Wireless vehicle detection node based on tunnelling magneto resistance sensor

Wei Huang

School of Automation, Hangzhou Dianzi University, Hangzhou, China

A wireless node based on tunnelling magneto resistance sensor was designed for large scale vehicle detection in Intelligent Transport System. With regard to the sensor’s characteristic of high resistance, rapid response and high linearity, the signal acquisition and regulation circuits were designed to meet the requirement of geomagnetic measure for three dimension axis of the sensor. A vehicle noise pre-detection unit was implemented to wakeup the microcontroller from sleep state before vehicle enter the detection area. Low power chips were considered and the all sensor units were power supplied by MCU, cooperated with the improved power-efficient ATA algorithm, the power consumption was minimized. Experimental results showed that the designed node was capable of capturing the magnetic feature of different vehicle types and on line vehicle flow detecting for long time.