Bristlebot: A tiny directional vibrobot

Enterprise

The BristleBot is a simple and tiny robot with an agenda. The ingredients? One toothbrush, a battery, and a pager motor. The result? Serious fun.
(YouTube video here.)

The BristleBot is our take on the popular vibrobot, a simple category of robot that is controlled by a single vibrating (eccentric) motor. Some neat varieties include the mint-tin version as seen in Make Magazine (check the video), and the kid’s art bot: a vibrobot with pens for feet.

Toothbrush   Angled Bristles

The starting point is of course the toothbrush. We need one that has more-or-less uniformly angled bristles. (While it may be possible to take one with straight bristles and bend them to suit, I haven’t tried.) If the bristle length is nonuniform (as it is here), it may take scissors to make the bristles all the same.
Snip   Robot Platform

Cut off the handle of the toothbrush, leaving only a neat little robotics platform.

Pager Motor   Motor & coin cells

Next, we need a vibrating pager motor or other tiny motor with an unbalanced output shaft. If you should happen to find a small enough motor you can always add the weight yourself, but usually motors this size are made for pagers anyway. I got mine on eBay for a few bucks; you can also get them here, for example.

The kind that I got are happy to run on almost any common voltage– probably a range of 1-9 V. As a power source, you can use an alkaline or lithium coin cell or watch battery, either 1.5 V or 3 V. To hook the motor to the battery I soldered short copper wire leads to the motor terminals.

Parts   Apply Tape

The last substantial ingredient is some foam tape. Apply a small piece to the top of the toothbrush robotic platform, which will be used to hold the motor in place.
Stick on motor   Cute but unstable

Attach the motor to the foam tape. The tape provides a spacer so that the rotating weight does not hit the toothbrush head. It also provides a strong, flexible connection to the base that is able to handle the severe vibration that this robot experiences. A first approach to hooking up the battery might be to stand it on end. However, the battery itself is not held in place very well this way and will fall out shortly.
Lead form   Enterprise

A better method is to bend one of the leads down flush with the foam tape, so that you can *stick* the battery to the foam tape as well and still make an electrical connection. The other lead contacts the other side of the battery, and the motor can run.

Lithium cell

The completed BristleBot, running and ready for action. When you set one down, you may notice that it tends to steer left or right. We have found that battery and motor placement, bristle shape (one stray long bristle can interfere with the motion, and motor rotation direction all influence the behavior- so be sure to try flipping the battery upside down if you have trouble getting yours to go straight.

Now and for the record, this is one of many different kinds of vibrobots– there are a lot of other designs out there if you go and look. We have heard of and seen many other vibrating robots, and we know that even using a brush with angled bristles for propulsion has been done before. However, this particular miniature implementation may be unique, and is certainly fun. Very few robots that you can build so easily are so rewarding. With the right parts, you can make one in a few minutes. It might be great fun to make a bunch of them to race them competitively.

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156 thoughts on “Bristlebot: A tiny directional vibrobot

  1. You guys RULE. That is the easiest, most hilarious thingy I’ve seen in ages. My 8 year old just watched the video over my shoulder, but left near the end to go rummage through the bathroom drawers for a toothbrush.

  2. I forgot to mention that I love the fact that yours is directional, and not just a dancer. I’ll have to make one up.

    You can get the pager motors from old cell phones. I pulled one just like yours out of a Nokia. My office has a bin for recycling batteries and phones, so I liberated about 10 motors from Nokias, before they went on to recycling heaven.

    – pepik

    PS That’s my pumpkin down there on the right!

    PPS Not to make you feel bad, but I can almost see Magnolia from my desk (Mopac’s in the way).

    • Oh fine– bring up Magnolia! Ha!

      I’ve seen your ‘bots– I looked around at most of the other vibrobots just to make sure that there weren’t any *exactly* like this one in obvious locations. I like how tiny yours are (you can probably tell that I like tiny electronics). It seems like the directional aspect really adds a lot to the project– these are *fast,* which adds a bit of excitement.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  3. i really love the bristle bot but……i dont want to rip my parents or brothers celphones up in the process. can i buy them somewhere? plus what kinda magnet did u use would a smalll donut magnut work?

    • A family without any already-dead pagers or cell phones? Surprising!

      There is a link in the article to Electronic Goldmine, who sells pager motors; there are many other sources as well. Expect to spend $1-3 each.

      Not sure what kind of magnet you mean– there aren’t any used in this project except those inside the motor.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

    • …? magnet???? did you READ the thing? that is no magnet, but a lithium (or alkaline) button cell battery. If you’re in the US, you can pick them up at radioshack or walmart. i really dont know about the UK. =/ the only magnet in that picture is the one in the dc motor…

    • I have already ripped apart my moms cellphone for the motor and got grounded.
      But it was worth it!

  4. Is the disposable electric toothbrushes. I seem to remember Crest having one at $7 or so.

    The head of that sort of toothbrush is generally oscillating-rotary though. So it wouldn’t be directional unless you used the head from a normal toothbrush.

