Making your own booze involves a lot of sitting around waiting for things to happen, like waiting for the fermentation process to finish so you can get on with bottling and drinking it. That involves watching the bubbles in the airlock: once the frequency of the bubbles falls below a certain level, your hooch is ready for the next step.
[Waldy45] decided to automate this process by building a bubble catcher that measures the frequency of bubbles passing through the airlock. He did this using an optocoupler, a combination of LED and light sensor that changes resistance when something passes between them. You can’t see it in the image, but the horseshoe-shaped optocoupler is slotted around the thin neck in the bubble tube to sense when a bubble passes through.
The optocoupler is connected to an Arduino, running a bit of code that generates an interrupt when the optocoupler is triggered. At the moment, this just outputs an average time between bubbles to the serial port, but [Waldy45] is looking to add an ESP8266 to wirelessly connect the Arduino and contact him when the bubble frequency falls, indicating that the booze is ready for bottling.
We’ve seen a couple of over the top beer breweries before (here and here), but none of them have automated the actual fermentation stage, so something like this would definitely be an addition. Cheers!