a better job of capturing 3D face imagery. The sensors work by projecting structured light onto the face. Up to a dozen or more of these image sensors can be placed on the same CMOS chip—each sensor captures a different part of the spectrum. 
     Another variation is to capture a 3D picture by using three tracking cameras that point at different angles; one camera pointing at the front of the subject, a second one to the side, and a third one at an angle. All these cameras work together to track a subject&#39;s face in real time and be able to face detect and recognize. 
     Another emerging trend uses the visual details of the skin, as captured in standard digital or scanned images. This technique, called skin texture analysis, turns the unique lines, patterns, and spots apparent in a person&#39;s skin into a mathematical space. 
     Another form of taking input data for face recognition is by using thermal cameras, which may only detect the shape of the head and ignore the subject accessories such as glasses, hats, or make up. 
     Further examples of automatic identification and data capture (AIDC) and/or computer vision that can be used in the present embodiments to verify the identity and/or authorization of a person include, without limitation, biometrics. Biometrics refers to metrics related to human characteristics. Biometrics authentication (or realistic authentication) is used in various forms of identification and access control. Biometric identifiers are the distinctive, measurable characteristics used to label and describe individuals. Biometric identifiers can be physiological characteristics and/or behavioral characteristics. Physiological characteristics may be related to the shape of the body. Examples include, but are not limited to, fingerprints, palm veins, facial recognition, three-dimensional facial recognition, skin texture analysis, DNA, palm prints, hand geometry, iris recognition, retina recognition, and odor/scent recognition. Behavioral characteristics may be related to the pattern of behavior of a person, including, but not limited to, typing rhythm, gait, and voice recognition. 
     The present embodiments may use any one, or any combination of more than one, of the foregoing biometrics to identify and/or authenticate a person who is either suspicious or who is authorized to take certain actions with respect to a property or expensive item of collateral. For example, the computer vision module  163 , and/or the camera  154  and/or the processor  160  may receive information about the person using any one, or any combination of more than one, of the foregoing biometrics. 
     One aspect of the present embodiments includes the realization that in current audio/video (A/V) recording and communication devices (e.g., doorbells) other than the present embodiments, users of said devices would benefit from as great a flexibility as possible regarding their options for setting notifications and alert tones. Further, users would benefit from the capability to set different alert tones, and have their A/V recording and communication devices assume different operational modes, and thus perform different tasks, or provide different alerts, depending upon whether the user is present or absent from the home (or other location where the A/V recording and communication device is installed). Still further, users would benefit from the capability to set different operational modes when secondary users, such as a spouse or child, are home alone, and to receive different notifications and/or alert tones when their loved ones are home alone. 
     With reference to  FIGS. 22-24 , to address the foregoing shortcomings of A/V recording and communication devices, such devices may be designed and/or programmed to execute the processes and/or functions described below, either alone, in conjunction with one or more wireless client devices, such as one or more smartphones, and/or in conjunction with one or more other linked A/V recording and communication devices, and/or in conjunction with one or more backend devices including, but not limited to, servers and API&#39;s, with communication via suitable channels, including long-range wireless channels (e.g., cellular communication channels), mid-range wireless channels (e.g., Wi-Fi), short-range wireless channels (e.g., Bluetooth), wired channels (e.g., Ethernet), etc. 
     In a first aspect, a method according to the present embodiments includes the ability to set one or more different operational modes for the A/V recording and communication devices  130 , depending upon the location of the registered user. For example, with reference to  FIG. 22 , the method may comprise setting a first operational mode at block B 300  for the A/V recording and communication device  130 . The A/V recording and communication device  130  then determines, at block B 302 , whether a registered user of the A/V recording and communication device is within a predetermined proximity of the A/V recording and communication device. Upon determining that the registered user of the A/V recording and communication device is not within the predetermined proximity of the A/V recording and communication device  130 , the device sets a second operational mode for the A/V recording and communication device at block B 304 . In some embodiments, the first operational mode is a normal, unarmed, or at-home mode, while the second operational mode is an armed or away-from-home mode. In certain embodiments below, the second operational mode is a heightened security mode. 
