Bioacoustic sensor system for automatic detection of bowel sounds

This study presents a bioacoustic sensor system developed for early detection of the recovery of bowel activity after abdominal surgery and to perform analysis on bowel sounds. Different than other studies, in order to be able to attenuate noise, two capacitive microphones oriented in opposite directions are used. Bowel sounds are typically observed at a frequency between 100 Hz and 1500 Hz and amplitude between 0 and 20mV. The signal strength is boosted 48 times with an amplifying circuit. The second microphone is used to observe environmental noise such as examination room noise. Both signals are digitized using an ADC (NI DAQ Data Acquisition USB 6009). Finally, we developed a software that can extract spectral properties of the signal and present the results in real time.