Ultra-low-power RFID-based sensor mote

This paper deals with the design and implementation of flexible, fully integrated sensor motes for ubiquitous sensor networks based on a established, long-range RFID technology. The battery-less mote is made up of a single-chip solution incorporating a microwave RFID-front-end, an 8-bit microcontroller, a low-power temperature sensor, a reconfigurable sensor interface, a 10-bit SAR ADC, a full-fledged I²C digital interface and non volatile memory for program and sensor data. Overall power consumption lies under 7μW at a readout distance of 3 m. The temperature sensor works from -20 up to +60°C with a precision of +/-0.50°C and 16 bits resolution. A fully-passive demonstration system with external commercial sensors including pressure, humidity and acceleration sensors was implemented and tested.