     The present disclosure is not limited to the setting of only two operational modes. The present disclosure contemplates that a plurality of different operational modes, different alert tones, and/or automated actions, may be programmed and/or set, depending upon the needs and desires of the registered user. 
     In some embodiments, the A/V recording and communication device  130 ,  330  includes a camera  154 ,  334  and/or a motion sensor  344 , and a speaker  152 ,  357 . One method contemplates using the camera  154 ,  334  and/or the motion sensor  344  to detect motion within a field of view of the A/V recording and communication device  130 ,  330  to detect the presence of a person, whether it is an expected visitor, an unexpected visitor, a solicitor, a neighbor, a burglar, etc. The A/V recording and communication device  130 ,  330  may then either transition from a current operational mode to another operational mode, or if a certain operational mode has been set, take certain actions that are different than actions that would be taken in a different operational mode. For example, upon detection of motion within the field of view of the A/V recording and communication device  130 ,  330 , the A/V recording and communication device  130 ,  330  may automatically play an audio alert from the speaker  152 ,  357  that can be heard by the person in the field of view of the A/V recording and communication device  130 ,  330 . This audio alert may take any form desired, ranging from a siren or bell, to a recorded voice politely asking the person to state their business, to a warning that police have been contacted and are en route. In an “at-home” operational mode, when the registered user is present and is expecting a visitor, the audio alert may be a polite greeting. However, in a second “away” or “nighttime” operational mode, when the registered user is not present, not expecting a visitor, and/or it is nighttime, the audio alert may be more aggressive or in the nature of a warning not to approach the property. It is contemplated that such an audio alert, which is made so that the visitor can hear the audio alert, will reduce incidences of burglary and/or unauthorized visitors. This embodiment may further include electronic components and software to enable multiple A/V recording and communication devices  130 ,  330  to be operatively linked, such as via a backend API, such as, for example, when a homeowner installs a separate A/V recording and communication device  130 ,  330  at each entry point to a home. This operative linkage then allows an audio alert to be played on all linked A/V recording and communication devices  130 ,  330  when motion is detected on any one of the A/V recording and communication devices  130 ,  330 . This functionality increases the likelihood that unwanted intruders will hear the warning, and also may increase the likelihood that unwanted intruders will flee upon hearing the warning. 
     The determination of whether the registered user is within a particular proximity to the A/V recording and communication device  130 ,  330  can be accomplished in a number of different ways, and the following description is not intended to be limiting. In one embodiment, the proximity of the registered user may be determined by registering a wireless client device  800  associated with the registered user to the A/V recording and communication device  130 ,  330 . This registration is often accomplished at the time that the A/V recording and communication device  130 ,  330  is first set-up and installed, but it could be performed at any time. Then, the A/V recording and communication device  130 ,  330  may determine whether the registered wireless client device  800  is within the predetermined proximity of the A/V recording and communication device  130 ,  330 . The wireless client device  800  may be, for example, a smartphone, a wearable device, a tablet, a phablet, or any other known computing and communication device from which location information can be determined, either directly or indirectly. 
     For example, in certain embodiments, the wireless client device  800 , such as a smartphone, may have built-in GPS (Global Positioning System) components for generating location information and determining the location of the wireless client device  800 . This GPS location information can be transmitted from the wireless client device, through an application program (“app”), directly or indirectly to the A/V recording and communication device  130 ,  330 , or to a backend API. Similarly, location information can be determined for the A/V recording and communication device  130 ,  330 . The location information for the A/V recording and communication device  130 ,  330  can be generated based on a GPS location system in the A/V recording and communication device itself, or may be based on the location where the device has been installed, as provided by the registered user to a backend API during a set-up process of the A/V recording and communication device  130 ,  330 . The location information of the wireless client device  800  and the location information of the A/V recording and communication device  130 ,  330  can then be compared, either substantially continuously, or at regular intervals, such as every minute, every two minutes, every five minutes, or intervals of any other length, or at irregular intervals. This comparison evaluates whether the registered wireless client device  800  is within some predetermined proximity to the A/V recording and communication device  130 ,  330 . The predetermined proximity may be set by a user, or set as a default upon set-up. The predetermined proximity may be a distance that is such that, when a registered user&#39;s wireless client device  800  is within or close to the property being protected by the A/V recording and communication device  130 ,  330 , the registered user can be understood to be “at home.” As such, this predetermined proximity value may vary depending upon the type of property (e.g., a city apartment versus a multi-acre rural home), the neighborhood, and/or the user&#39;s preferences. That said, this predetermined proximity value may be, for example, 50 feet, 100 feet, 200 feet, 400 feet, etc. 
