Antenna used in RFID tags powers tiny computers
SOURCE: “A Wirelessly Powered Platform for Sensing and Computation” Josh Smith
Paper accepted for the Eighth International Conference of Ubiquitous Computing, September 17-21, Orange County, CA
RESULTS: Using the same approach that makes passive RFID tags come to life when scanned, Josh Smith, an Intel researcher, has built a sensor that can collect environmental information and transmit it without a battery.
WHY IT MATTERS: Sensors that collect and transmit information are useful in many applications, such as tracking the temperature of food shipments. But most sensors require batteries; often, when the battery dies, the sensor needs to be replaced. Battery-free sensors could last much longer.
METHODS: The sensor uses an antenna similar to those found in battery-free RFID tags. When the sensor comes within range of an external device called an RFID reader, which emits radio waves, the antenna and circuitry harvest power from the radio signal to turn the sensor on. As long as the reader is within the antenna’s range, the sensor collects and processes environmental information. The brain of the device is a microcontroller, requiring less than a milliwatt of power, that contains a 16-bit processor, eight kilobytes of flash memory, and 256 bytes of random-access memory.
NEXT STEPS: Currently, the sensing device must be within a meter of the reader to work, but Smith says that with minor changes to the way the microcontroller processes the data, the range can be extended to three meters or more. He and his team are also looking into integrating the micorcontroller and antenna into a single chip to shrink the device.