March 4, 2011

Bristle Bot

      Bristle Bots are a simple device that translate the vibrating motion of a pager motor into foreword momentum. As the motor vibrates its kinetic energy first pushes the bot down and then pulls it up. As the bot is pushed down the bristles work like a spring compressing. Then as the vibrations pick up on the brush the bristles decompress if your brush has most of the bristles angled in one direction this pushes the bot in the opposite direction.
      I started looking into steering these devices and found that by shifting weight over the device you can change its center of gravity and make it tern. The problem with this steering system is that it requires a fairly wide platform. The bots that use this principle are made with two bristle pontoons with the vibrator and weight  in the middle. This seemed to  make it hard to scale down the steerable bots. Because most of the fun of these bots is there size i wanted a design that I could scale to any size so I started trying different steering methods. This is the result.

 I wanted my bot to only have one brush so I decided 
to force the bristles into changing angles to steer the bot.
Sending current into the motor causes one paddle
to compress the bristles and the other one to pull away
from them. Switching the polarity reverses the paddles.

I removed the inner bristles from the steering
section because it increased the sensitivity of the handling.

The Bristle bot steers comparably to other bots I've seen online. I don't have a video camera to show it to you it in action.


  1. Video proof it or it's now working.

  2. While I won't outright say "proof or it's false", I do find it interesting that he can't do video, since as far as I know every digital camera out there has simple video capabilities built in for short clips....

  3. Its also extremley boring without a video

  4. Even if it doesn't work, it should work.
    Good advice for other, we are close to Bristle Bot commandos.

  5. Awesome!
    What kind of battery is that?

  6. Video would be nice.

  7. @ Moldboy
    Its a cellphone battery pack the mettle case slides back and then picks up so the battery can be removed and charged in the phone.

    @ almost everyone else
    I'm sorry I'm broke and can't get a new camera and am stuck using my dads ancient suckie one if you want to see it working feel free to email me to set up a meeting.

  8. Do you have a list of parts?

  9. Parts List:
    something withs bristles at a slight angle
    1 dc motor
    1 dc motor with offset weight
    4 1/4" sheet metal screws
    cellphone battery
    sheet metal (any gage semi-rigid will work)
    one small bolt and matching nut
    wire assorted gages

    I will make some detailed schematics and add a link to them at the bottom of the post in a couple of days.

  10. The schematics are proving difficult to make. I'll try to get them up today.