     Other embodiments may use signals sent and received directly between the wireless client device  800  to the A/V recording and communication device  130 ,  330  to determine proximity. In one embodiment, the A/V recording and communication device  130 ,  330  may have a receiver for receiving Bluetooth signals, including but not limited to one or more Bluetooth Low Energy beacons. The A/V recording and communication device  130 ,  330  in such embodiments can be programmed to recognize that when a Bluetooth signal is received from a registered wireless client device  800 , including a Bluetooth signal that is stronger than a particular threshold value, that the registered wireless client device is within range and therefore within a predetermined proximity to the A/V recording and communication device  130 ,  330 . Alternatively, the A/V recording and communication device  130 ,  330  can be configured to transmit Bluetooth signals, including but not limited to Bluetooth Low Energy beacons, and upon receipt by a registered wireless client device  800 , and a recognition that the received Bluetooth signal is stronger than a particular threshold value, an app executing on the registered wireless client device may report to a backend API that the registered wireless client device  800  is within the predetermined proximity to the A/V recording and communication device  130 ,  330 . Similarly, in other embodiments, proximity can be recognized when the A/V recording and communication device  130 ,  330  and the registered wireless client  800  are in communication with the same 802.11 Wi-Fi network (or other wireless network) or the same 802.3 Ethernet network (or other wired network), if the wireless client device  800  is plugged in. 
     Other embodiments may use the camera  154 ,  334 , in combination with computer vision, facial recognition, and/or other biometrics, to determine whether the registered user of the A/V recording and communication device  130 ,  330  is within the predetermined proximity of the A/V recording and communication device  130 ,  330 . Such embodiments may allow uploading of first image data, such as a digital photograph of the registered user, to a database that is accessible to the A/V recording and communication device  130 ,  330 . The user may then provide other identifying information, such as additional images, biometric information, and/or the location of the installed A/V recording and communication device  130 ,  330 . The A/V recording and communication device  130 ,  330  may be programmed to receive second image data, for example of a person within a field of view of the camera  154 ,  334 , such as an image of the person&#39;s face as they approach the A/V recording and communication device  130 ,  330 , and determine, by comparing the first image data and the second image data, whether the person is the registered user. In some embodiments, the first image data comprises first biometric data and the second image data comprises second biometric data. 
     In one embodiment, when the A/V recording and communication device  130 ,  330  is in the heightened security mode, the camera  154 ,  334  continuously records video images and, upon detecting any motion in the field of view of the camera  154 ,  334  or the motion sensor  344 , sends an alert to the wireless client device  800 . Upon receiving the alert, an application executing in the wireless client device  800  may play an audible tone and/or enable the near-real time viewing of the recorded video images. In another embodiment, the audible tone may be uniquely associated with a severity of the alert. For example, particular pitches, patterns, volumes, and/or ringtones may be selected by the registered user, or set as defaults, to indicate that the A/V recording and communication device  130 ,  330  has entered a second operational mode, has detected movement (either with the camera  154 ,  334  or with the motion sensor  344 ), has had an actuation of the doorbell button, or other events such as those described herein. 
