I would like to built a heart beat sensor (note: no, it is not an ECG) that sense the sound made from the heart (phonocardiography) and converts it in a digital signal.
I am writing here for suggestion about how to achieve it.
I did a little bit of researches and found that a heart beat should be around 10-15dB (source: The Decibel ). Actually an heart beat is made by 4 different sounds so i guess that the article refers to the most audible (S1) so for my application I think that would be good to aim at around 5dB.
I wasn't able to find a dedicated sound sensor (maybe i didn't search enough?), i found a few comparator or amplifier like the lm393 used in these application. Also on google i found the existence of Surface acoustic wave sensors (https://en.wikipedia.org/wiki/Surface_acoustic_wave_sensor) that maybe could suit my needs.
What i would like to do has been already done in digital stethoscopes (https://www.worthview.com/stethoscope-amplify-sound/).
Do you think that what i would like to do is feasible? how would you do it?
Thanks in advance