Author Topic: DIY PID controller  (Read 1708 times)

Offline Malc C

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DIY PID controller
« on: October 03, 2012, 04:50:03 am »
I've had my Bradley smoker for around 4 months now and still experimenting with cooking times etc for different meats.  I noticed that there are an active bunch of modders here who have changed or doubled the heating elements, added fans or even PID controllers to their smokers and this got me thinking.

A few years back I developed a four channel thermostat / lighting controller for my reptiles.  This uses a digital temp sensor and a PID routine to determine the pulse length to be sent to the heater to maintain the desired temperature.



I was contemplating re-compiling the code for a single channel unit for use with the Bradley, however my main concern is the use of the digital probe rather than a thermocouple in the environment.  Whilst it can handle the temperature range, its the affect the smoke etc would have on it, and thus would welcome comments.

Offline muebe

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Re: DIY PID controller
« Reply #1 on: October 03, 2012, 05:19:22 am »
I am not familiar with what a digital probe can handle. Keep in mind that there is also a lot of moisture in the cabinet along with the smoke and heat.

I suggest your plans use an RTD or Thermocouple type sensor because we do know those will and do work. And they are pretty inexpensive to purchase and replace.
Natural Gas 4 burner stainless RED with auto-clean
2 TBEs(1 natural gas & 1 LP gas)
OBS(Auberins dual probe PID, 900w finned element & convection fan mods)
2011 Memphis Select Pellet Smoker
BBQ Grillware vertical smoker(oven thermostat installed & converted to natural gas)

Offline Malc C

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Re: DIY PID controller
« Reply #2 on: October 03, 2012, 08:06:39 am »
Thanks for the comments.  The DS1307 one wire digital sensor is quite cheap, and because it's digital makes coding a lot simpler as there is no need to use AtoD conversion of the output volatage coming from a thermocouple, but that's not to say it's not possible, just that the resolution would need some working out.

Offline KyNola

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Re: DIY PID controller
« Reply #3 on: October 03, 2012, 01:39:23 pm »
Thanks for the comments.  The DS1307 one wire digital sensor is quite cheap, and because it's digital makes coding a lot simpler as there is no need to use AtoD conversion of the output volatage coming from a thermocouple, but that's not to say it's not possible, just that the resolution would need some working out.
That's just hippie talk! ;D