Saw instructions for a giant bristlebot in this morning’s Instructables newsletter and immediately knew I wanted to build one with Miles. Then realized the smaller versions – based on a simple toothbrush head – were even more do-able. Decided on this improved version with antennae to help it resist falls and to bounce off walls and objects.


Parts needed:

  • Toothbrush head – with flat, not curved bristles
  • Button cell battery
  • Small vibrating motor from a pager or cellphone
  • Double-sided adhesive foam tape
  • Nails
  • Possibly a soldering iron

Radio Shack, unfortunately, doesn’t stock vibrating motors. Nor will they give you old/returned cell phones to pull apart to pull the vibrators out of – they’re all in a database, destined no doubt for China where they’ll be pulled apart by underpaid workers in toxic waste dumps. They did, however, give us a couple of flat batteries with a bit of charge left in them. Headed for MetroPCS to see if they’d give us an old phone to tear apart. Nope, same story. But a guy in line heard us, and offered to sell us his old one for $5. Bingo!

We were able to pull the vibrating motor out just in a few minutes. But it had no leads – I was going to have to solder some onto the two bare contacts. Hacksaw and sandpaper worked perfectly on the toothbrush head. Everything came together pretty easily per the Instructables instructions. We were amazed – our bristlebot worked WAY better than expected! Totally scoots along. Turns out the key to getting it to go straight and not in circles is to really bend those bristles back, so that they store and release energy in a forward direction.


Unfortunately, not everything went exactly to plan. I plugged in the soldering iron to warm up on a high-ish shelf while Miles was in another room playing with the cell phone leftovers. I went to the garage for a couple of minutes, then heard him crying loudly — he had wandered in, seen the electrical cord, gotten curious, and picked it up just to see what it was. Got burned pretty badly on his thumb and forefinger. Long period of tears, ice, ibuprofen, burn cream, and of course, ice cream. And of me feeling like a total bad dad for not warning him about it. I assumed he wouldn’t be in that room, and assumed he wouldn’t see if it he did come in. And got bitten by my assumptions. Felt horrible for the little guy. He’s doing OK, and we had a gas playing with the bristlebot at the dinner table.

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