Commence Fermentation!

It's been a few weeks but I've managed to get a bunch of work done on the Web UI and the actual management code of the chamber. I finished wiring everything up shortly after the last post and did some tests with a carboy of water. I replaced the ceramic heating bulb with a small Ceramic heater as the bulb was causing a localized hotspot that was melting the foam of my chamber wall, and the Ceramic heater has a built in fan to help push the hot air around the chamber and get it up to an equalized temperature that much more quickly. Since I don't have a working touchscreen for the Beaglebone Black at the moment I've decided to whip up a web page to display data and manage the set point. I built a MySQL database and a simple front-end which allows the temperature monitoring code to push temperature data into the database on a set interval. I then used Google's really awesome graphing UI to draw some pretty graphs on the website. Here's a screencap of it in action.

Super cool Fermentation graph!

The blue line represents the ambient temperature in the chamber and the red line is a measurement from a probe stuck directly into the wort. The wort temp probe controls the heating element, when it drops to 0.3 degrees below the setpoint the heating element is turned on. The heater has a built in thermostat which was originally at 55 degrees C or so, so that's why you see those peaks on the blue chart, I turned it down to 30 degrees and I can see a pretty good response from the wort. That graph is a live view of a 20 gallon ferment from this weekends brewing, so there is a pretty big thermal mass in there and it takes about an hour to raise the wort temperature 1 degree C. I also have a cooling circuit, if the wort ever goes 0.3 degrees above my set point the Beaglebone Black will turn on the cooling circuit and a 5k BTU air conditioner will blast the chamber with cold air to keep the wort at the desired temperature. All the code for the temperature monitor is available on my Github repo Temp Driver Repo I've still got some work to do to pull down the set point from the website, right now it's hard-coded and I haven't found an elegant way to pull that data down yet. The plan is to have ferm schedules, where it will hold at temp x for some time, then ramp up or down to a set point and hold, then cold crash etc. I'll post some pictures of the whole system in action once I've cleaned up the garage a bit.