     With reference to  FIG. 23 , in another aspect a method is provided for an audio/video (A/V) recording and communication device  130 ,  330  to set different operational modes and take different actions based upon the presence or absence of both a registered user and one or more secondary users of the A/V recording and communication device  130 ,  330 . In one embodiment, the method comprises setting a first operational mode for the A/V recording and communication device at block B 400 , determining whether a primary registered user of the A/V recording and communication device is within a predetermined proximity of the A/V recording and communication device at block B 402 , determining whether at least one secondary registered user of the A/V recording and communication device is within the predetermined proximity of the A/V recording and communication device at block B 404 , and upon determining that the primary registered user is outside of the predetermined proximity and that the at least one secondary registered user is inside the predetermined proximity, setting a second operational mode for the A/V recording and communication device at block B 406 . Such a method may be beneficial to a registered user who desires to have his A/V recording and communication device  130 ,  330  be in a heightened security mode when he or she is away from home, but a secondary registered user, such as a spouse or child, is at home. 
     Approaches and techniques for determining the presence and proximity of the registered user to the A/V recording and communication device  130 ,  330 , and setting different operational modes and actions, are discussed above. Similar approaches and techniques may be employed to determine the presence and/or proximity of one or more secondary users. The determination regarding the presence, absence, or proximity of the primary registered user, as well as the determination regarding the presence, absence, or proximity of the secondary registered user, may then be used in a variety of combinations to set various operational modes and actions. 
     In a still further embodiment, a second wireless client device  800  may include an RFID chip. Such an embodiment may be useful where the secondary user is a minor child who does not otherwise possess a smartphone, tablet, or other wireless device, but the child&#39;s parent, who is the primary registered user, desires to be able to set different operational modes depending upon the child&#39;s proximity to the A/V recording and communication device  130 ,  330 . As such, an RFID chip may be associated with the secondary user. This may be accomplished in any number of ways, such as by attaching the RFID chip to a wearable device, to the child&#39;s favorite toy (e.g., the child&#39;s security blanket or favorite stuffed animal), or to a regularly worn article of the child&#39;s clothing (e.g., the child&#39;s favorite sneakers or a winter coat). In some embodiments, more than one RFID chip could be used for this approach. 
     In another embodiment, the method further comprises generating and transmitting an alert to a security monitoring company if certain actions occur while the A/V recording and communication device  130 ,  330  is in the second operational mode. For example, if, while the A/V recording and communication device  130 ,  330  is in the heightened second operational mode and the doorbell button is depressed, the A/V recording and communication device  130 ,  330  and all other A/V recording and communication devices  130 ,  330  installed on the same property may immediately begin recording video, and may further transmit an alert to the registered user. This alert may be generated and transmitted by the A/V recording and communication device  130 ,  330 , by the wireless client device  800 , in combination with an app, or by the backend API. 
     In another embodiment, different operational modes may be set and/or different actions may be taken based on the actions of persons who may be, or who may appear to be, suspicious. For example, a heightened security operational mode may be set if the same visitor returns, or loiters, in the field of view of the camera  154 ,  334 , particularly while the registered user is outside of a predetermined proximity of the A/V recording and communication device  130 ,  330 , and/or while a secondary user is within a predetermined proximity of the A/V recording and communication device  130 ,  330 . It should be noted that the predetermined proximity associated with the registered user can be different than the predetermined proximity associated with each of the one or more secondary users. Such a method may be desired and beneficial for notifying the registered user when a particular visitor is repeatedly visiting the home while they are not present. While not limiting, such scenarios could include repeat visits of an undesirable friend of a minor child, a paramour of a faithless spouse, or an intimidating door-to-door solicitor determined to take advantage of an elderly parent living at the home. Further, the present disclosure may be combined with and hereby incorporates by reference, as if fully set forth herein, the disclosure of previously filed U.S. Provisional Patent Application Ser. No. 62/464,342, entitled IDENTIFICATION OF SUSPICIOUS PERSONS USING AUDIO/VIDEO RECORDING AND COMMUNICATION DEVICES. 
       FIG. 24  is a sequence diagram illustrating communication signals sent and received among various devices according to various aspects of the present disclosure. As described above, a primary registered user may set an operational mode for the A/V recording and communication device  130 ,  330  using an application executing on the primary registered user&#39;s client device  800 . In some embodiments, this process may include the primary registered user&#39;s client device  800  sending an operational mode transition signal  420  to one or more backend network devices, such as one or more servers  118  and/or one or more APIs  120  ( FIG. 1 ). In response to receiving the operational mode transition signal  420 , the network device(s)  118 ,  120  may similarly send an operational mode transition signal  422  to the A/V recording and communication device  130 ,  330 . In alternative embodiments, the primary registered user&#39;s client device  800  may send the operational mode transition signal  420  directly to the A/V recording and communication device  130 ,  330  using a short-range communication protocol, such as Bluetooth or Bluetooth LE, rather than sending the signal through the backend. 
