Abstract: An electronic system includes a reader and a remotely powered and remotely interrogated sensor transponder. The sensor transponder includes a coil or an antenna, a switched reactance circuit, a processor, and a sensor. The sensor transponder receives power radiated from the reader to the coil or antenna. The sensor uses the power for sensing. The sensor transponder is capable of processing sensor data in the processor and transmitting the sensor data to the reader using the switched reactance circuit. In one embodiment, the receiver coil or antenna is part of a resonant tank circuit which includes an impedance matching circuit. The impedance matching circuit is connected to the receiver coil or antenna to provide greater current to the sensor or other power-using device than would be available to the sensor or other power-using device if the sensor or other power-using device were connected between the first and second end. The impedance matching circuit can be two or more taps to the coil or antenna.

Abstract: A device for powering a load from an ambient source of energy is provided. The device includes an energy harvesting device for harvesting energy from the ambient source of energy wherein the rate energy is harvested from the ambient source of energy is below that required for directly powering the load. A storage device is connected to the energy harvesting device. The storage device receives electrical energy from the energy harvesting device and is for storing the electrical energy. A controller is connected to the storage device for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the load when the stored energy exceeds a first threshold. The system can be used for powering a sensor and for transmitting sensor data, such as tire pressure.

Abstract: A device for powering a load from an ambient source of energy is provided. The device includes an energy harvesting device for harvesting energy from the ambient source of energy wherein the rate energy is harvested from the ambient source of energy is below that required for directly powering the load. A storage device is connected to the energy harvesting device. The storage device receives electrical energy from the energy harvesting device and is for storing the electrical energy. A controller is connected to the storage device is for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the load when the stored energy exceeds a first threshold. The system can be used for powering a sensor and for transmitting sensor data, such as tire pressure.

Abstract: An electronic system includes a reader and a remotely powered and remotely interrogated sensor transponder. The sensor transponder includes a coil or an antenna, a switched reactance circuit, a processor, and a sensor. The sensor transponder receives power radiated from the reader to the coil or antenna. The sensor uses the power for sensing. The sensor transponder is capable of processing sensor data in the processor and transmitting the sensor data to the reader using the switched reactance circuit. In one embodiment, the receiver coil or antenna is part of a resonant tank circuit which includes an impedance matching circuit. The impedance matching circuit is connected to the receiver coil or antenna to provide greater current to the sensor or other power-using device than would be available to the sensor or other power-using device if the sensor or other power-using device were connected between the first and second end. The impedance matching circuit can be two or more taps to the coil or antenna.

Abstract: A device for powering a load from an ambient source of energy is provided. The device includes an energy harvesting device for harvesting energy from the ambient source of energy wherein the rate energy is harvested from the ambient source of energy is below that required for directly powering the load. A storage device is connected to the energy harvesting device. The storage device receives electrical energy from the energy harvesting device and is for storing the electrical energy. A controller is connected to the storage device is for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the load when the stored energy exceeds a first threshold.

Abstract: A sensing device includes a Wheatstone bridge and a source of a stimulation configured to apply the stimulation across two electrodes of the Wheatstone bridge. The device also includes a timing sensitive circuit configured to detect timing of a signal appearing across one of the other electrodes of the bridge as a result of the stimulation being applied. The timing provides a way to read the sensor. The device can be powered remotely and data so read can be transmitted using the remote power. The timing sensitive circuit includes a comparator. The comparator provides a high logic signal for a time related to the reactance of one leg of the Wheatstone bridge, and that provides a reading of a differential sensor having elements in each leg of the bridge.

Abstract: A sensing device includes an RFID chip and a differential variable reluctance transducer (DVRT) sensor that can be read remotely with electromagnetic power provided to the device from a remote reader. The ac signal provided to the device by inductance is used for powering the RFID chip and exciting the sensor. Data read from the sensor can also be transmitted back to the reader using the power provided by the reader. The sensor circuit uses a lower amount of current than the RFID chip, so it does not contribute appreciably to device power requirements.

Abstract: A sensing device includes a Wheatstone bridge and a source of a stimulation configured to apply the stimulation across two electrodes of the Wheatstone bridge. The device also includes a timing sensitive circuit configured to detect timing of a signal appearing across one of the other electrodes of the bridge as a result of the stimulation being applied. The timing provides a way to read the sensor. The device can be powered remotely and data so read can be transmitted using the remote power. The timing sensitive circuit includes a comparator. The comparator provides a high logic signal for a time related to the reactance of one leg of the Wheatstone bridge, and that provides a reading of a differential sensor having elements in each leg of the bridge.

Abstract: A sensing device includes a Wheatstone bridge and a source of a stimulation configured to apply the stimulation across two electrodes of the Wheatstone bridge. The device also includes a timing sensitive circuit configured to detect timing of a signal appearing across one of the other electrodes of the bridge as a result of the stimulation being applied. The timing provides a way to read the sensor. The device can be powered remotely and data so read can be transmitted using the remote power. The timing sensitive circuit includes a comparator. The comparator provides a high logic signal for a time related to the reactance of one leg of the Wheatstone bridge, and that provides a reading of a differential sensor having elements in each leg of the bridge.

Abstract: A sensing device includes a Wheatstone bridge and a source of a stimulation configured to apply the stimulation across two electrodes of the Wheatstone bridge. The device also includes a timing sensitive circuit configured to detect timing of a signal appearing across one of the other electrodes of the bridge as a result of the stimulation being applied. The timing provides a way to read the sensor. The device can be powered remotely and data so read can be transmitted using the remote power. The timing sensitive circuit includes a comparator. The comparator provides a high logic signal for a time related to the reactance of one leg of the Wheatstone bridge, and that provides a reading of a differential sensor having elements in each leg of the bridge.