I picked up a nice little PID from a site in China for cheap, at about 35 bucks.
I use mine to control a small draft fan, a 32 CFM, 110VAC muffin fan that I had in my junk box, so I used a small SSR that I already had in my junk box too but they sell SSRs for cheap too if you need one of those for your setup.
The PID takes just about anything for power no matter where you are, either AC or DC as a matter of fact. It has an output for controlling a SSR (Solid State Relay), about 10 volts DC. The SSR which is used to control the temperature control device whether it's a fan or a heater element. I has a separate relay output for an alarm which can be programmed as either an over or under temp alarm. I use a red light bulb as an under temp alarm to warn me if my temp is getting too low and I need to add some fuel.
It has a self tuning feature if you need to use the PID type control and don't feel up to PID programming. I've set mine up for simple on-off control as I am only using it to control a stoker fan to control the lump/chunk fire I use for smoking.
The bottom line is that it's cheap, small and versatile.
I got this temp sensor from the same outfit which is a platinum type instead of a regular K type thermocouple. It has a stainless steel housing. For 5 bucks, why not? It actually uses a thin film on ceramic substrate sensing element using platinum as the temp sensor. I drilled a hole in the smoke chamber and mounted it in the smoker so it sets just below the level of the grill. I usually cover is with a piece of aluminum foil to keep it from getting all greasy from drippings.
Temp Sensor http://www.virtualvillage.com/thermo...03820-034.html
This SSR should do the job for just about anything, even the heating elements for you electric smoker fans out there. It will handle up to 40A at 220VAC which is more than any of you probably run in a smoker. That's 8.8KW or almost 9 thousand watts, folks. Another 5 bucks or so.http://www.virtualvillage.com/40a-ss...03602-009.html
If anyone needs help with how to wire one up, let me know. I'd be happy to give you some pointers. I'm a retired EE type. The instructions can be confusing to some because of the poorly written documentation but I can help out there too if need be. Not griping their English is much better than my Chinese.
So far so good. It keeps the temp just where it needs to be and just right. I have it set for a 3 degree swing but can be either tighter or wider as you may want.