Patent Publication Number: US-2016223390-A1

Title: Wireless sensing device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 104103717, filed on Feb. 4, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a sensing technology and more particularly relates to a wireless sensing device. 
     2. Description of Related Art 
     In surveying various resources and environment on Earth, wireless sensing devices all play an indispensable role. Generally, researchers dispose a large quantity of wireless sensing devices in the environment desired to be surveyed so as to perform long-term data collection. The wireless sensing devices then return the collected sensing data back to control centers on land, thereby allowing researchers to analyze or adjust the wireless sensing devices in response to the actual state of the environment to be surveyed. Therefore, concerning long-term surveying and data analysis, the way of managing the power of the devices and enhancing the accuracy of the sensing data is always a major subject in terms of the design of wireless sensing devices. 
     SUMMARY OF THE INVENTION 
     The invention provides a wireless sensing device, which generates electrical energy through an energy harvesting circuit and detects a change in the environment sensed through a sensor, thereby effectively managing the power of the wireless sensing device and enhancing the accuracy of sensing data. 
     The wireless sensing device of the invention includes a vibration plate, an antenna, a sensor, an energy harvesting circuit and a data processing circuit. The antenna and the sensor are disposed on the vibration plate. The sensor generates a sensing data according to the vibration of the vibration plate. The energy harvesting circuit generates an electrical energy in response to the vibration of the vibration plate. The data processing circuit is coupled to the sensor and the antenna, and the data processing circuit is operated by the electrical energy to store the sensing data, or to transmit the sensing data through the antenna. 
     In an embodiment of the invention, the wireless sensing device enables the data processing circuit through the electrical energy, thereby allowing the data processing circuit to be switched between a detection mode and a transmission mode. In addition, under the detection mode, the data processing circuit activates the sensor through the electrical energy and stores the sensing data generated from the sensor. Under transmission mode, the data processing circuit transmits the sensing data through the antenna. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic block diagram of a wireless sensing device according to an embodiment of the invention. 
         FIG. 2  is a schematic block diagram of an energy harvesting circuit according to an embodiment of the invention. 
         FIG. 3  is a schematic block diagram of a data processing circuit according to an embodiment of the invention. 
         FIGS. 4 and 5  are a front view and a side view illustrating a configuration structure of an antenna and a sensor respectively according to an embodiment of the invention. 
         FIGS. 6 and 7  are a front view and a side view illustrating a configuration structure of an antenna and a sensor respectively according to another embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is a schematic block diagram of a wireless sensing device according to an embodiment of the invention. As shown in  FIG. 1 , the wireless sensing device  100  includes a vibration plate  110 , an antenna  120 , a sensor  130 , an energy harvesting circuit  140  and a data processing circuit  150 . The antenna  120  and the sensor  130  are disposed on the vibration plate  110 . Moreover, the sensor  130  generates a sensing data according to a vibration of the vibration plate  110 . 
     For instance, the sensor  130  can be a micro-electro-mechanical system (MEMS) sensor, in which the MEMS sensor may include a gyroscope and an accelerometer, etc. Thus, when the vibration plate  110  generates the vibration in response to the environment sensed, the sensor  130  detects an amount of change in vibration frequency, and acceleration, etc. of the vibration plate  110 . The sensing data generated by the sensor  130  therefore includes vibration frequency data and acceleration data, etc. In other words, with the vibration of the vibration plate  110 , the sensor  130  disposed on the vibration plate  110  detects a change in the environment sensed, and thus enhancing the accuracy of the sensing data. 
     The energy harvesting circuit  140  is connected to the vibration plate  110  and generates an electrical energy P in response to the vibration of the vibration plate  110 . In other words, the energy harvesting circuit  140  converts mechanical energy in the environment into electrical energy, thereby providing the electrical energy P (such as a power source, a power signal, or a power voltage, etc.) required by the wireless sensing device  100 . Thus, the wireless sensing device  100  self-generates the electrical energy P needed by the internal elements (such as the sensor  130  and the data processing circuit  150 ) through the energy harvesting circuit  140 , thereby effectively managing a power of the wireless sensing device  100 . 
     For instance,  FIG. 2  is a schematic block diagram of an energy harvesting circuit according to an embodiment of the invention. The energy harvesting circuit  140  includes an energy converter  210  and an energy capture unit  220 . Moreover, when the sensing environment changes, such as a flowing fluid (such as air and water) in the environment to be sensed, the flow  201  of the flowing fluid drives the vibration plate  110  to generate a back and forth vibration along a direction  202 . Furthermore, the energy converter  210  has a contact portion  211 . When vibration is generated by the vibration plate  110 , the stress generated from the collision between the vibration plate  110  and the contact portion  211  of the energy converter  210  will be received by the energy converter  210  thereby deforming. 
