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Homebrew fermentation temperature controller

Started by jimox, Sep 04 2012 04:50 PM

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9 replies to this topic

#1 jimox

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Posted 04 September 2012 - 04:50 PM

I am starting a project to control fermentation temperatures inside of a chest freezer. I know we have a lot of homebrewers who use the netduino and was wondering if anyone would be willing to share what they have done already. At the moment I am thinking of going with a DS18B20 https://www.sparkfun.../products/11050 one wire temperature probe (yes I know it will require using the beta http://forums.netdui...-onewire-alpha/ firmware). What I am still having trouble with is deciding on the relays to control the freezer. This is really where I am mostly looking for input. I am in the US so the relays will need to be able to control a 120VAC outlet which the freezer will plug into (I also have a heating element that I will ultimately be controlling also). If anyone out there has any suggestions or better yet some code/pics/wiring diagrams that would be greatly appreciated. Thanks.

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#2 jimox

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Posted 05 September 2012 - 02:31 PM

Ok, I just found these https://www.sparkfun.../products/11042. I know that my freezer pulls 12A on start-up so I would need to solder directly to the board on the load side. Does anyone see any issues with using these?

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#3 yyrkoon

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Posted 05 September 2012 - 11:04 PM

Ok, I just found these https://www.sparkfun...products/11042. I know that my freezer pulls 12A on start-up so I would need to solder directly to the board on the load side. Does anyone see any issues with using these?

jimox, the link you provided issues a 404 page not found web error. However I would like to add that I would be very interested, in what you come up with. We're 100% off-grid here, using solar to charge our batteries . . . and run a chest freezer off our inverter. Have been considering doing something like this myself, but for the purpose of shutting off the AC outlet at the freezer when battery voltage gets too low.

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#4 neslekkim

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Posted 06 September 2012 - 10:23 AM

just remove the last dot in the url: https://www.sparkfun.../products/11042 I'm using this for controlling my fridge, and are preparing another one for an chest freezer. In an similar project I'm toying with (controlling boiler), I'm going to use an solid state relay: http://www.ebay.com/...r-/300725964851 I hope it will work, at least it seems much simpler and safer than an coil based relay, and with that price..

--
Asbj�rn

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#5 jimox

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Posted 06 September 2012 - 12:53 PM

jimox, the link you provided issues a 404 page not found web error. However I would like to add that I would be very interested, in what you come up with. We're 100% off-grid here, using solar to charge our batteries . . . and run a chest freezer off our inverter. Have been considering doing something like this myself, but for the purpose of shutting off the AC outlet at the freezer when battery voltage gets too low.

I have fixed the link. After doing some research (and after the reply from neslekkim) I think I will try using them. If I can find the time I will breadboard it out this weekend and give it a try. I'll let you know how it goes.

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#6 jimox

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Posted 06 September 2012 - 12:57 PM

just remove the last dot in the url: https://www.sparkfun.../products/11042
I'm using this for controlling my fridge, and are preparing another one for an chest freezer.

In an similar project I'm toying with (controlling boiler), I'm going to use an solid state relay:
http://www.ebay.com/...r-/300725964851
I hope it will work, at least it seems much simpler and safer than an coil based relay, and with that price..

I thought about going with an SSR but I wanted something dead simple (a kit) to start with and the SSR kit at sparkfun doesn't have a high enough amperage. If all works well I will make one for my keezer also. What did you use for your temperature probe?

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#7 neslekkim

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Posted 06 September 2012 - 01:29 PM

Since I havent tried the ssr yet, I was hoping it was dead simple, it have same input and output as an relay, but it is optically isolated, and you don't get trouble for coil induction etc, and it have proper screw terminals which is good for the high voltage and currents, the printboard is probably ok, but as they write, solder the wire instead of using the wire terminals, since those that comes with it is not rated for this current. the complete controller I use already have an probe with it, cheap&complete (they have models for us market and so on also, The things I refer to are 220volt since I live in Norway) For the other project i have various probes, i havent found witch to use yet, but I bought this https://www.adafruit.com/products/381 and would guess it should be ok for lower temps, for boiler I think I will look at this: https://www.adafruit.com/products/642 , but I need to find out if it is food safe first. This project is of good use to find ideas for good sensors, how to attach them and so on, but probly overkill for your keezer/fermentation fridge. I guess you know this, but make sure that you do control your freezer/fridge properly, when switching the compressor on and off, you need to give it time to rest between each time, or otherwise you will soon have an heavy boat anchor..

--
Asbj�rn

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#8 jimox

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Posted 06 September 2012 - 02:07 PM

Since I havent tried the ssr yet, I was hoping it was dead simple, it have same input and output as an relay, but it is optically isolated, and you don't get trouble for coil induction etc, and it have proper screw terminals which is good for the high voltage and currents, the printboard is probably ok, but as they write, solder the wire instead of using the wire terminals, since those that comes with it is not rated for this current.

the complete controller I use already have an probe with it, cheap&complete (they have models for us market and so on also, The things I refer to are 220volt since I live in Norway)

For the other project i have various probes, i havent found witch to use yet, but I bought this https://www.adafruit.com/products/381 and would guess it should be ok for lower temps, for boiler I think I will look at this: https://www.adafruit.com/products/642 , but I need to find out if it is food safe first.

This project is of good use to find ideas for good sensors, how to attach them and so on, but probly overkill for your keezer/fermentation fridge.

I guess you know this, but make sure that you do control your freezer/fridge properly, when switching the compressor on and off, you need to give it time to rest between each time, or otherwise you will soon have an heavy boat anchor..

I looked at your probe for the boiler and I expect it will be food safe. The cable is PTFE (teflon) which according to http://www.homebrewt...on-tape-231217/ is food safe. The only thing you should check on before you go with it is what they use to seal the ss tube to the wire and make sure it is food safe.

I am planning on programming a minimum delay between switching the relays to prevent premature wear. I am thinking of setting it at 10 minutes.

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#9 neslekkim

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Posted 06 September 2012 - 02:20 PM

yes, 10 minutes is what I use on my controller, which seems to be ok. It's not necessary wear, but it's an vacuum pump, so it need to level out the vacuum.. (one of these days I want to find out how I can use the compressor for other stuff like vacuumpump or other things.. )

--
Asbj�rn

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#10 Coding Smackdown

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Posted 12 September 2012 - 09:47 PM

I bought several of the relays for SparkFun to do just what your talking about and they work fine for things like the fridge, freezer and pump motors. I wouldn't try to drive a Water Heating element with them though. I was searching for a good thermocouple/thermistor for one of my mod projects and found that Brewer's Hardware have several different types you could purchase that work OK. I just stay away from the temp probes for the Brewtroller since they use One-Wire support and right now the Netduino does not support One-Wire communications without dropping back to version 4.1. I found out that they have both Positive and Negative temperature coefficient temp probes so you might want to call them to make sure you get one that is a negative coefficient probe and then you can use any of thermistor code out on the arduino forums to read the probes. I've also posted a lot about my Netduino Brewing Projects out on my site http://diybrewery.com and am in the process of putting together a book on my projects. Good Luck! I'm looking forward to what you come up with.