Embodiments of the present invention are related to wireless powered sensors.
Sensors for various uses are becoming common in everything from smart clothing to medical monitoring. Such sensors can be used for many purposes, including, for example, to monitor medical conditions such as activity trackers, heart rate, temperature, health conditions, blood alcohol levels, or other conditions. Similar sensors can also be used for monitoring environmental conditions such as temperature, fluid flow, light conditions, chemical compositions, or other conditions. However, current sensor technologies fall short of being fully compatible with daily use.
Although such a device can be embedded as wearables, it is difficult for the circuit board and the battery to be embedded with fabric or otherwise provided in a wet or otherwise adverse environment. Further, these devices tend to be uncomfortable, visually unattractive, and provide for waterproof and safety concerns, especially if battery 104 fails. Consequently, eventually devices such as device 100 become unusable. Furthermore, they are high cost devices. With much smaller lifetimes as the fabric in which they are embedded or the environment in which they are used is cleaned or otherwise maintained, or as is provided for other adverse environmental conditions where device 100 may be used, such devices can be very expensive to use.
Therefore, there is a need to develop better sensor technologies for wearable and other embeddable purposes or for sensors used in other environments.
In accordance with some embodiments of the present invention, a passive sensor unit that is powered wirelessly and communicates with a reader unit is presented. In some embodiments, a passive sensor unit includes a sensor; a receive coil; a circuit coupled to the sensor, the circuit configured to receive sensor data from the sensor; and a wireless power circuit configured to receive power from the receive coil and configured to provide power to the circuit, wherein the sensor unit is unpowered when power is absent from the receive coil.
A reader unit can include a power source; a transmit coil; a wireless power transmitter configured to receive power from the power source and configured to drive power to the transmit coil; a communications circuit coupled to the wireless power transmitter, the communications circuit coupled to the wireless power transmitter to transmit and receive data; and a processor coupled to the communications circuit, the processor coupled to send and receive data through the wireless power transmitter.
A sensor system can include one or more passive sensor units, each of the one or more passive sensors configured to receive wireless power from a receiver coil and communicate data through the receiver coil; and one or more reader units, each of the one or more receiver units configured to supply power and communicate with a set of the one or more passive sensor units.
These and other embodiments are further discussed below with respect to the following figures.
In the following description, specific details are set forth describing some embodiments of the present invention. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure.
This description and the accompanying drawings that illustrate inventive aspects and embodiments should not be taken as limiting—the claims define the protected invention. Various changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known structures and techniques have not been shown or described in detail in order not to obscure the invention.
Elements and their associated aspects that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be claimed as included in the second embodiment.
Some embodiments of the present invention can provide sensors for wearable technologies, medical technologies, shipping technologies, construction technologies and other areas with an easily produced and inexpensive passive sensor in combination with a wireless hub. The passive sensor and wireless hub separate the power source and controller portion with the passive sensor including a wireless power receiver coil and the sensor while the wireless hub includes the power supply. The two components cooperate to provide power for sensing and communicate to receive the day. In this fashion, for example the wearable device has a low-cost sensor portion that can be embedded into the wearable device and clothing. The detachable power source and controller can be detached while the wearable device is under conditions of wash or replacement.
Circuitry 122 can, for example, use an analog front end (AFE) 110 that receives, performs analog processing (e.g., filters, amplifiers, and other analog processing), and digitizes data received from sensor 108. The digitized data can be preprocessed by a digital signal processing (DSP) 112. A driver 114 can provide power and input signals to sensors in sensor block 108. Circuitry 122 can further include various power converters 150, power and temperature protection circuits 148, power regulation blocks 132, rectifier blocks 130, thermal control blocks 134, and status or power indicators 138. Furthermore, internal clocks 136 can also be included.