     In other words, the vibration of the vibration plate  110  provides a stress, namely mechanical energy, to the energy converter  210 , and the energy converter  210  converts that stress into an electrical signal, namely electrical energy. In addition, the energy capture unit  220  adjusts the electrical signal, so as to convert the electrical signal into the electrical energy P required by the wireless sensing device  100 . For instance, the energy capture unit  220  includes, for example, a full bridge rectifier and a filter capacitor in order to filter and rectify the electrical signal, thereby generating the stable electrical energy P. 
     Still referring to  FIG. 1 , the data processing circuit  150  is electrically connected to the antenna  120  and the sensor  130  disposed on the vibration plate  110 . In addition, the data processing circuit  150  is operated by the electrical energy P to selectively store the sensing data or to transmit the sensing data through the antenna  120 . In other words, the way the sensing data being processed (i.e., being stored or transmitted through the antenna) is controlled in accordance with the electrical energy P as an electric signal. In an embodiment, the wireless sensing device  100  further includes an energy storing element  160 , in which the energy storing element  160  can be a battery and can be used to store the electrical energy P. 
     It is worth noting that, in regard with the management of power, the wireless sensing device  100  enables the data processing circuit  150  through the electrical energy P, thereby allowing the data processing circuit  150  to be selectively switched between a detection mode and a transmission mode. Under the detection mode, the data processing circuit  150  activates the sensor  130  according to the electrical energy P, and stores the sensing data generated from the sensor  130 . While the data processing circuit  150  is operating in the transmission mode, the data processing circuit  150  transmits the sensing data through the antenna  120 . 
     For instance,  FIG. 3  is a schematic block diagram of a data processing circuit according to an embodiment of the invention. The data processing circuit  150  includes a transceiver  310 , a switching element  320 , and a controller  330 . The wireless sensing device  100  enables the controller  330  through the electrical energy P, thereby allowing the data processing circuit  150  to be selectively switched between the detection mode and the transmission mode. Further, the switching element  320  receives the electrical energy P and selectively transmits the electrical energy P to the transceiver  310  or the sensor  130  according to a control signal CT 3  generated by the controller  330 . 
     More specifically, while the data processing circuit  150  is operating in the detection mode, the controller  330  controls the switching element  320  by using the control signal CT 3  having a first level, such that the switching element  320  transmits the electrical energy P to the sensor  130  to activate the sensor  130 . Meanwhile, the sensor  130  is being operated by the electrical energy P, so as to generate a sensing data DS 3 . Whereas, while operating in the detection mode, the controller  330  stores the sensing data DS 3  from the sensor  130  in order to collect other sensing data. In another aspect, while operating in the transmission mode, the controller  330  controls the switching element  320  by using the control signal CT 3  which has a second level, such that the switching element  320  transmits the electrical energy P to the transceiver  310  to activate the transceiver  310 . At the mean time, the transceiver  310  is being operated by the electrical energy P, so as to transmit the sensing data DS 3  through the antenna  120 . 
     In other words, in regard with the management of the power, the wireless sensing device  100  first activates the controller  330  in the data processing circuit  150  through the electrical energy P, and then activates the sensor  130  or the transceiver  310  through the controller  330 , so as to allow the wireless sensing device  100  to selectively perform a sensing operation in the detection mode or a transmission operation in the transmission mode. Moreover, while the energy harvesting circuit is  140  continuously supplying the electrical energy P, the wireless sensing device  100  alternately and repeatedly performs the sensing operation in the detection mode and the transmission operation in the transmission mode. In addition, when the energy harvesting circuit  140  stops generating the electrical energy P, the data processing circuit  150  switches to a sleep mode to reduce power consumption of the wireless sensing device  100 . In other words, the wireless sensing device  100  further manages the power through the switching of the modes. 
     It is worth noting that, in practice, the wireless sensing device  100  can be regarded as a data transmission relay station. Therefore, when the wireless sensing device  100  is applied to a wireless local area network, the controller  330  can be a network processing unit (NPU). Additionally, the transceiver  310  may transmit the sensing data DS 3  through wireless communication protocols, such as wireless local area network, Bluetooth, Zigbee, etc., in the IEEE 802.11 standard. 
