A credit card sized self powered smart sensor node

This paper reports a self powered smart sensor node (also called ‘smart tag’) consisting of a piezoelectric vibration energy harvester, a power conditioning circuit, sensors and an RF transmitter. The smart tag has dimensions similar to a credit card and can be easily integrated into various applications such as the surface of the aircraft. The smart tag is powered by an integrated bimorph piezoelectric generator that extracts energy from ambient vibrations. The generator is fabricated using thick film printing technology. Experimentally, the generator produced a maximum RMS output power of 240 μW when excited at vibration with a frequency of 67 Hz and peak amplitude of 0.4 g (3.9 m s−2). This generated power is sufficient to enable periodic sensing and transmission. Details of the experimental results of the piezoelectric generator and the power conditioning circuit are presented. Test shows that the waiting time of the system between two consecutive transmissions is around 800 s.