  5. this is such a fun robot to make.
    i’m also glad it has no circuits and wires, since i’m such an electrical-silly.
    i’m going out to buy the stuff right now.
    thanks!

  6. This is so incredibly cool…. thanks for sharing!

    I’m thinking with some matchsticks or paperclips, you could have a mini-deathmatch with bristlebots.
    I just suggested it to the teen Librarian here, and hope that it comes to pass for our young adult patrons.

    C’mon – robots, pit fighting, and literacy… how is this not cool?

    Also good for the Nephews for Christmas. I’ll be the coolest Aunt ever.

    Maggie

  7. I made one of these last night and hilarity ensued. I ended up trimming the bristles to a shorter length as the top-heavy bot kept falling over. The only other issue is the ‘top’ wire connection is difficult to keep connected to the battery. Consequently, the bot putters around like a toy boat in a bathtub. Entertaining, yes, but I’d like to see this thing go :). Any suggestions?

    • >The only other issue is the ‘top’ wire connection is difficult to keep connected to the battery.
      > Any suggestions?

      First, we’re using solid copper wire that keeps a shape well. If you aren’t, things are a little more difficult, you might use tape to keep the leads in place.

      Secondly, prebend the top wire down, further than it needs to go. Then, when you want to put the battery in, the top wire acts like a spring that wants to hold the battery down. That makes a pretty good contact, as you could see from the video.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  8. This was so fun to make! My motor I pulled out of a old handheld Cd player, I put a blue thing from the circuit board on the end and attached it. my toothbrush has the tongue brush on the other side so I just used tape to hold it on. My cat went insane when I let it go on the floor!

  9. Hi! I just stumbled on this…
    This is just a great idea! I gotta try it some time,
    but i woult like to make them rechargeable by using a supercap.
    Does anyone know how long the little motor could run with a supercap?

  10. Next time you should extended the tape towards the cut off neck and added a couple googly eyes on the end for effect. Awesome job throwing this together, pretty entertaining and simple to make.

  11. Grammar aside, I never said that this was the first anything– just that I hadn’t *seen* any that used a toothbrush for propulsion. Obviously, just because I haven’t seen something doesn’t prove that that something does not exist.

    If you do have an example to show, I would be very interested to see it.


    Windell H. Oskay
    drwho(at)evilmadscientist.com
    http://www.evilmadscientist.com/

  12. hahaha that is the coolest thing i’ve seen in a while :) where do you get those pager motors?

  13. Great project, Windell! Thanks. I just helped my 5 year old son and his 7 year old friend build two of them. Done in 15 minutes. We only had regular old toothbrushes with slightly longer bristles on one end, but we squished the bristles outward to give a more stable base. We added a strip of foam tape hanging down across the motor and added #8 hex nuts as weights to lower the centre of gravity and try different behaviours.

    DW

  14. This is a REALLY cool idea. It reminds me of those American football (gridiron) toy games with the vibrating field and the players with the angled plastic tabs as legs.

    As a variation of the Bristlebot, I would propose replacing the battery with a solar powered BEAM engine …

    http://www.beam-online.com
    http://www.solarbotics.net

    It would move a LOT more slowly but I believe it would be more interesting.

  15. u are mad i love the bristlebot it is so ausome how do u find out things like that?

  16. Hi. Great stuff as usual. My robot tend to start spinning after a few seconds… Any tips to avoid that? Many thanks Tom

    • As it says above, "We have found that battery and motor placement, bristle shape (one stray long bristle can interfere with the motion), and motor rotation direction all influence the behavior- so be sure to try flipping the battery upside down if you have trouble getting yours to go straight."


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  17. That is pretty neat, might be interesting if they are dipped in paint and
    let go on some paper, get lots of colors going for robot art.

    Alan

  18. You could actually get the motor from one of those "sonic" disposable toothbrushes, they look just like the one you used.

  19. We were building bots in class, one of the students brought in a ‘Oral-B Pulsar’ which already has a pager motor and battery inside it. We were able to rework it. One stop shopping.

  20. I’m trying to make the one with the IC chip. Hope all goes well, like when you cook good eggs…

  21. Hello, we’ve spend a fortune of various 3 volt and 1.55 volt batteries and they burn out after being just tested with the wires! We had one work for a short time and another for a longer time. Otherwise, the other four literally lasted one-two seconds. The batteries came from Radio Shack and Target. Any advice? Thanks

    • Sounds like you had some bad batteries there. It shouldn’t be possible to drain a battery in 1-2 seconds, no matter what you connect across it. We have, however, seen some bad batteries that stopped putting out useful current to our motors in just a few seconds… we replaced them with good batteries and problem solved.


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  22. If you fancy something a little bit bigger, take a look at the Bristlebot Waltz video on You Tube.

