MAKE your own controller

[Static]

http://www.parallax.com/

I played with The basic stamps for a while. I could make buttons flash LED's and stuff, but the hard part came when I had to try selecting transistors and relays to turn the 5v at low current into something useable.

It looks like that make controller actually ouputs a bit more current,and might be more useable. Maybe even just to log temperatures and stuff on your computer. How would you go about making it switch a relay to turn a heater on/off?

If you go anywhere with this project please post cause I'd really like to learn how you do this