Energy harvesting using piezoelectric igniter for self-powered radio frequency (RF) wireless sensors

The field of miniature low-powered and low cost wireless sensor nodes has been growing tremendously and the wireless sensor nodes have been widely used in applications like medical implants, embedded sensors in building, military applications, etc. However, little research works have been carried out on the energy sources of the wireless sensors such that the sensor nodes become self-powered. This paper discusses various renewal energy sources available in the environment that can be tapped to supply energy for these wireless sensors. This paper has special interest on piezoelectric generator because it is simple and easy to harvest mechanical force energy from human beings as compared to other energy sources. An energy harvesting circuit design for piezoelectric pushbutton-generator is proposed and implemented efficiently for wireless radio frequency (RF) transmitter. This self-powered wireless transmitter is capable of transmitting a 12-bit digital word information using the mechanical force energy harvested from depressing the pushbutton which is attached to the energy harvesting circuit. The experimental results show that when the piezoelectric pushbutton is depressed, 67.61 mu J of electrical energy is scavenged and it is sufficient to transmit 2 complete 12-bit digital word information via the RF unit. The RF unit consumes 26.4 mu J of energy for 1 word transmission.