Making your own booze includes a great deal of sitting around waiting on things to happen, like waiting on the fermentation process to surface so you can get on with bottling as well as drinking it. That includes watching the bubbles in the airlock: when the frequency of the bubbles falls below a specific level, your hooch is prepared for the next step.
[Waldy45] chose to automate this process by building a bubble catcher that steps the frequency of bubbles passing with the airlock. He did this utilizing an optocoupler, a combination of LED as well as light sensor that modifications resistance when something passes between them. You can’t see it in the image, however the horseshoe-shaped optocoupler is slotted around the thin neck in the bubble tube to sense when a bubble passes through.
The optocoupler is linked to an Arduino, running a bit of code that produces an interrupt when the optocoupler is triggered. At the moment, this just outputs an typical time between bubbles to the serial port, however [Waldy45] is looking to add an ESP8266 to wirelessly link the Arduino as well as get in touch with him when the bubble frequency falls, indicating that the booze is prepared for bottling.
We’ve seen a couple of over the top beer breweries before (here as well as here), however none of them have automated the actual fermentation stage, so something such as this would certainly be an addition. Cheers!