May I suggest you look at some of the 'blinky LED' projects listed at this site:
http://www.kpsec.freeuk.com/proj.htm
If you want to learn more about how to create the projects, there is a link at the bottom of that page that says "Study Electronics". Click on that and proceed page by page though the instructions. Should only take a little while. If you come to a page that does not interest you, just skip it for now. You can always go back and review it later. When you're done, you'll fully understand the information listed for each project. With a little work you can modify these projects for your robot.
If you're looking for the parts, let me know. I can recommend a good place to get these things in the USA that won't cost too much.
Regards,
KHall