DIY Auto Temp Control


 
K

Ken Harrod

New member
Hello, I have been checking out this site for a couple years. It has been very informational and has helped me out a lot.

I did some searching on the internet about Automatic Temperature Control Systems to see if there were any DIY kits out there or other options. I found one, that I did not find talked about on here.

Circuit Celler DIY Temp Control

The system seems simple enough to build (assuming you have soldering experience). The processor for the circuit can be found for less than $5. I priced out all the circuit components and it was under $40. I did not check the price on the housing, switch, thermocouples. I would guess the total price would end up being less than $100. The guy posted the code for the processor also, and there are various compilers out there for free that will compile it.

Has anyone tried building this device? Any comments?

I think it might end up being a winter project for me. Maybe not as refined as the commercial units, but I am not that refined either.
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Seems like a pretty reasonable design although I don't believe his measurement graph. There is no way one gets a ruler flat stability like he is showing.

As for comments, it is hard to come ahead cost wise if you consider your time to build and debug this. And consider that it does a lot less than stoker.
 
The flat line temperature for his cooker is surprising to me, too. I figure a big part of that is due to the better insulating properties of his ceramic cooker. Then again, I have seen pretty constant temps on my WSM and I do not have any form of automatic temperature control, yet.

I do think the Stoker seems to be the best overall package right now. But, I am the type of person who likes to tinker and build things. I am likely to build one, just to say I did. And... then I would probably turn around and buy the Stoker so I can monitor my cooker via the internet while I am at work or in the house on my PDA and stay out of the rain.

On this DIY model, if I read the article right, you can monitor the device via a serial cable. That would not allow me to monitor with my PDA or from work, but it would allow me to monitor the cooker from inside the house.

Time wise, I think it would take a couple hours to solder up the pieces to a board and have it running. I also found an "education board" that already has that microprocessor, the MAX 232 and a few other components mounted. With that "education board" it might just be a matter of plugging in the thermocouples, adding the A/D circuit and plugging in the display. That board has a socket already for the display. The "education board" was $35.

If I ever try it out, I will post my results on here and pass on how much work it was and if it was worth the effort.
 
I have been saying for a couple months that an arduino could do this task, that is the Atmel processor.

I need to read that closer to see where I can get those probes, but have been thinking to cannibalize a meat probe to see if I can attach a couple wires on it.

Anyone know where to get the probes at?

And the arduino triggers 5v devices, which a computer fan would work fine for, AFAICT.
 
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Alan D:
I have been saying for a couple months that an arduino could do this task, that is the Atmel processor.

I need to read that closer to see where I can get those probes, but have been thinking to cannibalize a meat probe to see if I can attach a couple wires on it.

Anyone know where to get the probes at?

And the arduino triggers 5v devices, which a computer fan would work fine for, AFAICT. </div></BLOCKQUOTE>

The end of his article he lists http://www.omega.com/ as the source he used for the k-type thermocouples.

I have not searched through the site yet to find any thermocouples, though. I have a few thermocouples here that go with some meters I have, I thought I would use them initially just for testing.

I have found a few "educational boards" that use the atMega8 processor. They already have the processor, the MAX232, the programming connector, the power supply circuit and some other features. Here is one I was looking at... http://www.futurlec.com/ATMega8_Educational_Tips.shtml

and another http://mcuboards.ecrater.com/product.php?pid=2028435

Those boards would really speed up the building of this device.

I also found a radio transmitter/reciever that will transmit a serial port communications stream. It is only $18. This design has a serial port for data logging, so this radio frequency board would allow you to wirelessly monitor it in you home at your computer.
 
This site will supply a bare circuit board that already has the circuits printed on it to support the processor, msx232 serial communications chip, the programming connection etc... Plus is has a pretty big "prototyping" area that would work great for the extra circuits needed for the Automatic Temp control specific features.

I think these education or project boards would help make a cleaner more professional look. The fact they already have all the connections for the processor and the serial communications really eliminates a LOT of the work.

The radio frequency adapter can be gotten from HERE. You will need to scroll to the bottom of the page. You would need two of those interface boards, one for the temp controller at your smoker and a second one in your house connected to your computer.

I have a laptop, so I would probably just hook my laptop up to the devices serial port and then access the data from my desktop and the wireless network in my home. the radio wireless serial link would just be fun to try.

I am guessing it could be done for about $80. That's pretty close to the price of the Pit Minder ($150), but this one will also monitor 3 food thermocouples and gives you the data logging ability.

Plus, it has the fun factor and all the conversations at the cookouts saying, "yeah, I built that thing".
 
FYI, I have a cermaic smoker I use with stoker and despite it being superb from efficiency and stablity point of view, it still will not flatline. I get close to 1% accuracy but not over a long period.
 
About 2 years ago I did some extensive research on this topic as I wanted to build one myself. These guys have been around a while. I like what they are doing, but I'm too lazy go as far as they did. I went the easy way out on mine and used USB based devices that are already built. I wrote a Visual Basic application to read the boards and control servos and fans to control temperature. This isn't something I'm trying to sell, so I hope it's OK to post my web page:
http://www.geekwithfire.com
I'm not trying to promote anything, just gathering suggestions and opinions.
 
Josh,

I like what I saw on your site. Do you have more info on the boards you are using? It seems to be a lot simplier (and cheaper) having the computer doing all the control and monitoring instead of another piece of electronic gizmo .
 
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ken Harrod:
Josh,

I like what I saw on your site. Do you have more info on the boards you are using? It seems to be a lot simplier (and cheaper) having the computer doing all the control and monitoring instead of another piece of electronic gizmo . </div></BLOCKQUOTE>

Yea, that's why I'm not selling it. At the end of the day, when you have everything you need, it isn't much cheaper if at all than the stoker or the guru. All of my boards are from a company called phidgets (www.phidgets.com); purchaced domestically from a company called Trossen Robotics. The only unique benefits my system has are that I can use cheap thermistors as well as thermocouples, can control an unlimited number of smokers, and can read from an unlimited number of probes. But, I mostly use thermocouples and that has gotten expensive.
 
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