We present several findings related to acoustic emission detection using a MEMS sensor. The MEMS sensor is a
capacitive resonant transducer, fabricated in the PolyMUMPs process, with a resonant frequency near 160 kHz. In this
paper, the design, initial characterization, amplification electronics, and packaging of the sensor system are reviewed.
We present results from an experiment that compares the MEMS sensor system to a commercial PZT sensor by
comparing the response of each sensor to a pencil lead break on a plate. In addition, we describe the noise
characterization of the MEMS sensor system, comparing the predicted noise voltage to the measured value. This
analysis reveals that the electronic noise from the amplifier is significantly greater than the noise from the sensor,
suggesting that an amplifier with less noise would increase the sensitivity of the MEMS sensor system. We describe the
design of a new, transimpedance amplifier and its noise characterization, showing the new amplifier design has less
noise than the old design. The experiment comparing the commercial PZT sensor and the MEMS sensor system is
repeated using the new amplifier, and we present results showing an increase in sensitivity of the MEMS sensor system.
Finally, we present results from an experiment comparing the ability of the commercial PZT sensor and the MEMS
sensor system with the new amplifier to detect pencil lead breaks performed a large distance from each sensor.