Awesome! I attempted the same approach, but after discovering a cheap gas concentration sensor (MQ-135, tunable to CO2) I abandoned the audio approach for a minimum of data processing. I get very accurate bubble detection and highly recommend it :-)
Ooh that sounds very interesting, I'd be interested in how that works, do you put the co2 sensor near the airlock and notice 'peaks' of co2 from it, when bubbles come through.
Or is the sensor in the fermenter itself and you're kind of measuring the pressure?
I put it near the airlock and detect peaks. For now, the most valuable information I extract is when the fermentation starts and stops -- with notifications on my phone :-)
