Self-powered heat-sink SoC as temperature sensors with wireless interface: Design and validation

We present the design and the proof of concept of a self-powered System-on-Chip temperature sensor with wireless communication interface integrated in the shape of a heat-sink. The proposed solution is based on a thermo-harvesting module that scavenges the energy required to operate from the target device under monitoring. The heat-sink provides optimal thermal dissipation while the SoC underneath provides feedback on the temperature. The thermal gradient between the chip and the environment is converted into electrical energy that supplies the wireless interface to send a beacon message to a receiver. The packet rate is directly related to the temperature of the target device by means of the efficiency curve that characterize the thermo-harvesting module. We designed the proposed SoC architecture and we proved the concept using commercial devices. We validated our approach comparing simulated results with real experiments. The prototype system has been proven effective to measure the temperature on the package of a general purpose ARM CPU in the range 40°C to 70°C.