In addition, circuitry 122 can include a microcontroller 142 and memory 140. Microcontroller 142 can execute instructions for operating sensors 108, receiving data from sensors 108, storing sensor data, and providing sensor data to interfaces and communications 124. Microcontroller can execute instructions that are stored in memory 140.
Interfaces and communications 124 can include interfaces for communicating with an end user, either wired or wirelessly. As such, common interfaces include GPIO, I2C, or other interface methods.
As shown in
Reader unit 202 further includes a wireless power block 206 which, powered by power source 222, drives transmit coil 204. Wireless power block 206 include driver and switching technology to drive power into transmit coil 204. Any wireless power transfer system can work. For example, power may be transferred wirelessly using standards from the Wireless Power Consortium (WPC) or using standards from the Power Matters Alliance (PMA). Other methods of wirelessly transferring power may also be used.
A back-channel communications block 208 allows for communication of data through transmit coil 204 or through a magnetic secured data transmission through transmit coil 204 or a separate coil incorporated within transmit coil 204. The output power can be modulated, for example in frequency or amplitude, to transmit data and can be monitored to detect a modulation in the load to receive data. As such, communications block 208 can transmit instructions to and receive sensor data from a sensor 250 through the wireless power transfer. Any communication protocol can be implemented for communication of data between reader 202 and sensor 250.
Furthermore, reader 202 may include a user interface 234. User interface 234 may include interface devices such as, for example, displays for data presentation (e.g. screens or LED indicators), data input devices (e.g., keyboards, touchscreens, or other pressure or contact sensitive devices), and audio devices such as speakers. Any device and method for receiving instructions from and providing data to a user can be used.
Reader 202 may also include one or more interfaces in interface block 210. Such interfaces may include wireless and wired interfaces. For example, interface block 210 may include Bluetooth, low-energy Bluetooth (BLE), 6LoWPAN, ZigBee, near-field communication (NFC), or other wireless systems. Interface block 210 can also include wired interfaces such as, for example, I2C and GPIO systems, as well as other wireless data transmission systems can be used.
Further, reader 202 can include a microcontroller 218 coupled to memory 220 to control and operate reader 202. Memory 220 can be a combination of volatile (RAM) and non-volatile (ROM) memories which store programming that can be executed by microcontroller 218 as well as data. Microcontroller 218, executing instructions stored in memory 220, receives data through communications block 208, may provide processing for such data, and may store data in memory 220 and also supplies the data to UI 234. Microcontroller 218 may further supply data through interfaces 210, and may also receive updates to programming stored in memory 220 or perform other functions.
Sensor unit 250, as is illustrated in
Power is received through receive coil 252 by wireless power 254. Wireless power 254 includes circuitry to receive wireless power and provide power to all of the other components in sensor unit 250. As such, wireless power 254 can include rectifiers, filters, regulators, power converters, or other components to provide power to components.
Sensor unit 250 further includes back-channel communications 256, which transmits and receives data through receive coil 252. For example, data may be received by demodulating a signal transmitted on the power, for example by amplitude or by frequency modulation. Data can be transmitted, for example, by modulating the load on wireless power 254 (which can be detected by reader unit 202).
Sensor unit 250 may include a microcontroller 258 coupled with memory 260. Memory 260 may include volatile (RAM) or non-volatile (ROM) memory for storage of data and programming instructions. Microcontroller 258 controls communications through back-channel communications as well as to receive sensor data from sensor block 262 in order to supply that sensor data through back-channel communications 256 to a reader unit 202.
As discussed above, sensor unit 250 does not include an internal power source and therefore is only powered when it is proximate to a reader unit 202. As such, when reader unit 202 is brought close to sensor unit 250 and provides wireless power to sensor unit 250, sensor unit 250 powers up and processor 218 executes instructions to activate sensors in sensor block 262 and receive data from sensors. The data is then transmitted through back-channel communications 256 to reader unit 202. When reader unit 202 is removed from the vicinity of sensor unit 250, sensor unit 250 becomes inactive.