       FIGS. 4 and 5  are a front view and a side view illustrating a configuration structure of an antenna and a sensor, respectively, according to an embodiment of the invention. The energy converter  210  is positioned above the vibration plate  110 , and an orthogonal projection of the energy converter  210  on the vibration plate  110  is shown as the broken line  410 . Besides, the antenna  120  can be a printed antenna that is printed on the vibration plate  110  through a manner of printing. In addition, as shown in  FIG. 4 , an orthogonal projection of the printed antenna on the vibration plate  110  and the orthogonal projection of the energy converter  210  on the vibration plate  110  do not overlap with each other, so as to prevent the printed antenna colliding with the energy converter  210 , thereby preventing the printed antenna from being deformed or parted. 
     In another aspect, the data processing circuit  150  is electrically connected to the sensor  130  through a wire  420  disposed on the vibration plate  110 . Moreover, an orthogonal projection of the wire  420  on the vibration plate  110  and the orthogonal projection of the energy converter  210  on the vibration plate  110  do not overlap with each other, so as to prevent the wire  420  from colliding with the energy converter  210  and thus being deformed or parted. The orthogonal projection means that the projection lines of the wire  420  and the energy converter  210  are perpendicular to a projection plane of the vibration plate  110 . That is, the wire  420  is projected on the projection plane of the vibration plate  110  along a direction perpendicular to the projection plane to form the orthogonal projection on the vibration plate  110 . Similarly, the energy converter  210  is projected on the projection plane of the vibration plate  110  along the direction perpendicular to the projection plane to form the orthogonal projection on the vibration plate  110 . 
     In addition, the antenna  120  and the wire  420  are disposed at two sides of the vibration plate  110  so as to electrically connect to the data processing circuit  150 . For instance, the two sides of the vibration plate  110  have a bent portion  430  and a bent portion  440 , respectively. The bent portion  430  and the bent portion  440  respectively form an angle  05  with a body portion  450  of the vibration plate  110 . Moreover, a part of the antenna  120  is located at the bent portion  430  of the vibration plate  110 , and a part of the wire  420  is located at the bent portion  440  of the vibration plate  110 . It is worth noting that the data processing circuit  150  is positioned above the body portion  450  of the vibration plate  110 . For instance, the data processing circuit  150  can be positioned above or within the energy converter  210 . Moreover, the antenna  120  disposed at the bent portion  430  and the antenna  120  disposed at the body portion  450  are respectively positioned on different horizontal planes through adjustment of the angle θ5. Therefore, disposing a part of the antenna  120  on the bent portion  430  facilitates the electrical connection between the antenna  120  and the data processing circuit  150 . Similarly, disposing a part of the wire  420  on the bent portion  440  of the vibration plate  110  facilitates the electrical connection between the wire  420  and the data processing circuit  150 . 
       FIGS. 6 and 7  are a front view and a side view illustrating a configuration structure of an antenna and a sensor, respectively, according to another embodiment of the invention. The energy converter  210  is positioned above the vibration plate  110 , and an orthogonal projection of the energy converter  210  on the vibration plate  110  is shown as the broken line  610 . Moreover, the antenna  120  can be a stamped antenna. In other words, the antenna  120  can be formed metal components being made via a stamping process, thereby strengthening the structure of the antenna  120 . Therefore, in practical applications, the energy converter  210  can be directly colliding with the stamped antenna. 
     For instance, referring to  FIGS. 6 and 7 , the stamped antenna is directly fixed on the vibration plate  110  and faces the energy converter  210 . In other words, the orthogonal projections of the stamped antenna energy converter  210  on the vibration plate  110  are partially overlapped. In practical applications, as shown in  FIG. 7 , the contact portion  211  of the energy converter  210  directly collides with the stamped antenna. While comparing to the printed antenna in  FIGS. 4 and 5 , there is no need to avoid the collision between the energy converter  210  and the stamped antenna, the volume of the wireless sensing device  100  can be reduced and thereby miniaturized. In another aspect, the data processing circuit  150  is electrically connected to the sensor  130  through a wire  620  disposed on the vibration plate  110 . The orthogonal projection of the wire  620  and the energy converter  210  on the vibration plate  110  do not overlap with each other, so as to prevent the collision between the wire  620  and the energy converter  210 , that causes deformation or fracture. 
     In summary of the above, the wireless sensing device of the invention generates the electrical energy through the energy harvesting circuit in response to the vibration of the vibration plate. In other words, the wireless sensing device self-generates the electrical energy through the energy harvesting circuit and effectively manages the power by switching to different modes according to the electrical energy. Moreover, the sensor in the wireless sensing device is disposed on the vibration plate, such that with the vibration of the vibration plate, the sensor disposed on the vibration plate detects a change in the sensing environment, and thus enhancing the accuracy of the sensing data. 
     Although the present invention has been described with reference to the above embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the invention.