     In some embodiments, the primary registered user may set the operational mode of the A/V recording and communication device  130 ,  330  manually. For example, the primary registered user, upon arriving home, may manually change the operational mode of the A/V recording and communication device  130 ,  330  from the away mode to the at-home mode. Conversely, the primary registered user, as he or she is leaving home, may manually change the operational mode of the A/V recording and communication device  130 ,  330  from the at-home mode to the away mode. In other embodiments, the operational mode of the A/V recording and communication device  130 ,  330  may be changed automatically, such as according to an established schedule. For example, the primary registered user may set an operational mode transition schedule for the A/V recording and communication device  130 ,  330 , such as scheduling the A/V recording and communication device  130 ,  330  to be in away mode every Monday through Friday between 3:00 PM and 7:00 PM, and in at-home mode at all other times, unless manually switched to away mode. If the primary registered user sets an operational mode transition schedule for the A/V recording and communication device  130 ,  330 , then in such embodiments the operational mode transition signal  420  from the primary registered user&#39;s client device  800  to the backend network device(s)  118 ,  120  would not be sent every time the A/V recording and communication device  130 ,  330  transitions from one operational mode to another. Rather, the backend network device(s)  118 ,  120  would send the operational mode transition signal  422  to the A/V recording and communication device  130 ,  330  each time an operational mode transition was scheduled, according to the schedule set by the primary registered user. In alternative embodiments, the operational mode transition schedule could be managed locally by the A/V recording and communication device  130 ,  330 , such that the backend network device(s)  118 ,  120  would not need to send the operational mode transition signal  422  to the A/V recording and communication device  130 ,  330  each time an operational mode transition was scheduled. 
     In still further embodiments, the A/V recording and communication device  130 ,  330  may set an operational mode based on observed conditions, rather than in response from an operational mode transition signal from either the backend network device(s)  118 ,  120  or the primary registered user&#39;s client device  800 . Examples of observed conditions that might trigger an operational mode transition are discussed above, such as detecting that the primary registered user is home or not home (e.g., the primary registered user is within a predetermined proximity of the A/V recording and communication device  130 ,  330  or not within the predetermined proximity), and/or detecting that one or more secondary users are home or not home (e.g., the secondary user(s) is/are within a predetermined proximity of the A/V recording and communication device  130 ,  330  or not within the predetermined proximity). 
     With further reference to  FIG. 24 , the A/V recording and communication device  130 ,  330  may send a primary registered user proximity determination signal  424  to the backend network device(s)  118 ,  120 . In response to receiving the primary registered user proximity determination signal  424 , the network device(s)  118 ,  120  may similarly send a primary registered user proximity determination signal  426  to the primary registered user&#39;s client device  800 . In alternative embodiments, the A/V recording and communication device  130 ,  330  may send the primary registered user proximity determination signal  424  directly to the primary registered user&#39;s client device  800  using a short-range communication protocol, such as Bluetooth or Bluetooth LE, rather than sending the signal through the backend. 
     In response to receiving the primary registered user proximity determination signal  426 , the primary registered user&#39;s client device  800  may send a primary registered user proximity response signal  428  to the backend network device(s)  118 ,  120 . In response to receiving the primary registered user proximity response signal  428 , the network device(s)  118 ,  120  may similarly send a primary registered user proximity response signal  430  to the A/V recording and communication device  130 ,  330 . In alternative embodiments, such as those in which the primary registered user&#39;s client device  800  receives the primary registered user proximity determination signal  424  directly from the A/V recording and communication device  130 ,  330 , the primary registered user&#39;s client device  800  may send the primary registered user proximity response signal  428  directly to the A/V recording and communication device  130 ,  330  using a short-range communication protocol, such as Bluetooth or Bluetooth LE, rather than sending the signal through the backend. 