Processor 218, coupled to memory 220, is coupled to user interface 234 and to communications block 272. Data can be transmitted to sensor unit 250 through communications 272 by modulating the output power in modulation block 208. Data can be received from sensor unit 250 through communications 272 by demodulating the output power that has been modulated by sensor unit 250. Data communications through wireless power 206 can use any protocol. Communications 272 can further provide data to interface 210. Interface 210 can be coupled to an antenna 274 for wireless communications, and may also include wired communication. As discussed above, any wired or wireless communications protocol may be used.
A circuit diagram illustrating features of sensor unit 250 according to some embodiments is illustrated in
Processor 260 can also be coupled to driver 266, which provides voltages to power and operate sensors in sensor block 262. Data from the sensors in sensor block 262 can be received in analog-front-end (AFE) 264 for processing and digitizing. Data from AFE 264 is provided to processor 258. Processor 258 executes instructions to receive and process data from AFE 264 and to communicate the sensor data through communications 212. Processor 258 may also execute instructions to receive data, instructions, or programming updates from communications 212.
As is further illustrated in
In some embodiments, reader unit 202 and passive sensor unit 250 can operate with large separations, for example about 30 cm, in order to provide power and communications capability with passive sensor unit 250. Reader unit 202 may communicate with other devices at a distance of up to about 30 m with standards such as Bluetooth or 6LoWPAN, for example. Consequently, as shown in
Sensor 108 of conventional sensor system 100 is included in sensor unit 250 as sensor 262. Sensor 262 can be any sensor or, in some cases, combination of sensors. For example, sensor 262 can be one or more of a moisture sensor, a gas sensor, an optical sensor, a stress or strain sensor, a vibration sensor, flow sensor, or any other sensor. Sensor 262 depends on the application of passive sensor 250 and can be tailored for particular uses.
As is further illustrated in
Using reader units 202 as hub units, a complex network of sensor units 250 can be constructed.
In one example, sensor units 250 can be wearable sensors. Wearable sensors can have receive coils 252 printed on a flexible substrate, which can be included into fabric materials. A hub reader unit 202 can also be worked into a wearable medium while being in contact with one or more of the wearable sensor units 250. In another example, one or more sensor units 250 can be applied in an environmental or medical application and monitored by a hub reader unit.
As discussed above, sensor unit 250 includes circuitry 304 for signal conditioning and wireless power reception, which can be provided on a single circuit board or multiple circuit boards embedded with receive coil 252. Sensor unit 250 does not contain a battery and is actively powered by a reader unit 202. When the sensor unit 250 is powered, the sensors included in sensor unit 250 takes measurements and uses in-band communication to communicate with reader unit 202. Reader unit 202 includes a wireless power transmitter, a transceiver to send and receive in-band communications, and contains a power supply (battery or other source of power) to power the system and supply power to the wireless transmitter. Reader unit 202 may also include additional components, including flash memory to store received messages and a wireless or wired communication system to communicate information received from the sensor cube to a computer, mobile phone, or other device.
Sensor 262 of sensor unit 250 can be a flow sensor, a thermopile, a temperature sensor, an optical sensor, or any other type of sensor. Wireless power transmitted from reader unit 202 to sensor unit 250 can be magnetic resonance, magnetic induction, or radiofrequency. Range (the distance between reader unit 202 and sensor unit 250) can be from contact or near-contact to a significant distance, depending on application, power requirements, and wireless power system implemented.
As is discussed above, sensor unit 250 has minimal functionality, and can be disposable—all of the power and more complicated hardware is in reader unit 202. In addition, sensor unit 250 does not include a battery and may have limited capabilities, sensor unit 250 can be designed for high-temperature, low-temperature applications, or other applications in adverse environments where a battery might not work.
In some embodiments, sensor unit 250 may be a disposable unit and and/or may be embedded within a component of a system, which itself may be disposable. In some medical applications, sensor unit 250 may be implanted or may be wearable in some fashion.
