ArduinoMania

The team behind BrewPi are at it again! This time they have created an online guide showing how to convert a min-fridge into a Raspberry Pi & Arduino controlled fermentation chamber. In it, they describe 3 possible options:

• Option 1: Make a simple switched power cord, without hacking into the fridge electronics.
• Option 2: Make a switched power cord, but also override or remove the thermostat.
• Option 3: Rip out the thermostat and fully integrate the SSRs into your fridge (which is what [Koen] and [Elco] did).

First things first though. They had to clean the fridge. And depending on they got it or how long it has been unplugged for, the inside might have been pretty rank and disgusting from mold growing out of every corner. This took a good hour or so to clean properly lest the brewing process get infected with external grossness. This is all worth it because a well-controlled fermentation chamber results in a superior batch of beer.

With cleaning behind them the team added some temperature sensors to measure the beer and fridge levels. [Koen] and [Elco] suggest using the OneWire distribution board that comes with their BrewPi kit for this. Then, the cables were routed through the fridge and take control of the compressor.

Because [Koen] and [Elco] decided to go with the SSR method, the good news was: they didn’t need to hack into the start relay, and just left it as it is. But, they did need to gain access to the compressor and make a few changes. For one, the two SSR’s will be added with one of the AC terminals connected to LIVE (brown) and the other to the heater and the compressor.

No matter which method is chosen though, the end product will allow anyone to monitor and easily control the temperature range of your micro-brew, along with being able to log data and produce web-embedded graphs like the one shown below. It works by using the Arduino attached to run the temperature control algorithm autonomously. And, the Raspberry Pi adds stability.