Handheld reader communicating with a RFM3250 temperature sensor
Our sensors harvest energy from radio frequency (RF) signals emitted by a reader. The reader, which itself runs on batteries or line voltage, sends commands (using RF signals) to the sensor instructing the sensor to perform some task, such as executing a sense function or reporting back its unique Electronic Product Code (EPC). The sensor decodes and executes the command, and then reports its information back to the reader using its own antenna. The sensor data is backscattered to the reader – meaning it is sent to the reader by reflecting a continuous RF signal sent by the reader.
When the entire transaction is completed, the sensor powers down. In this sense, the sensor does not constantly run—it only takes measurements when it receives a command from the reader. However, the reader can be programmed to query the sensor at regular intervals to create a regular flow of data.