We basically followed the instructions provided in the original. A few things of note:
- You can get the pager motor out of an old cell phone. I tried doing that, but I didn't have the right kind of small screw driver, and I found it hard to open up the cell phone. So instead I went to pagermotors.com and bought a few 7mm Namiki pager motors.
- The pager motors I bought come with leads attached, so there was no need for any soldering. You simply place one lead under the battery, with the lead and the battery stuck to the foam tape. We attached a piece of tape to the other lead and stuck it to the top of the battery to start the motor running. The tape at the top worked nicely as a switch: simply pull off the tape to stop the motor.
- Make sure that the back of your toothbrush is smooth. Some of the newer Crest toothbrushes have raised patterns on the back, and the foam tape doesn't stick properly to it.