Passive sensor units 250 can, for example, be formed on a continuous tape of sensors that then can be attached to items of clothing, materials for construction, in packaging to track shipping conditions, or used in other areas where sensing is useful. In some embodiments, passive sensor units 250 can be incorporated within any packaging or other system.
As such, sensor systems as illustrated in the systems described above have a large number of applications. For example, passive sensor units 250 can be used in medical sensors where the passive sensor unit 250 is disposable and a reader unit 202, whether operating as a hub or operating as a mobile unit, is used to periodically read passive sensor unit 250.
Several system use examples for systems involving reader unit 202 and sensor unit 250 according to embodiments of the invention as described above are provided below. These example use cases are not exhaustive and one skilled in the art will realize other uses for systems according to these embodiments. These examples are provided for instruction only and are not intended to be limiting.
Smart clothing can be devised for various applications. For example, smart diapers can include sensor units 250 with moisture sensing sensors. Smart clothes can be equipped with sensors to monitor the activity of the wearer, including physical activity with kinematic sensors, temperature, moisture, heart rate, oxygen levels, or other attributes. In some applications, smart clothes can be equipped with gas sensors, radiation sensors, or other environmental sensors to monitor for dangerous environmental conditions.
Smart clothing, for example, can have one or more sensor units 250 with a perspiration or heartbeat or chemical sensors built in to monitor exercise. Reader unit 202 can act as a hub and be clipped on to the collar or other part of the clothing to activate and monitor the built-in sensor units 250. Reader unit 250 can include sufficient flash memory in memory 220 to store the measurement data so that the person can work out without carrying a cell phone or otherwise being within range of a device in communication with reader unit 202. In addition, reader unit 202 can be removed after exercise and attached to a different piece of smart clothing while the first piece of clothing is in the laundry and thereby interact with a different set of sensor units 250.
Sensor units 250 can also be used for food package monitoring, transport tracking, component tracking, and other applications. For example, a sensor unit 250 where sensor 262 includes a temperature sensor can be placed on or in a piece of meat or other food. When the food is placed in an oven, a reader unit 202 remaining outside of the oven can provide real-time information on the food temperature to a cook, even when placed in a microwave oven. Such a sensor unit 250 can be a one-time use sensor.
Another potential use can be for filter monitoring, monitoring the flow and chemical composition of the fluid or gas being filtered in the filter and thereby determining when the filter needs changing. Sensor units according to the present invention can be used to monitor building structures for moisture, structural parameters (stress and strain conditions of various components), detection of various gasses, and other conditions. Such construction monitoring can be useful in marine or aerospace construction as well as in building structures and can be used to periodically monitor various aspects of ships, boats, aircraft, or spacecraft.
In another example system, a sensor unit 250 can be built into an IV drip tube. Reader unit 202 can, in some examples, be snapped onto the tube of the IV to provide real-time measurement (and potentially management) of IV flow. When the IV is no longer needed, reader unit 202 can be snapped off and attached to another system, while the IV tube with sensor unit 250 can be discarded.
In another example use, sensor units 250 where sensors 262 include moisture sensors can be placed into a field where soil moisture is to be measured (e.g., an agricultural field). Reader unit 202 can be a drone equipped with GPS. Reader unit 202 can then be sent to each sensor in turn to obtain moisture measurements from each sensor. The drone with reader unit 202 could land on (or hover near) each sensor unit 250, wirelessly provide power to that sensor unit 250, collect the data from that sensor unit 250, and then fly to the next sensor unit 250.
The above detailed description is provided to illustrate specific embodiments of the present invention and is not intended to be limiting. Numerous variations and modifications within the scope of the present invention are possible. The present invention is set forth in the following claims.
The present disclosure claims priority to U.S. Patent Ser. No. 62/506,434, filed on May 15, 2017, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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62506434 | May 2017 | US |