A Self-powered Wireless Air Flow And Temperature Monitoring Node Driven By Wind Energy

It is important to research the self-powered wireless wind speed and temperature monitoring node, which can be applied to the environment monitoring, ventilation system, and so on. Based on the previous works, the micro piezoelectric wind energy harvester was designed, which can scavenge the wind energy and measure the wind speed at the same time. The harvester consists of a reed with two parallel piezoelectric layers. One of the piezoelectric layer is used as the electrical source to power the wireless monitoring node, and the other functions as an air flow sensor to measure the wind speed. Therefore, the operational mechanisms of wind energy harvesting and wind speed measuring were introduced. And the circuit for frequency and temperature measurement was designed. Furthermore, a self-powered wireless monitoring node for the measurement of the wind speed and temperature was developed.The main activities include:① Based on the advance in the wind energy harvester and air flow sensor, a self-powered wireless air flow and temperature monitoring node with the wind energy harvester was proposed.② The operation mechanisms of the wind energy harvesting and wind speed measuring were introduced for the harvester with a resonant cavity. The relationship between wind speed and the natural frequency of the cantilever beam was simulated by using ANSYS software, and the influence of structure parameters was also analyzed.③ A circuit for frequency and temperature measurement was designed. Based on the IAR Embedded Workbench, the program was written and verified.④ A self-powered wireless air flow and temperature monitoring node was fabricated and tested. Experimental results show that, at wind speed of 11.1 m/s, the output voltage was about 10.4 V and the output power of the harvester was about 1.21 m W for the electrical load of 25 k?, which was sufficient to power the wireless monitoring node to measure and transmit the data every 45 s. When the wind speed increased from 7 m/s to 12.4 m/s, the self-powered wireless monitoring node worked normally. The sensitivity of the air flow sensor was about 1.22 Hz/(m/s).