  23. add a Ultra Ultra Ultra Ultra Ultra Ultra Ultra Ultra Ultra tiny microcontroller to steer it (move a small weight)

  24. This project entertained 10 kids from ages 2-13 for most of a day. Thank you, EMSL, for being the ORIGINAL creators of this fun project.

  25. Fun!
    By the way, another source of vibro-motors should be handheld massagers. For some reason we have been given two of these we don’t use. I’m taking one apart now. It takes 3 AAA batteries though, so maybe it can’t run off a watch battery.

    • Hi.. I’d recommend using the "pancake" motors and a 10F200 PIC, as these are really compact and will usually run from 3V as well as the direction being determined by rotation.

      Also not all batteries are created equal, if you buy the cheap ones then they may not work. You might have better luck buying a 12V lighter battery and gutting it :)

      -A email testing_h@ya2piroo.com

      replace the radius with h to email

  26. I just tried this with a motor from a dead cell phone, but with no success. First, scotch heavy duty foam tape doesn’t stick to the motor at all: the motor literally rolls off before it’s even turned on. Some masking tape was more effective. Next, the motor doesn’t have solder points, just stranded wire exiting the motor housing, so there’s no way to hold the battery with the wires. I slipped a bent paperclip between the bristles, which sorta works. Finally, with everything mounted and running, the bot simply falls over and rattles in place. The bristles don’t provide a stable platform.

  27. I’d like to point out that the concept first was exposed in the BEAM mailing list ca. 1996-1997 by some guy who was extremely anti-Tilden and was kicked off the list shortly afterward. He suggested using a "slicker brush" (see photograph at: http://www.precision-dog-training.com/images/Slicker.jpg ) and a vibrating motor. BTW, the tines of such a brush are _extremely_ stiff stainless steel, are quite short, and have a small enough diameter that if you happen to hit yourself with it you might end up with a small area of punctured skin (and all that goes along with that). One other thing about the bristles is that they are all pre-bent and inserted into the head of the brush in a regular array so directionality is assured.

    Signed: The BEAM Heretic (aka Your Friendly Hogfather)

    • As we have pointed out repeatedly, the "concept" actually goes much further back than that– it occurs in nature, and patents for controlling motion that go back to at least the 1950s.

      I think that a brush like that might work well for a human-rideable Giant Bristlebot!


      Windell H. Oskay
      drwho(at)evilmadscientist.com
      http://www.evilmadscientist.com/

  28. ok well can you guesstimate a total price for this im in school so i dont have that much money right now

    • A dollar and 10 minutes given you have tools and can scavenge. 0 dollars if you’re good.

  29. i found a few old cellphones in my dads desk and i ripped them up to pull out the motor and i cant find the toothbrush the guy used cause they’re not available in Canada and i live in Canada.

    • if you live in Canada & you want to make a bristle bot you can buy a book called invasion of the bristle bots by klutz press its available in Canadian bookstores such as black bond, coles, and chapters or just go to indigo.ca or just come over to America its available at Target if u don’t know what Target is its American version of Zellers (i been to Canada before) and u can buy the toothbrush there too.

      • it’s fun! i made 1 with dad 2 day using toothbrushes made in USA tape made in somewhere i think Egypt and motors and batteries made in Mexico so fun!

        WICKEEEEEEEEEEEEEEEEED!!!!!!!!!!!!

    • the toothbrush is the oral b cross action vitalizer. available at shoppers drug mart.
      ~Trashman244~

      • wtf i took a cardbord and a motor and stuck a eraser on the motor and got a battery (9v) and toothbrushes stuck everything together it was fun until the tabs of the motor fell off now i have to go to radioshcak and waste 10 dollars

  30. You CAN put it on standing up; you just need to stick a tiny magnet near where you want the battery to be. this way it’s easier to remove the battery.

    • It looks like those bots might work better with angled bristles. If the bristles are just straight up and down then the bots don’t move too much like the ones in the video.

  31. Another great source of vibro-motors are from the operation game. make sure it isn’t the silly sounds one. it has to be the one with the brain freeze or something similar to operation.

  32. two toothbrushes already come with motors and batteries already!
    braun pulsar:http://www.toothbrushexpress.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=TE&Product_Code=OB29&Category_Code=oralb
    Colgate 360 degree sonic power:http://www.amazon.com/Colgate-Sonic-Power-Soft-Toothbrush/dp/B001KYVQ8A/ref=sr_1_1?ie=UTF8&qid=1249778830&sr=8-1
    but the Colgate 360 degree sonic power has a tongue scraper, which can be removed with a knife. the wires in the sonic power make great wings, too!

  33. The wires on the sonic power toothbrush make great steering things too. also makes great balance wings or supports.
    _____________________
    l
    l
    l
    l
    ________________________ OOL!!!!!!!!!

  34. Canadian stuff works good!
    The exact cross bristle ‘brush from loblaws superstore in Canada is a great ‘brush!
    I’m not Canadian but i been there before.
    also if you smoke check out the guitar novelty lighter. it’s a Canadian exclusive!

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