Our September Engineering Challenge was a bit of a departure from our previous challenges. Usually I try to keep the Engineering Challenge programs very open ended. I declare a goal, and then give the children supplies to achieve that goal in whatever manner they can think of. The Brushbots were much more “follow the directions” for the first half of the program, with creativity coming once the brushbot had been assembled and we were ready to decorate our creations. However, I thought that making little vibrating creatures was too appealing to pass up.
To make the brushbots I followed instructions found here, with the addition that we used two toothbrush heads instead of just one. One of the many websites about brushbots that I had looked at suggested that double heads made for more stable ‘bots, and a quick experiment convinced me that this was true. Basically we cut the heads off of cheap toothbrushes, then used double sided mounting tape to both hold the two brush heads together and to create a sticky surface upon which to place the vibrating motor from a cell phone (available for about 75 cents on amazon). I had peeled the plastic back from the wires on the motor ahead of time, because I was worried that the students would snap the wires. On top of the exposed wire, we placed a coin battery. Since the wire was extending over the mounting tape, the coin battery just stuck to the tape. To make the creation vibrate, all we had to do was use a piece of clear tape to press the second wire onto the top of the battery. Peeling the tape off stopped the vibrating, creating a very simple on/off switch.
Next was the fun part: decorating the brushbots. I did not get very many pictures, for a variety of reasons, and the ones I did manage to take are mostly blurry, but there was a lot of creativity on display. I had set out all the decorative elements I could find from my craft closet, including beads, pipe cleaners, tissue paper, plastic eggshells, tissue paper, googly eyes, and more. As a special added touch, I had a number of flashing LED diodes that were leftover from a previous project. Since we were already using batteries for the motors it was easy enough to attach the diodes to the battery. They were, not surprisingly, a big hit, with some brushbots sporting multiple batteries to accommodate the number of flashing lights.