Digital temperature control for smoker
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Category: Saltwater Fishing
Forum Name: The Kitchen - Seafood Recipes
Forum Description: Share your favourite seafood recipes here
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=66760
Printed Date: 10 Jun 2026 at 10:41pm
Topic: Digital temperature control for smoker
Posted By: JackDalton
Subject: Digital temperature control for smoker
Date Posted: 06 Jun 2011 at 12:49pm
 So ive had smoker envy (Bradley envy) for a while now, every time I smoke some fish in my homemade smoker I dream about being able to set it and forget it. However with my current set up I dont feel confident that the smoker will behave itself if I left it to its own devices. Currently I use an electric element at the base of a 44gallon drum with a stainless steel dishwasher perched on top. A lump of wood sits on this element which provides both the heat and the smoke (smoker described with more detail in http://www.fishing.net.nz/asp_forums/home-made-smoker_topic15875_page2.html) However occasionally the wood will catch fire or if the day is cold the smoker wont be hot enough etc etc which requires a bit of tinkering with the elements setting and wood etc to get "just right". So I have decided its finally time to install a digital control for the temperature of my smoker and the smoke will be produced independently via a DIY smoke generator (not built yet but based on the awesomely helpful thread http://www.fishing.net.nz/asp_forums/diy-smoke-generator_topic62918.html) Rather than going down the thermostat route I wanted something a bit more sophisticated for my control unit so began investigating PID controllers, which offer much improved control over temperature etc. I picked up most of this stuff from ebay pretty cheap. However I did purchase the incorrect PID controller which needed some minor "modifications" to suit my needs. My PID controller is a REX-C100 unit (think this is a Chinese knock off job): http://cgi.ebay.com/New-Dual-Digital-F-C-PID-Temperature-Controller-Control-/280574783198?pt=BI_Electrical_Equipment_Tools&hash=item41538f6ede This one has a relay output which is not what I needed - I needed one with a voltage pulse output to drive an external solid state relay (SSR). Ah well - it was a minor effort to "fix" this - as I will describe later on for those that are interested. The solid state relay (SSR) was likewise purchased from ebay - these are much better than mechanical relays as they have much longer life times. http://cgi.ebay.com/25A-SSR-SOLID-STATE-RELAY-3-32VDC-24-380VAC-/260794884074?pt=LH_DefaultDomain_0&hash=item3cb8961fea The general idea is that the PID controller will sample the temperature and control the SSR which in turn is connected to the heating element in my smoker. Pretty straight forward. But why stop there? - Instead of integrating the whole thing into my smoker permanently I decided to build a stand alone PID controller that could be detachable and able to control a variety of processes (like keeping my bedroom at a nice 24 degrees by attaching it to my heater during winter for example) So I purchased two panel mount mains sockets from Jaycar (the input one is fused) and some banana plugs for interchanging temperature probes and set about installing them into an aluminum project box (also available from Jaycar)  The input mains socket provides 240V to the PID input and also attaches to the output socket via the SSR (which switches live on or off) Only the Live wire is switched by the SSR - the earth and neutral wires connect directly to the output socket. The Temperature probe is attached to the front of the unit via banana plug sockets which allow quick swapping of probes. The PID delivers a voltage pulse of +12V DC to the SSR control terminals which activates/deactivates the Live connection to the output socket.   The whole thing is earthed and fused so if something does come un-stuck inside this aluminum housing it will ground out and blow the input fuse. As stated above, the PID controller I brought was the wrong type and needed some minor modifications - Basically it has (had) an internal mechanical relay that would switch 240V AC PID connections were such that it was expecting the Live terminal for the output socket to be connected directly to the PID controller. I simply took the internal relay out and jumpered the drive voltage of this mechanical relay to the output connections on the PID controller. As shown below:  Find output Relay - de-solder and attach jumpers from the Relay control to the Relay Output - now you can run a SSR - yay.  I will update once my element is installed in the smoker - Im going to remove the 44 gallon drum and just use the dishwasher body as that will be less internal volume to heat. Cheers. |
Replies:
Posted By: H8_4DS
Date Posted: 06 Jun 2011 at 8:47pm
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I have a temp controller and temp probe somewhere in my garage, if my memory serves me right. Will have to see if i can find it and see if it still works. Looks very similar to your one. ------------- Formally Known as nvmyvl |
Posted By: H8_4DS
Date Posted: 07 Jun 2011 at 10:16am
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Just found it. its a Shinka JCS temperature controller.
Will post picks up later on tonight. just have to work out how to control the small element that i have off of it. Im no good at the 240 volt wiring stuff hahaha ------------- Formally Known as nvmyvl |
Posted By: Haydan
Date Posted: 07 Jun 2011 at 11:00am
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Great Idea! Shouldn't the SSR have a big heat sink on it? |
Posted By: JackDalton
Date Posted: 07 Jun 2011 at 1:15pm
| Yeah - thats why I chose the aluminium box - so the whole thing acts as the heatsink. |
Posted By: Haydan
Date Posted: 02 Aug 2011 at 6:49pm
| How did this all work out for you in the end? Just building a smoker now and am looking at heating options I like this idea. Where did you get your thermal probe from? |
Posted By: studio1
Date Posted: 19 Aug 2011 at 10:00pm
| this is awesome - thanks - I'm looking to build a little pid temp controller like this for my nano-brewery - like the idea of having it work for smoking and other stuff too.. |
Posted By: River
Date Posted: 01 Aug 2014 at 12:58pm
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Great Posting - found it after I acquired the same PID. What size box did you get from Jaycar? Cheers |
Posted By: SNOWKIWI
Date Posted: 03 Aug 2014 at 7:07pm
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Jack, You might find that a three term controller is a bit of overkill, and you may be over complicating the control on your smoker. Generally Proportional only, or Proportional and Integral (or reset) should be any amount of control for a smoker, unless it is of great capacity, and you can finely control the amount of heating or cooling of your system, the Derivative function of your controller should never need to be used! I look forward to seeing how it works out for you and what settings you end up with. ------------- http://www.legasea.co.nz" rel="nofollow">  It is to be observed that 'angling' is the name given to fishing, by people who can't fish. |