Awesome, Inexpensive DIY ATC

I just completed my DIY Temp Controller. I had most of the parts to build the enclosure and the fan and wiring. Had to purchase the PID Controller, thermocouple, fuse holder, terminal strip, and one of the switches. In the end it cost me about $55. I figure it would cost close to $95-$100 for the whole thing as long as you could come up with some scrap conduit.

Here's what I did:

First, I used a non-metallic outdoor junction box as the enclosure. I used a 12V PID Controller from www.auberins.com to control my 12V fan from an old PC. I wired in a fuse to protect the PID Controller and used a 12V transformer to power the unit. I can hook it to a car battery when camping as well.



I used some scrap pieces of 1" emt conduit to bring the air in the enclosure and to carry it to the smoker. I drilled holes for the set screw connectors for the conduit, bent the conduit on the inlet side to keep water out, and bent the conduit on the outlet side to mount to my smoker adapter.



I puchased the thermocouple from Auber Instruments as well. I drilled a hole in the middle section of my WSM to accept the thermocouple, painted the exposed metal with black high heat enamel paint, and attached the thermocouple with the nut supplied on the inside of the middle section. I installed it just below the upper cooking grate. The thermocouple can be bent to reach above the cooking grate if I decide later.



I fabbed the adapter for the air inlet out of my daughter's dog's water dish so I had to replace that. I noticed that it looked very similar to the adapter that you can purchase for a Stoker. I cut a hole for the set screw connector and attached the conduit. I then drilled a hole in the adapter and used a toggle bolt to attach the adapter to the charcoal bowl.

Inside the enclosure I cut grooves down the sides with my Dremel to slide a piece of cut sheet metal in to create two separate chambers. I cut a hole in the metal for the fan and mounted the fan with screws. I used silicone around the edge of the metal divider and on the conduit connectors and wire entrance/exit to seal everything up. The lid of the enclosure has a rubber gasket.



I installed all of the electrical wiring and components to the other side of the box. I used epoxy to attach a terminal block to the bottom of the enclosure to make all of my connections. The switch on the right powers up the system. The one on the left was installed between the PID controller and the fan. I use it to keep the fan from coming on when I raise the lid to baste or turn meat. I cut a hole in the lid with my Dremel to slide the PID controller in and applied silicone around the edges to keep out water. Also applied some to the base of the switches. I wired up the PID controller and it was good to go!



I've only tested it with a heat gun as of yet, but it works as designed. The good thing about the PID controller is that it is an intelligent controller. It has an autotune feature that helps it learn how the fan output affects the temperature and adjust accordingly.

I'll be testing it out next weekend (if I can wait that long). I'll be looking forward to sharing my results!

Happy fourth!

So, how well does it work? I have been looking for a build like this.

Scott,

It works very, very well. I used it in simple on/off mode this weekend to smoke some baby backs. I set it to come on when the temp gets three degrees below the setpoint. It powers up the fan, raises the temp back to the setpoint, then powers off the fan.

I'm gonna be very comfortable smoking some pork butts overnight with this thing attached.

One thing i've found though, the thermocouple mounted to the side of the smoker picks up heat from the body and thus causes the temp reading to be about 15-20 degrees higher than my et-73. I tested them both in boiling water and they read 210 and 211. I've decided to either get a silicone, high heat grommet to keep the thermocouple from contacting the body of the smoker, or switch to a different thermocouple like the one that comes with the et-73.

I saw that Auber also has a controller specifically for controlling a charcoal smoker that comes with pretty much everything except the fan and mounting options or an enclosure for $75. Smoker Temp Controller I pondered purchasing it, but since I had most of the other parts, I purchased the PID controller and TC only.

They also offer PID controllers with dual displays so you could monitor meat temp as well. I didn't need that because I use my et-73 for the meat.

Also, I'll be drilling a "weep hole" in the low point of the outlet pipe to the smoker. I got an inch of rain in about 20 minutes and the rain got in the smoker and then travelled through the outlet into my controller. Didn't hurt anything since it's 12 volts but I don't like the idea of water inside and it eventually could cause problems.

Also, I spoke with Auber regarding the face of the PID controller and inquired if it was waterproof. He told me it was waterproof and that I just needed to use silicone around the edge where it meets my enclosure. **Unfortunately, this is not true** Water got through the face of the controller and it went wacky. I dried it out with a heat gun and it started working fine again. Looks like I'll be caulking around the face where it meets the rest of the controller and I might even create a lid for the whole thing out of a clear tupperware tub or something.

I'll try and keep you updated on the rest of my modifications.

The idea of cutting up a junction box to use as the enclosure is brilliant. The only think I might change is the use of flexible conduit to make it easier to move around.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dchristensen:
The idea of cutting up a junction box to use as the enclosure is brilliant. The only think I might change is the use of flexible conduit to make it easier to move around. </div></BLOCKQUOTE>

I considered buying some flex but had the rigid conduit scraps laying around. I might switch the outlet pipe out with some flex if I end up with a piece in the future. I sure wouldn't have had to be so careful about bending the conduit to just the right angle if I had flex.

I made some small modifications to my controller yesterday. I added a plug on the exterior of the enclosure for the thermocouple and now will be able to disconnect the TC instead of detaching it from the WSM body. New TC is similar to the one from my et-73 as it does not attach to the smoker.



I also moved the power connector to the same end as the TC plug so I could run them both out of the rain lid I made. The lid will only be used when it is going to be raining. The enclosure itself keeps most of the water out but I don't want to get the PID controller wet and have problems again.



The tub was just the right size as I can still put the tub lid on and use it as the bottom when transporting the entire unit.



