A 3-axis accelerometer and strain sensor system for building integrity monitoring

An Ultra-Low-Power readout architecture for capacitive MEMS-based accelerometers and strain sensors is presented. The system can read both accelerometers and strain sensors in a half-bridge configuration. The gain is controlled by integrating pulses from the excitation voltage allowing accurate control of the Signal-to-Noise ratio. A Figure-of-Merit of 4.41×10⁻²⁰ F√(W/Hz) was achieved for a sensor range of ±2.0g and ±20,000µε over a 100Hz bandwidth. Residual motion artifacts are also cancelled by the system.