Step 1: Here's what you need...
Like I said, this doesn't get much easier and it's cheap.
1 - CD or DVD. This is something you can make with those old scratched up discs.
1 - Dollar Store vibrating toothbrush.
1 - Package of Markers.
1 - Hot glue
You will also need a drill and drill bit to make the holes. The size of drill bit depends on the diameter of the markers. The markers that I used are 3/8" in diameter
Step 2: Drill and Glue
If you couldn't tell from the intro, this is going to be so simple.
1> You need to measure the diameter of your markers. The ones that I used are slightly tapered, so a 3/8" drill worked perfectly.
2> Drill a series of at least 3 holes in your CD. I recommend having a wood block under the CD as you drill. The hole stays cleaner, and is less likely to break the disk. As you can see I did one with 3 holes, and another with 8 holes. Why the difference? That is what makes DoodleBot360 so much fun. You can experiment with different hole configurations to see what happens. (Note: I found that I could not get it to move much with 8 markers and 1 motor. I might try 8 markers and 2 motors)
3> Remove the toothbrush head, install batteries, and then hot glue the base to the CD. Becareful not to glue the battery holder down, so you can change the battery when it goes dead.