In this paper, we report an approach to measure mechanomyogram (MMG) using a MEMS pressure sensor. The sensor consisted of an open cavity and a micro piezo-resistive cantilever, which was placed at the cavity's opening. The sensor was attached on a subject's forearm to measure the emitted MMG when the subject was exerting forces with his/her arm. In the prototype sensor, the cavity had footprint radius of 5.5 mm and the height of 3 mm. The gap between the cantilever and the surrounding walls was downscaled to 2 μm to enable the sensor to measure low frequency sound pressure with high sensitivity. In experiments, we used an electromyogram recorder, a low frequency microphone and an electronic stethoscope, and based on the results taken with these conventional devices to evaluate our proposed sensor. The experimental results showed that the sensor was able to measure MMG with the maximum S/N ratio of 50.
