An attempt at counting bubbles from an airlock with sound

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chris2012
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An attempt at counting bubbles from an airlock with sound

Post by chris2012 » Thu Jul 13, 2017 9:03 am

https://www.anfractuosity.com/projects/bubbleometer/ - I've just been working on this little project recently to count the bubbles from an airlock and graph them, so you can very roughly see the fermentation activity.

If anyone happens to work with signal processing, I'd be very interested in ways to improve it!

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basswulf
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Re: An attempt at counting bubbles from an airlock with soun

Post by basswulf » Thu Jul 13, 2017 6:04 pm

Looks fascinating. If live processing is too demanding or you want to optionally keep data, you could probably store and queue smaller blocks. You could also experiment with using lower resolution recording or lossy compression - the signal to noise ratio looks pretty good so you've probably got a lot more resolution than you need and are making your system work on higher volume data than it needs to get the required result.

If you have sufficient processing capacity, it would be useful to also get a parallel visual signal - do bubbles you see correspond with bubbles you hear? It would be interesting to also take temperature readings - I'd expect the bubble activity to correlate with the temperature bump that comes from active fermentation (unless your fermenting environment is strictly temperature controlled).

Wulf

guypettigrew
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Re: An attempt at counting bubbles from an airlock with soun

Post by guypettigrew » Thu Jul 13, 2017 8:38 pm

Absolutely astoundingly clever way of monitoring fermentation.

My approach is similar, but much more primitive. I stand in front of the fermenter, often with a pint in hand, and count the bubble rate.

When it gets really slow I give it another 24 hours then start to chill it down.

Guy

chris2012
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Re: An attempt at counting bubbles from an airlock with soun

Post by chris2012 » Thu Jul 13, 2017 8:52 pm

Guy - Nice, everything's better with a pint in hand :)

Wulf - yeah I've been told by someone else also that the sample rate is probably unnecessarily high, so I'll have to investigate different rates.

I was fermenting with a fridge + heater and an Inkbird, with the cooling/heating differential set to 0.5C. But I will definitely have to overlay my temperature information on the bubble graph to see if there's any interesting patterns like you say.

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