     With further reference to  FIG. 24 , in some embodiments the A/V recording and communication device  130 ,  330  may send a secondary registered user proximity determination signal  432  to the backend network device(s)  118 ,  120 . In response to receiving the secondary registered user proximity determination signal  432 , the network device(s)  118 ,  120  may similarly send a secondary registered user proximity determination signal  434  to the client device(s)  800  of one or more secondary users. In alternative embodiments, the A/V recording and communication device  130 ,  330  may send the secondary registered user proximity determination signal  432  directly to the client device(s)  800  of the one or more secondary users using a short-range communication protocol, such as Bluetooth or Bluetooth LE, rather than sending the signal through the backend. 
     In response to receiving the secondary registered user proximity determination signal  432 , the client device(s)  800  of the one or more secondary users may send a secondary registered user proximity response signal  436  to the backend network device(s)  118 ,  120 . In response to receiving the secondary registered user proximity response signal  436 , the network device(s)  118 ,  120  may similarly send a secondary registered user proximity response signal  438  to the A/V recording and communication device  130 ,  330 . In alternative embodiments, such as those in which the client device(s)  800  of the one or more secondary users receive the secondary registered user proximity determination signal  432  directly from the A/V recording and communication device  130 ,  330 , the client device(s)  800  of the one or more secondary users may send the secondary registered user proximity response signal  436  directly to the A/V recording and communication device  130 ,  330  using a short-range communication protocol, such as Bluetooth or Bluetooth LE, rather than sending the signal through the backend. 
     With further reference to  FIG. 24 , in response to receiving the primary registered user proximity response signals  428 ,  430  and/or the secondary registered user proximity response signals  436 ,  438 , the A/V recording and communication device  130 ,  330  may determine whether the primary registered user and/or the one or more secondary registered user(s) are located within the predetermined proximity to the A/V recording and communication device  130 ,  330  and, based on the determination, the A/V recording and communication device  130 ,  330  may send an alert signal  440  to the backend network device(s)  118 ,  120 . In response to receiving the alert signal  440 , the network device(s)  118 ,  120  may similarly send an alert signal  442  to the primary registered user&#39;s client device  800 . Examples of circumstances that might cause the A/V recording and communication device  130 ,  330  to send the alert signal  440  to the backend network device(s)  118 ,  120  (and cause the network device(s)  118 ,  120  to send the alert signal  442  to the primary registered user&#39;s client device  800 ) are discussed above. These examples include detecting that the primary registered user is not home (e.g., the primary registered user is not within the predetermined proximity), and/or detecting that one or more secondary users are home (e.g., the secondary user(s) is/are within a predetermined proximity of the A/V recording and communication device  130 ,  330 ), and also detecting one or more other conditions, such as a visitor approaching the A/V recording and communication device  130 ,  330 , or a suspicious person loitering or repeatedly passing by the A/V recording and communication device  130 ,  330 , etc. 
     With still further reference to  FIG. 24 , the arrows corresponding to the operational mode transition signals  420 ,  422 , the secondary registered user proximity determination signals  432 ,  434 , and the secondary registered user proximity response signals  436 ,  438  are represented with broken lines, indicating that these signals may not be included in some of the present embodiments. Further, although the arrows corresponding to the secondary registered user proximity determination signals  432 ,  434  are located beneath the arrows corresponding to the primary registered user proximity determination signals  424 ,  426 , it is to be understood that in some embodiments the secondary registered user proximity determination signals  432 ,  434  may be sent at substantially the same time as the primary registered user proximity determination signals  424 ,  426 . 
     As discussed above, the present disclosure provides numerous examples of methods and systems including A/V recording and communication doorbells, but the present embodiments are equally applicable for A/V recording and communication devices other than doorbells. For example, the present embodiments may include one or more A/V recording and communication security cameras instead of, or in addition to, one or more A/V recording and communication doorbells. An example A/V recording and communication security camera may include substantially all of the structure and functionality of the doorbell  130 ,  330 , but without the front button  148 , the button actuator  228 , and/or the light pipe  232 . 
