Development of a vibration-powered wireless temperature sensor and accelerometer for health monitoring

This paper describes and evaluates the continued development of a prototype vibration-powered, wireless sensor for use in condition based maintenance (CBM) applications. To reduce installation and maintenance costs, the CBM industry is turning interest increasingly toward wireless, self-powered sensors, but a major impediment to more widespread implementation has been a lack of sensors that can scavenge enough energy to operate as well as their battery or wall-powered equivalents. The sensor described in this paper solves that problem by implementing low-power electronics and improved energy scavenging technology. Developed by RLW, Inc. of State College, PA, the S⁵ NAPtrade sensor runs off power scavenged from the ambient vibrations of the platform to which it is attached. It acquires temperature and acceleration measurements and communicates them wirelessly via a radio. It runs indefinitely, reporting its temperature and acceleration every fifteen minutes, if vibration levels of the machine to which it is mounted are 0.065 g RMS or greater at the internal generator´s resonant frequency (50 and 60 Hz described in this testing). Upon cessation of input vibration energy for power, the S⁵NAPtrade uses up remaining available energy before going to sleep until energy is again available at a future time