Application of Single MEMS-accelerometer to Measure 3-axis Vibrations and 2-axis Tilt-Angle Simultaneously

Santoso, Didik R; Maryanto, Sukir; Nadhir, Ahmad

This paper discusses about a technique to developing an integrated sensor system for measuring mechanical vibrations in 3-axis and tilt angle in the 2-axis simultaneously, using single MEMSaccelerometer, i.e. MMA7361L. The MMA7361L is an analog accelerometer with maximum sensitivity of 800 mV/g. This device has 3-channels output voltage (Vx, Vy, Vz) in response to the acceleration “g” of each axis corresponding work (gx, gy, gz). By using certain techniques in the design of signal conditioning circuits, then the MMA7361L can used to detect 3-axis vibration and 2-axis tilt angle at the same time. To accommodate the 5-signals from output of the sensor system, is constructed a data acquisition system based on PIC16F876 microcontroller, which provides 5-channels internal ADC with 10 bits resolution. Thus, the resulting integrated sensor system becomes very simple and inexpensive. Results of experiment show that the developed sensor system has proven having good performance. For the vibration sensor,
voltage gains can be set up to 60 dB (800 V/g) with low-level noise. While the tilt sensor is capable of detecting up to ± 30 angle on the non-linearity of 4.5% (max), with average resolution of about 0.06 degrees.

Keywords: Integrated Sensor, Vibration, Tilt-Angle, MEMS-Accelerometer