       FIG. 25  is a functional block diagram of a client device  800  on which the present embodiments may be implemented according to various aspects of the present disclosure. The user&#39;s client device  114  described with reference to  FIG. 1  may include some or all of the components and/or functionality of the client device  800 . The client device  800  may comprise, for example, a smartphone. 
     With reference to  FIG. 25 , the client device  800  includes a processor  802 , a memory  804 , a user interface  806 , a communication module  808 , and a dataport  810 . These components are communicatively coupled together by an interconnect bus  812 . The processor  802  may include any processor used in smartphones and/or portable computing devices, such as an ARM processor (a processor based on the RISC (reduced instruction set computer) architecture developed by Advanced RISC Machines (ARM).). In some embodiments, the processor  802  may include one or more other processors, such as one or more conventional microprocessors, and/or one or more supplementary co-processors, such as math co-processors. 
     The memory  804  may include both operating memory, such as random access memory (RAM), as well as data storage, such as read-only memory (ROM), hard drives, flash memory, or any other suitable memory/storage element. The memory  804  may include removable memory elements, such as a CompactFlash card, a MultiMediaCard (MMC), and/or a Secure Digital (SD) card. In some embodiments, the memory  804  may comprise a combination of magnetic, optical, and/or semiconductor memory, and may include, for example, RAM, ROM, flash drive, and/or a hard disk or drive. The processor  802  and the memory  804  each may be, for example, located entirely within a single device, or may be connected to each other by a communication medium, such as a USB port, a serial port cable, a coaxial cable, an Ethernet-type cable, a telephone line, a radio frequency transceiver, or other similar wireless or wired medium or combination of the foregoing. For example, the processor  802  may be connected to the memory  804  via the dataport  810 . 
     The user interface  806  may include any user interface or presentation elements suitable for a smartphone and/or a portable computing device, such as a keypad, a display screen, a touchscreen, a microphone, and a speaker. The communication module  808  is configured to handle communication links between the client device  800  and other, external devices or receivers, and to route incoming/outgoing data appropriately. For example, inbound data from the dataport  810  may be routed through the communication module  808  before being directed to the processor  802 , and outbound data from the processor  802  may be routed through the communication module  808  before being directed to the dataport  810 . The communication module  808  may include one or more transceiver modules capable of transmitting and receiving data, and using, for example, one or more protocols and/or technologies, such as GSM, UMTS (3GSM), IS-95 (CDMA one), IS-2000 (CDMA 2000), LTE, FDMA, TDMA, W-CDMA, CDMA, OFDMA, Wi-Fi, WiMAX, or any other protocol and/or technology. 
     The dataport  810  may be any type of connector used for physically interfacing with a smartphone and/or a portable computing device, such as a mini-USB port or an IPHONE®/IPOD® 30-pin connector or LIGHTNING® connector. In other embodiments, the dataport  810  may include multiple communication channels for simultaneous communication with, for example, other processors, servers, and/or client terminals. 
     The memory  804  may store instructions for communicating with other systems, such as a computer. The memory  804  may store, for example, a program (e.g., computer program code) adapted to direct the processor  802  in accordance with the present embodiments. The instructions also may include program elements, such as an operating system. While execution of sequences of instructions in the program causes the processor  802  to perform the process steps described herein, hard-wired circuitry may be used in place of, or in combination with, software/firmware instructions for implementation of the processes of the present embodiments. Thus, the present embodiments are not limited to any specific combination of hardware and software. 
       FIG. 26  is a functional block diagram of a general-purpose computing system on which the present embodiments may be implemented according to various aspects of present disclosure. The computer system  900  may execute at least some of the operations described above. The computer system  900  may be embodied in at least one of a personal computer (also referred to as a desktop computer)  900 A, a portable computer (also referred to as a laptop or notebook computer)  900 B, and/or a server  900 C. A server is a computer program and/or a machine that waits for requests from other machines or software (clients) and responds to them. A server typically processes data. The purpose of a server is to share data and/or hardware and/or software resources among clients. This architecture is called the client-server model. The clients may run on the same computer or may connect to the server over a network. Examples of computing servers include database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. The term server may be construed broadly to include any computerized process that shares a resource to one or more client processes. 
