Homebrew Temperature Monitor/Controller
Latest News
Version 2 of the controller is done. It's smaller, better,
faster, cheaper, and easier than the original.
The new controller is based on the Arduino board, which can be picked up for about $30. In another cost
saving move, I am now using the probes from the Maverick ET-73 temperature sensor. These are simple
thermisters and all the trouble of dealing with thermocouples is gone.
A wireless internet option is also available for the controller. You can connect to the controller with your
web browser to get information as well as change settings.
I just put this site up real quick - there will be more information soon.
The old version of the controller can still be found here.
Details
The hardware is very small, easy to work with, and modular. The Arduino has a concept of "shields" or stackable
modules that fit one on top of the other. I bought an off the shelf Arduino USB board from SparkFun:

Added a wireless ethernet shield from AsyncLabs on to that:

And build my circuit on an Arduino proto-board:

Plug them all together and you get the final system:

Parts List
The bare minimum would be the arduino, parts from the schematic, probes, and a blower. You could probably build it for around $50 if you
already have the probes. However, the LCD display is practically a requirement, especially if you don't ad the WiShield ethernet shield.
- Arduino Duemilanove - SparkFun $30
- (Optional) WiShield - Async Labs $55
- (Optional) ProtoShield - SparkFun $17
- (Optional) LCD DIsplay - SparkFun $17
- Resistors - 2*22K, 1*1K - Radio Shack $2
- Diode - Radio Shack $1
- Power transistor (IRF-510 family) - Radio Shack $1
- 12V DC blower - DigiKey part #P12902-ND $12
- Maverick ET-73 Probes - use your own, or buy replacements from Maverick Industries
There's actually a schematic this time - and it is quite simple:

Source code for the sketch (it is still rough, but it will get you going) is located here.
Feel free to contact me at
bbqcontroller@gmail.com I will
keep up as best as I can, at least until all the spammers get the address.