A brushbot is a circuit with a vibrating motor on top of a brush such as a nailbrush or toothbrush.
The kits are a bit pricey ($15-20), so I decided to make my own using a nailbrush, a battery holder, a switch, and a motor. I had the motors from another project but had gotten them for about $1.00 each, the battery holder was $2.00, the nailbrush, $1.00 from Target and the switch was $3.50 at Radioshack. So the total cost for my brushbot was $7.50. It could have been cheaper if I had bought the components in bulk from internet supply stores, but I had only 4 kids in the class, so Radioshack was convenient.
Above are three of the bots built by the fourth and fifth graders. They had a great time building them and felt a real sense of accomplishment when we got them all up and running.
Here is another photo. The main problem we had was getting the kids to make a good connection to the various components with the wires and then taping them with electrical tape. For some of the kids, it was a bit challenging. But, after a few tries, most of them got pretty adept at wiring. The other problem we ran into was balancing the bots so they vibrated without falling over. That task involved moving the components around on top of the brushes until we got them balanced. I used balanced motors, so to get the motors unbalanced to allow them to vibrate we attached alligator clips. Today, the kids will finish making there vibrating bugs. I will show photos of those next week.