So I’ve spent a few weekends the last couple months trying to get the control system on the Conviron kegerator worked out. I wanted to use some of the PID controllers I bought, but they seem limited in they don’t have a on-time delay and off-time delay, no ramp/soak and limited output options. I don’t want to short cycle the compressor, so controlling the on and off times and delay between is a must.
When I was first planning the build, I looked into some other software that does controls for homebrewers. There’s Craftbeerpi, Brewpi and a few others. I stumbled upon another software that runs on the Raspberry pi, that was geared more towards plant and mushroom growth, called MyCodo, by Kyle Gabriel. I was hesitant at first because I don’t have experience with the DS18B20 temperature sensors.
So after months of tinkering, I decided to give it a shot and I’m really glad I did. Not only did it eliminate my problems, but it has some features that I really wanted to have. It turns the kegerator into a full temperature controlled chamber, with a receptacle inside I can control on and off if needed. I can control the heating and cooling solenoids on the heat pump, the compressor and fan, and display humidity, temperature etc. depending on sensors used.
One really awesome thing it can do, is use methods to change the PID setpoint over time, i.e. ramp/soak profiles for lagering and cold crashing.
I wired it to drive some SSR’s directly to control the compressor/fan at the same time, and heating/cooling solenoids independently as needed. I know the kegerator won’t need heating, but it’s just another cheap SSR, so I’ll wire it in and if I need it, it’s there. Once I prove it out, I’ll gut the controls on my other Conviron chamber, and overhaul it. Chamber 2 already has Temp, humidity and light control which I want to keep. The thought is, I can use it for fermenting as well as growing mushrooms, growing plants, etc.
Here’s a picture of the MyCodo interface showing some of the outputs, temperature and the graphing abilities: