Scripts and scraps from my real-life parenting sitcom.

BRISTLEBOTS: original video from

Last year, Luke (age 6 at the time) was getting really interested in the little Hexbug Nano toys, as well as Legend of Nara Battle Bugs, which are basically the same thing but with a rubber bug stuck on top.  These are pretty simple machines: they use a vibrating motor (like in a pager or cell phone) and angled rubber legs to move the toy across a hard surface.  They are kinda cool, I admit.

I stumbled across the Evil Mad Scientist instructions for something called a “bristlebot”: a do-it-yourself vibrating “bug” made out of a toothbrush head, pager motor, and battery.  It looked pretty simple, and I thought Luke would find it interesting.  Then I realized a lot of other people were making variations on this, and some enterprising small businesses — like Brown Dog Gadgets — offered kits with all the parts to make these things.  So we ordered a kit or two from Brown Dog Gadgets.  (Incidentally, Joshua, the guy running Brown Dog Gadgets, is really helpful and thoughtful and knows his stuff. He’s a science teacher too! Yes, this is free advertising from a satisfied customer.)

After putting it together, I realized a couple of things:

  • Luke’s 7th birthday was coming up, and it would be cool to have a bristlebot-building party for a group of 7- and 8-year-old kids.
  • I wanted an on/off switch on the thing.  Simply connecting and disconnecting the battery was annoying.

So we ordered a big supply of parts from Brown Dog — with a custom order that included switches and bigger batteries — and we experimented.  I had to engineer my own assembly process because I wanted a method of building the circuit that could use prepared parts and, even with the switch, didn’t involve soldering or tying small wires together.  (I’m willing to teach soldering to my 7-year-old, but not to a group of 7-year-olds.)  Then my wife came up with the idea for attaching a decorated plastic egg, which Luke loved.  And so it came to pass: we had a bristlebot birthday party, with me and my wife teaching a group of kids, step by step, how to build one of these little things.  They had a blast. I didn’t try to turn it into a science lesson, even though they were basically building very small circuits to run a machine.  It was just building a neat little toy.  I heard from one of the kids’ parents recently that the little bristlebot was still working, more than six months later. 

Unfortunately I have no pictures or video from the party itself because I dropped my camera and broke it ten minutes before the party.  I had another camera but it wasn’t charged.  So, much later, we took a video of the assembly process, and I finally got around to editing it down to one minute of video.  (Why one minute? That seems to be what I’m aiming for with the And I’m The Dad original videos, aside from the OWS video.) 

You get an extra ten points if you recognize the soundtrack.  I’ve named it in the footnote here. 

Anyway, below are the instructions.  Try it out yourself, and make it your own way.  If you do something with it, please e-mail me or write me a note because I’d like to know.

These steps will make more sense with the video.  Regardless, you should read through it all the way and prepare whatever pieces you need — and most importantly, experiment to see what works for you.  And feel free to ask me any questions via ask or e-mail.


  • 1” foam doublestick tape
  • 2 toothbrush heads, attached with tape (see video)
  • 1 vibrating pager motor (with wire ends bent)
  • 1 battery (I’m using a 3V CR2032)
  • 1 switch (with one prong bent or angled up, one bent down)


  • 1 round cutout of hard craft foam
  • 1 6” string with a knot tied at one end
  • 1 longer half of a plastic egg (I guess it’s not really “half” if it’s longer, but you know what I mean)
  • Assorted craft items: pipe cleaners, eyeballs, paint, stickers, blood, etc.


  1. If you haven’t already, attach the toothbrush heads side by side on a 1” square of the foam doublestick tape.  Take off the tape paper to expose the top sticky side of the tape.
  2. Place the motor on top of the tape, parallel with one of the toothbrush heads, so its spinning head hangs off the edge.
  3. Position the wires to the motor so one is flat on the tape (stuck to it) while the other is upward and free.  We’ll call this the lower wire and upper wire.
  4. Place the battery on the tape, across both toothbrush heads, making sure that at least part of the bottom of the battery is resting on top of the end of the lower wire. I bent the end of that wire to make sure it tipped upward a little, trying to ensure contact.
  5. Place the switch next to the battery. One prong should be bent or angled down to directly touch the battery.
  6. Stick a smaller rectangle of the tape on top of the battery, sliding one edge between the two prongs.  Remove the upper paper on this tape.
  7. Attach the upper wire to the upper prong, on top of the tape from step 6.
  8. Stick another piece of tape on top of the one from step 6, on top of the wire and prong from step 7.

    — Steps 9-12 are only needed if you’re putting the wacky decorations on top of this thing —

  9. Stick a smaller strip of tape on top of the switch. Peel off the top paper from this tape and the tape from step 8.
  10. You should have already prepped the piece of craft foam to fit on top of this.  To make it the size of the plastic egg, press the egg half straight down through the foam.  Then use a knife to trim one side of the bottom so it’s two levels, to fit across the sticky tape from steps 8 and 9.  Anyway, press it in place.
  11. If your switch has a hole in the side of it (as mine do, normally for screws to hold it to something) then pass the string through it up to the knotted end.  This will act as either a leash or a tail.
  12. Decorate your plastic egg half so it looks… uh… like whatever you want it to look like.  Robots?  Monsters?  Dolly Parton?  Whatever floats your boat.  Once decorated, slide it down over the craft foam.  Turn on the switch, and there you go.

Tip: the bristlebot is less likely to turn in circles if both sets of toothbrush bristles are pointed straight down.  Better yet, if you can find toothbrushes with angled brushes, make sure they’re all pointing in the same direction, and the bristlebot will move in a direction.

Original video is ©

The soundtrack music is from the 1986 movie “Short Circuit,” from TriStar Pictures (part of Sony Pictures).  It is used here without permission, but with sincere affection and nostalgia, for whatever that’s worth. Number Five is alive!

  1. andimthedad posted this
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