Hardware design of WSN node based on MEMS sensors

WU Yan， DONG Lin-xi
（College of Electronic Information， Hangzhou Dianzi University， Hangzhou 310018， China）

Abstract： In order to solve the problems of monitoring the healthy and safety of the buildings，the micro-electro-mechanical system（MEMS） technology and wireless sensor network technology were investigated. The structure and working principle of the accelerometer with the actuators droved by Lorentz force for increasing the initial sensing capacitance were introduced. Then the capacitance detection circuit was designed. ANSYS simulation software was used to evaluate the performance and Multisim was used to simulate the detecting circuit. The results show that the sensor could detect the three-dimensional acceleration signal；its static sensitivity can be 0.558 μm/g；the dynamic measurement range is  10 g； and the output is in accord with the simulation result. The hardware of the wireless sensor network node was designed which was constructed by MSP430F1611 as MCU，chip CC2430 was used to realize the wireless transceiver and some interface circuits around to monitor the displacement signal. With the inner temperature sensor to test，the results show that the nodes can realize the monitoring and meet the system design requirements.
Key words： capacitive accelerometer；wireless sensor network node（WSN）；MSP430F1611；CC2430；micro-electro-mechanical system（MEMS）