You don't need a powerful microcomputer to drive this setup. We selected the Arduino for this project because of the excellent (and well documented) PID and autotune libraries available for it. The Adafruit RGB/LCD shield with integral pushbuttons was also perfect for hosting the user interface.
To build this controller, you will need:
We have all the above as part of a special discounted pack http://www.adafruit.com/products/1401
You will also need some basic tools and soldering supplies:
- WIre cutters
- Wire strippers
- Soldering Iron
- Shrink Wrap Tubing
- Small Phillips Screwdriver
Rice Cookers and Slow Cooker appliances have the basic elements we are looking for:
- A cooking vessel that holds water
- An electric heating element
You need a vessel substantially larger than the food you intend to cook in it. It needs to have a large enough volume of water with plenty of room for circulation to maintain an even temperature. Look for a rice cooker with a capacity of at least
10 cups uncooked (20 cups cooked) or a slow cooker with at least
a 4 quart (4 liter) capacity.
Since we are building our own controller, you want the simplest manual control cooker you can find. One with a simple switch or control knob is best. We will just turn it on at the highest setting and plug it into our controller. (Here at Adafruit we picked up a "Black and Decker RC880" - a rice cooker with 24 cup capacity and is a great size)
Cookers with digital controls are not suitable - unless you want to rip them apart to bypass the electronics. The controller works by pulsing the power to the cooker. If you do that with a digitally controlled cooker, it will just turn off!