Design for ColdFusion Temp Controller with Relay

[KosherSmokin]

Thanks guys for all your encouragement.

Yeah, I agree with Tom, the main reason I have apprehension to building them is the liability involved (including but not limited to burning my customer's house down ^_^).
A relay, mounting and schematic kit wouldn't be a bad idea though!

I would agree that it's not that difficult a design if you've ever done some electronics before.  Just triple-check your connections before you plug it in.  Even if you're not confident, if you have an electrician friend you trust, it's really not that hard to put together if you give him/her the schematic.

I'd be happy to post where I got all my stuff or make a mounting diagram (yes, with the top on). I sort of innovated my own female power jack from a plug by drilling a larger hole through it and pushing a bolt through.  I could do the male one the same way if I wanted to.

A normal outlet will work too.  But Tom's extension cord cut in half is easier though.



<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">If heat becomes a problem inside the box I might consider some kind of insulation around the relay.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">In general if you're having any heat issues I don't recommend it.
Remember a heatsink is there to conduct the heat away, not build it up.  If the current vent config isn't doing the job, insulation will definitely NOT solve the issue.

Incidentally, it turns out my bullet water-smoker has a big hunk element rated at 1800W (about 15A)!
That explains my heat issues (~160F).  If I were going to continue to use my bullet with the controller, I'd probably either put a heatsink on, get a higher rated relay (like your 40A), or both!  

With the Bradley's 5A, I guess you're not having this issue and the air vent's doing the job.

However, I'm definitely staying with an all-aluminum design so the heat doesn't build up over a long, possibly overnight smoke.  To me it's worth the extra $10.  YES I'll put a top on too! LOL

Have you done overnighters with yours, Tom?  I'll hopefully have enough confidence in mine to do an overnight pulled por~...umm...beef...err...shoulder [:D] in my Bradley without any worries.

Thanks again,
-Sam

[rgardjr]

Well I finally had a chance to add up the cost of building the PID and it was a little more expensive than I intially thought.  When I ordered parts I got 2 of everything except the PID so I could build another one in the futre.  A quick run down of the cost including shipping:

PID Controller of Ebay $49.00
Digikey parts (Enclosure, plug jacks, fuse holder, fuse, power cables) $28.85
Radio Shack (Terminal Strip)  $5.74
Ace Hardware Misc 16 guage wire & 2 aluminum spacers for SSR $3.00
SSR Relays 10 Amp from Ebay (3 for $20.77) $6.92
Omega Thermocouple panel jacks, plugs, wire $19.90
Thermocouple from Bill(Coldfusion included was garbage) $7.65
Plus misc wire connectors that I already had ....

Running total of <b>$121.06</b>

I know that it can be done cheaper, but I really wanted it to beable to just plug the smoker into it an not have to mess around with the thermocouple every time.  I included a 10 amp fuse as a safety feature and the cables that are used have plugs that make them idiot proof.  So if any body wants help putting one together I will certainly provide part numbers, wiring diagrams, ect ... as well

[IKnowWood]

This is all a bunch of good technical information.

i got a simpe one, has anyone talked to ChezBubba about marketing a good reliable Mod for those of us that do not have the technical expertise nor time to build something like this?


The Medina's in Maryland's Eastern Shore

[TomG]

My cost and sources were almost the same as rgardirs' with the exception of a project box from RadioShack for $5.40 and an air condioner ext. cord from Ace for $7.45 for a total of $92.00. I used a Dremel saw to cut holes in the plastic box and grommets and heatshrink tube from HomeDepot to dress up the power cords.

Right now I'm playing with a $32 PID from http://www.kelinginc.net/ which can be user programed for nearly any type of thermocouple and either F* or C* temp units for our Northern Commonwealth brothers in smoke. It will need a thermocouple which can be purchased from Bill Kulas for $7-12.

Sam, as far as isolating the SSR with insulation within the box, my concern was to minimize heating the PID above its specs max operating temp of 122*.  Apparently the SSR is good to go up to 175*.  I used the ext. cords for I/O to keep box contents to a minimum. If their length became a problem I would just cut them shorter so only an inch or two extended outside the box. And no, I haven't had a chance to do a BS overnighter.

Cheers-Tom-