DIY sytem

I got finished my temp controller setup today.
I am using a PID controller I bought off ebay for $55, it included a thermocouple and relay which is used to control the fan.
The thermocouple is also a bolt type which I can install to replace a grate bolt.

Got the fan from an electronics surplus place.
I got a guy to weld up a little box to fit the fan with a plate which the metal flex hose is tied onto.

So far it looks like it is doing the job,
there are some electrical parameters which can be adjusted to help speed ramp up and also avoid overshooting but I will deal with that another time.

I have another which I installed in my espresso machine to control the temp.

Excuse the quality of the pics, the lighting is a bit off.

Well after using a temp control fan system a few times, I would have to say it doesn't really offer much improvement. In fact its a little more hassle since you have to run power and have things dangling.
It might be nice to have to see the temps on your laptop etc.

I have owned my WSM since early 2003,
I would say that once you pack your basket carefully and if using the minion method, spread out the coals in a nice even layer they will burn down evenly more or less and you should be able to achieve 12+ hour cooks easily without needing a temp control system.

The WSM is simply too good of an engineered piece of equipment, simple as it might look.

.02