     The computer system  900  may include at least one processor  910 , memory  920 , at least one storage device  930 , and input/output (I/O) devices  940 . Some or all of the components  910 ,  920 ,  930 ,  940  may be interconnected via a system bus  950 . The processor  910  may be single- or multi-threaded and may have one or more cores. The processor  910  may execute instructions, such as those stored in the memory  920  and/or in the storage device  930 . Information may be received and output using one or more I/O devices  940 . 
     The memory  920  may store information, and may be a computer-readable medium, such as volatile or non-volatile memory. The storage device(s)  930  may provide storage for the system  900 , and may be a computer-readable medium. In various aspects, the storage device(s)  930  may be a flash memory device, a hard disk device, an optical disk device, a tape device, or any other type of storage device. 
     The I/O devices  940  may provide input/output operations for the system  900 . The I/O devices  940  may include a keyboard, a pointing device, and/or a microphone. The I/O devices  940  may further include a display unit for displaying graphical user interfaces, a speaker, and/or a printer. External data may be stored in one or more accessible external databases  960 . 
     The features of the present embodiments described herein may be implemented in digital electronic circuitry, and/or in computer hardware, firmware, software, and/or in combinations thereof. Features of the present embodiments may be implemented in a computer program product tangibly embodied in an information carrier, such as a machine-readable storage device, and/or in a propagated signal, for execution by a programmable processor. Embodiments of the present method steps may be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. 
     The features of the present embodiments described herein may be implemented in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and/or instructions from, and to transmit data and/or instructions to, a data storage system, at least one input device, and at least one output device. A computer program may include a set of instructions that may be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program may be written in any form of programming language, including compiled or interpreted languages, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. 
     Suitable processors for the execution of a program of instructions may include, for example, both general and special purpose processors, and/or the sole processor or one of multiple processors of any kind of computer. Generally, a processor may receive instructions and/or data from a read only memory (ROM), or a random access memory (RAM), or both. Such a computer may include a processor for executing instructions and one or more memories for storing instructions and/or data. 
     Generally, a computer may also include, or be operatively coupled to communicate with, one or more mass storage devices for storing data files. Such devices include magnetic disks, such as internal hard disks and/or removable disks, magneto-optical disks, and/or optical disks. Storage devices suitable for tangibly embodying computer program instructions and/or data may include all forms of non-volatile memory, including for example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, one or more ASICs (application-specific integrated circuits). 
     To provide for interaction with a user, the features of the present embodiments may be implemented on a computer having a display device, such as an LCD (liquid crystal display) monitor, for displaying information to the user. The computer may further include a keyboard, a pointing device, such as a mouse or a trackball, and/or a touchscreen by which the user may provide input to the computer. 
     The features of the present embodiments may be implemented in a computer system that includes a back-end component, such as a data server, and/or that includes a middleware component, such as an application server or an Internet server, and/or that includes a front-end component, such as a client computer having a graphical user interface (GUI) and/or an Internet browser, or any combination of these. The components of the system may be connected by any form or medium of digital data communication, such as a communication network. Examples of communication networks may include, for example, a LAN (local area network), a WAN (wide area network), and/or the computers and networks forming the Internet. 
     The computer system may include clients and servers. A client and server may be remote from each other and interact through a network, such as those described herein. The relationship of client and server may arise by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
     The above description presents the best mode contemplated for carrying out the present embodiments, and of the manner and process of practicing them, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which they pertain to practice these embodiments. The present embodiments are, however, susceptible to modifications and alternate constructions from those discussed above that are fully equivalent. Consequently, the present invention is not limited to the particular embodiments disclosed. On the contrary, the present invention covers all modifications and alternate constructions coming within the spirit and scope of the present disclosure. For example, the steps in the processes described herein need not be performed in the same order as they have been presented, and may be performed in any order(s). Further, steps that have been presented as being performed separately may in alternative embodiments be performed concurrently. Likewise, steps that have been presented as being performed concurrently may in alternative embodiments be performed separately.