Fermilab

I inherited an old POS fridge this past weekend. The door seals are not great, but it makes cold air and was free, so I can't complain. I'm now using it as a fermentation chamber.

I didn't have any spare A419's laying around to control the temps, but I do have a linux server, a DS18S20, one of these and various relays laying around. I hacked up the wiring and wrote a q&d script that gets fired up by a cron job. It works, but it's kludge. I ordered some 1-wire relays yesterday, but they take a while to show up (the free samples from maxim).

Since this is a fermentation chamber, and it's being controlled by hacked together spare parts, I've dubbed it "Fermilab".

My questions are:

• I poked around looking for process control software. I don't seem to find much, but from the rocket science chatter I see being bantered about here, I must presume that I've missed something. Certainly I'm not the first to fool around with 1-wire and brewing, and as I approach 50, I care less and less about writing the stuff myself. I'd much prefer to find some gpl project that does this already.
  
  
• The fridge is in questionable shape. The frame is bent - it's not "square". As such, the door doesn't hang straight and it doesn't really seal like it should. It's almost there, but not quite. I'm not sure if it's important being a fermentation chamber (allowing co2 to vent) or if I should strip the coils out of that fridge and build a new chamber out of foam board. However, I've never stripped coils from a fridge - I've seen a few pics around here, but it does give me the willies a bit.

 

http://www.homebrewtalk.com/f51/arduino-ds18b20-hd44780-218222/

I'd say that the better that you can eal that chamber, the better off you'll be. I wouldn't worry about venting CO2, but rather the electricity use from a non-sealed fridge.

 

Yes, Arduino is interesting, but not what I'm looking for. I'm not looking for an embedded solution. I'm after process control on linux using 1-wire. Fedora 14 using owfs specifically.

Yea, not easily done. Fixing that fridge doesn't seem possible (I've already done what can be done). Perhaps it's for not though. Over the past few days it's been running 6-8 minutes per hour during the day when outside temps are mid 80's. It came on last night at ~10 pm for 2 minutes and hasn't been on since (now 8:30am).

 

BTW, I'm after process control sw because I plan on doing much more with this than turning on/off a fridge...

 

That's probably a roll your own type system there. I can't imagine it being more than a couple hundred lines of shell scripting or so, even for fairly complex process control.

You could probably string in some other process control software somewhat easily.

 

One would think.... but finding "other" process control software that operates with 1-wire (and doesn't cost arm/leg) seems to be far and few between. For now, I guess I'll just stay with shell scripts and throw the data into RRDtool to play with later.

 

I completely thought this thread was going to be about http://en.wikipedia.org/wiki/Fermilab. Keep us updated on how this goes, I'm interested in building a system from similar parts some day.

 

Sagan,

That's the play on words I was after. I'm an astronomy/physics geek so when I read/hear "ferm" I always think of Fermilab.

Until my dalsemi relays show up, I'm using one of these: http://www.electronickits.com/kit/complete/elec/ck1601.htm. If you can read and perform some very basic soldering, the kit is the way to go. My soldering skills are just above basic, and I had no issues at all.

The control software is something I wrote years ago - if anyone has this relay board (or buys it) I can post the control software (I GPL'ed it many moons ago). It's linux code, so no peaking through Windows.