i need a few tips on the best approach for analyzing the sound of a heartbeat. the sound is grabbed by a microphone hooked to a stethoscope. the results of the analysis will be used to switch light bulbs on and off in an installation.
here is the tricky part : anybody in the audience can hook to the stethoscope in order to trigger the lights, which means a lot of interferences will be caused by the manipulation of the stethoscope. so here is my question : how would you go for separating in a subtle manner the "noise" from the heartbeats ? the thing is that human heartbeats range between 50 and 200Hz and may vary from person to person ( in speed and amplitude ). Manipulating a microphone also causes some noises in the low frequency range.
any help will be much appreciated, thanks in advance