Temperature based controller


I recently bought an Ardunio which I hope to use to control my home brewery.

Since I have never done this before, I thought I'd start with something fairly easy (temperature controller for the fermentor). I am fairly comfortable with coding in general, so I expect that side will easy enough to figure out.

I want to use a temperature sensor placed in the fermentor to control power to a fridge and heating pad to maintain optimal fermentation temperature. Basically I wanted to know if the Ardunio should have much trouble with doing this?

If anyone has any tips on what sort of sensors to use (as they will be submerged) that would be helpful to

That's actually a little trickier than you think: e.g., the heating pad will continue to emit heat for a little while after you switch it off, depending on where you apply the heat/cold it may take a little time for the cooler/warmer liquid to flow via convection and change the temperature of the whole mass.

But it's not rocket science, you can find some examples by searching the site for "pid control" and/or "temperature control" (using the boxes at the upper right on the forum and home pages), and it should be fun to experiment to find out where the lags in response and other quirks are so you can compensate for them (If it's not, you should definitely find a different first project ;)).


First, the Arduino should have no problem doing this... in fact, you are not the first... since I've seen that someone on one of the homebrewing forums I visit use an Arduino for just this purpose.

Second, I agree... the nature of the kind of "control" you need for the brewing processes really demands a PID type controller as has been mentioned.

Third, you need to decide what sensors you want. Thermistor, I2C, SPI and 1-Wire are all quite different and each wants their pound of flesh from your available code space. (Meaning, if you pick ANALOG like thermistor or LM35, stick with analog throughout... if you pick 1-wire... have all your sensors be 1-wire.) The physical distance between all of your sensors is really the best way to determine the proper sensor type. Raw Analog, I2C, and SPI are really best suited to sensors being 10ft or less from the controller... otherwise you are looking at a solution like Maxim/Dallas 1-wire chips.

Don't know much about it myself, but I would definitely check out the Halfluck website Google

WOW! Nice site. Thanks for finding that.

He uses 1-wire... btw.

Hi everyone,

Thanks for the suggestions :slight_smile:

I am looking forward to getting this to work.

Also check out this one: