The Research On Key Technology Of Piezoelectric Self-powered Wireless Sensor Network Nodes

According to the shortage problem of the energy supply in each node ofwireless sensor networks, a design method based on the self-powered mode wire-less temperature sensing system was put forward. At present, the energy shortageproblem of sensor networks in practical applications is serious, chemical batte-ries are now widely used in sensor network node for energy source, these chemi-cal battery reserve power is limited, which can not provide long-term power forsensor nodes, a method of regular battery replacement of the battery powersupply was put forward to meet the shortfall, but doing so is not only a waste ofresources but also increase system expenses. Facing the consumption problem ofsensor energy source, a self-powered wireless temperature sensing system waspresented in this paper, which converts mechanical vibration energy into electricenergy for the sensor node to supply energy. The method not only replace thetraditional battery to make it work without need for long-term maintenance,while also reduce energy waste.A self-powered wireless temperature sensing system was designed in thepaper, which converted mechanical vibration energy into electric energy by usingpiezoelectric effect to power the system, the principle of the piezoelectric genera-tor was theoretical analyzed and its power was calculated. The design of wirelesssensor network nodes was completed. A MSP430microcontroller, a quartz tuningfork temperature sensor and a NRF24L01wireless module were used in thehardware circuit. First of all, mechanical vibration energy were converted intoelectric energy by piezoelectric plate and piezoelectric energy converter, the elec-tric energy was stored by a super capacitor, and then the MSP430microcontroller,the quartz tuning fork temperature sensor and the NRF24L01wireless modulewere powered by the power management module. The frequency signal was sentto the MSP430microcontroller, which was converted from ambient temperatureby the use of frequency-temperature conversion. Finally, the temperature signal was wirelessly transmitted by NRF24L01module, and then the wireless mea-surement of the temperature was finished.An IAR integrated development environment was used in the system. C lan-guage was used to design application program, system software design was fi-nished, and the corresponding experimental platform was built to test the system.The experiment results show that the piezoelectric chip LTC3588-1can convertvibrated mechanical energy into power supply of3.3V supply voltage,100mAcurrent and330mW power, which can supply low-power wireless temperaturesensor system. The temperature data which was measured by the quartz tuningfork temperature sensor can be sent accurately by the wireless module. The de-sign of the piezoelectric self-powered wireless temperature sensing system wasachieved successfully.