Combination of hybrid energy harvesters with MEMS piezoelectric and nano-Watt radio wake up to extend lifetime of system for wireless sensor nodes

Power consumption is a critical issue in Wireless Sensor Networks(WSN) applications and typically the energy consumed by the wireless communication dominates. Reducing the WSN node activity and the communication energy can extend the lifetime of the node considerably. This work presents a direct application approach to extend the lifetime of a wireless senor node using a MEMS piezoelectric energy harvesting device in combination with a nano-Watt wake-up radio receiver, in order to build an efficient power device. The design of the power device will be connected to each node as a normal battery bringing the wake-up radio capabilities. Two scenarios were implemented to use the power unit as a wireless switch with harvesters, or to use the power management wake up polices while the MEMS piezoelectric harvester was designed as a power supply directly to the wake up radio receiver. The experimental results and characterization of the muW-MEMS harvester are presented. Finally, measurements on a generic node present the benefits of this approach bringing the power consumption in low power mode down to nano-Watt level (zero power) when the node is not needed in the application.