I'll also be working on a DIY probe tree that I'll post on later.

I like the way is looking, are there any updates?

Hey Mac,

Nothing new on the controller. I've just been using the HECK out of it. The thing works pretty good. I've done a couple of overnight butt cooks and an overnight brisket. 14+ hours on the brisket. No problems. Been gettin' some good zzz's while that thing is connected to my WSM.

Also smoked ribs a couple of times using the controller. I'm glad I installed the second switch to kill the fan when I raise the lid. I forgot to turn it off one time when I raised the lid to move things around and lets just say the controller didn't have to stoke the fire for a while....

One thing I have done is I molded a probe tree out of some high temp silicone. I'll post some pics as soon as I can snap em'.

After using the controller about ten times, I haven't come up with any mods that are necessary. I'll keep thinking though. Let me know if anyone has any suggestions.

Aaron

looks interesting. How in the world do you attached the 1" conduit into your WSM?

NM! I scrolled over in the picture! I designed a PLC and touch screen program to control a smoker for a friend of mine that does competition BBQ, but it is more expensive then the stoker and guru, and does not have web capability. The touch screen is much more user friendly though and the programs can be easily modified since I wrote them myself. I could easily make it web capable, but that would add alot more cost to the system because it would require a touch screen with a web interface built in and those cost around $600.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ACrocker:
Hey Mac,
...
One thing I have done is I molded a probe tree out of some high temp silicone. I'll post some pics as soon as I can snap em'.

Aaron </div></BLOCKQUOTE>

Any update on the probe holder?

Todd

Aaron,

If you sold this I would buy it. The only question I would have is the fan. If it goes out is it easy to replace and will the PID recognize it?

Richard

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Todd E.:

Any update on the probe holder?

Todd </div></BLOCKQUOTE>

Check this post for info on the probe holder I made.

Probe Holder

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Richard Diaz:
Aaron,

If you sold this I would buy it. The only question I would have is the fan. If it goes out is it easy to replace and will the PID recognize it?

Richard </div></BLOCKQUOTE>

To answer your first question:

The fan is a standard pc cooling fan. CFM's vary greatly between different brands and models but if it ever went out, it could be replaced for under $10. These fans are put into pc's that may run 24/7 and most are rated for 100,000 hours or more so I doubt it'll quit. I use my Maverick ET-73 to keep an eye on it though.

To answer your second question:

There would be no problems with the PID controller recognizing the new fan because the PID controller does not know what it is controlling. It simply opens a switch that allows the fan to turn on when the process value (actual temp) drops a certain amount (hysterisys or dead band) below the set point (desired temp).

I have a three degree "dead band" programmed into mine. Let me give you a scenario, If the set point (desired smoker temp) is 225, and the smoker temperature (process value) drops to 222, the PID controller kicks on the fan until the temp gets back to 225. So the dead band is the area below 225 but above 222.

The purpose of this is so the fan doesn't kick on and off in a short amount of time. If the dead band was larger, say ten degrees, the fan wouldn't kick on until the smoker temperature (process value) dropped to 215. Then the fan would have to run longer to get back to 225, the coals would be stoked too much, and the temp would rise way over your set point of 225.

I hope all of that makes sense.

Acrocker,
This looks great. Love the DIY stuff.
Have you used this in high heat cook?
I'm wondering if it could maintain 350 deg?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Glen Detlefsen:
Acrocker,
This looks great. Love the DIY stuff.
Have you used this in high heat cook?
I'm wondering if it could maintain 350 deg? </div></BLOCKQUOTE>

Glen,

I have used it to assist in a high heat cook once. I still opened the other two vents to get it up to temp though. I haven't attempted a high heat cook with the other vents closed though.

I don't know if it would maintain that high of a temp with the other vents closed. I didn't find out mainly because I wasn't patient enough.

I really haven't found it necessary to use the temp controller in a H.H. cook since they are only for a couple of hours or less.

I am planning on trying a H.H. brisket though, so i'll let you know when I try that. Should be interesting.

If it doesn't keep up, I can always upgrade to a higher CFM fan.

Very cool project! I'm in the process of putting one of these together from mostly scraps as you have done. Can you post a link to the pid you used? Did you need a separate ssr for it as well?

Also, which TC did you finally end up using (link?)?

Thanks!

Neil

Neil, it looks like it's this model:

http://www.auberins.com/index....ath=1&products_id=14

Maybe AJ can confirm it.

Thanks for the reply Jeff -

After going back to their site and downloading the manual I figured out which model AJ was referencing. The one you linked to is an AC version, below is the 12v DC version:

http://www.auberins.com/index....ath=1&products_id=83

Based upon the circuit of the 12v one in the manual, you don't need the ssr (relay) to drive a 12v fan.

For the Thermocouple, AJ must be referring to either one of these:
http://www.auberins.com/index....th=3&products_id=173

or this one w/ the alligator clip:
http://www.auberins.com/index....th=3&products_id=172

And the panel mount connector:
http://www.auberins.com/index....th=3&products_id=119

Thanks for the help, Jeff, and to AJ for the initial design!

Neil

Please keep in mind that without the ssr you run the risk of wiring and connections burning up or causing it to short out the pid. The ssr helps regulate the flow of electricity to the fan. The ssr will give the pid a longer useful life. The plug n play unit that they sell I believe the syl-1613 has a ssr built in, if they do you should probably do it to. I would suggest sending an email to Suyi with Auber to give more depth to the topic. Just go to their website and send an email via their contact page. He will get back with you quickly, they provide excellent customer service.