This post compiles four descriptions of the process of turning small motors - wind-up or battery powered, storebought or harvested from disused toys - into creative homemade automated toys. It offers instructions for making three robots using three different powering mechanisms and achieving three distinctly different effects, but all using the same basic principle of an eccentric weight on a motor that makes the motor vibrate. Be warned: Rubber duckies were decapitated, craft gourds were painted pink, and at least one motor was destroyed by super glue in the process.

A few days later than I promised, but the reasons were interesting. More on that next week!

Harvesting motors

Z is strangely attached to the Bee Movie figure at left in the photo above. No, she hasn't seen the movie - she calls him "Andy Ant," after a favorite childhood book of mine we've passed down to her, this despite acknowledging that he is, in fact, a bee. He does a little bee dance, standing in place and wiggling his arms and body, when you wind him up, and I guess she thinks it's cute or something. But we both agreed that the bee at right, who swings his arms around, truly sucks. So we decided to take his motor out to make a new toy.

Most toys for small children use "tamper-proof" screws with triangular slots. They are not, in fact, tamper-proof. Just get a cheap set of precision screwdrivers and find one with a tip the length of a side of the triangle, then use a bit of extra muscle to dig deep and you'll get that screw out. This little guy had three - one on the back of his head, one between his wings, and one down by his rear. In five minutes I had extracted the motor, positioned his little arms and legs back in place, and closed him back up tightly.


Here's the motor. The winding key was held to the motor by the bee's body. You wind the motor by putting the key on that white wheel and cranking it, and power is transferred to pins on either side - one had previously powered each of the bee's arms. At this point, when you wind up the motor it dances frantically around on the table or floor, skipping over its various faces and rattling around. I know we have something good going here - Z already thinks this thing is waaaay better than the toy we ripped it out of. My hidden agenda is for us to have so much fun making this toy she'll soon think Andy Ant sucks, too, and she'll want to pull his guts out as well. We'll see.


The Lamaze-brand caterpillar at left in the photo above has a fabric-wrapped pull string that stretches it out like an accordion, with a motor in the head that then propels the caterpillar forward as the motor in its head wraps the cord back up. The lingering infant toy has been a target of mine for a while, but I chose to buy our first motors because the last time I brought up the idea of destroying the caterpillar (months ago) Z was very resistant to the idea.

I'm pleased to report that my strategy worked. After having a lot of fun with our storebought motors, a mere mention of the gorgeous motor this caterpillar must have inside its head was enough to send her running for scissors.

The chick was a conditional purchase in the $1 section of Target. She verbally consented that we were buying it to rip the motor out, and that "there wouldn't be any chick left" when we were through with it.

First we stripped off the caterpillar's skin to make sure it worked the way we thought it did.


Then we surgically removed a surprisingly large motor from its head.


Above, the chick without its downy fur (furry down?).


One thing that surprised me about these reclaimed motors was how much more powerful they were than they seemed to be when inside their toys. The caterpillar's motor, housed in a hard plastic shell I think we'll leave on, packs a serious punch. Much of that energy was translated into movement in the original toy because of the caterpillar head's very tight filling - we tried outfitting one of her smaller stuffed animals with the motor, but the softer fill absorbed all of the motor's vibrations - but once freed the motor vibrates so hard I didn't want to run it on the table for fear of damaging our furniture.

Likewise, the chick motor, which caused the chick to peck and hop pretty gingerly when you wound it up, dances frenetically without a body to weigh it down and confine its movements. It can hardly stay on its feet.

Vibrational Walking Robot

Walking Robot, Pull-String Motor

This robot utilizes the eccentric-weight motor we harvested from the caterpillar above; the motor has a pull string and is encased in a cool plastic housing. We replaced the fabric handle with a wooden bead, wrapped the motor in two lengths of wire that terminate in four legs, and started decorating.


I selected a small gourd grown in our garden a few years ago for a body, used masking tape to attach it to the leg armature, and Z chose to paint it pink. That led us to consider a PVC rubber duckie we'd been meaning to get rid of because it may contain phthalates (the irony: it's pink because it's a breast cancer awareness rubber duckie), which we promptly beheaded. Z had the inspiration to put a bell in its head, which turned out to be a stroke of genius.


Her second moment of unanticipated brilliance was one I gently resisted at first: She wanted to paint the duck's head pink as well. This is simply because she loves to paint things, and I was concerned the creature would lose some of its personality in the process. Nothing could have been further from the truth.



Robots look better with sequins.



This robot in action:

Jumping Robot with Corded Remote

I purchased this small motor for about $3 at Radio Shack. It has two little contacts for wires on the back and on the front has a single pin that spins when it is powered. We stuck a plastic wine cork on the pin as an eccentric weight, which means that as it spins it makes the motor vibrate. The further off-balance the weight, the more it jumps.


Actually, it took two motors to make this robot; we attached a shell made out of the wings of the pink duck, but we used superglue to attach them to the motor, which was fine but then we started adding pompoms and then lots of little plastic train set people riding all over it and eventually the motor stopped working - we either got superglue in the motor itself or it ate up the wiring. We had to remove all the parts, sub in a new motor, and decided to use only electrical tape this time, forgoing the shell.


The wire "leash" actually plays a key role in this robot's functioning, helping it to keep its balance far longer than it did with lighter weight cord I used previously.

The corded remote for the robot is shown below - a 9-volt battery and a button housed in the plastic container that previously held small hardware of some kind. A box from a deck of cards would have worked equally well. It was my father's brilliant idea to replace the very short cord I originally had leading from the remote to the robot with a longer one so that the user could stand up and "walk" the robot.


It may look complex, but I have no experience in this stuff and it was a piece of cake to hook up. The 9-volt battery hookup comes with two wires coming out of it, which you connect to the button and to the incoming wire, and the other yellow wire connects to the other contact on the button, creating a simple circuit with the button as an interrupter.

You can buy everything you need at Radio Shack; here's a link to their web store's Component Parts shop.


Again, one of the best features of this robot is one of Z's random innovations: The little piece of ribbon we tied around its middle as decoration frequently gets in the way of the head, and makes a nice "thwip-thwip-twhip" sound. We're quickly learning techniques we'll be applying in the next generation of robots we'll be designing sooner or later.

Watch this robot in action:

Wind-Up Drawing Robot

The third robot in our series of homemade robots (1,2) uses the wind-up motor we harvested from a lame Bee Movie toy. (Ah, I get it now... "Bee Movie." Heh.) It draws with marker legs as it vibrates around on a piece of paper. We developed this based on an idea I saw here, which was actually what got me interested in creating toy robots in the first place.

We used a cheap plastic cup as the body of the robot, taping the markers to the interior cup wall. Since this wind-up eccentric-weight motor is relatively weak, we ended up cutting down the cup to about half its original size to lighten the load.

The trickiest part was incorporating the motor into the body of the bot so that only the winder was visible. The toy the motor came from was similarly designed, so when we removed the motor from its bee case the winder popped off. For a while we used it as a sort of key to wind the motor, but I knew if we stuck with that it would soon be lost, and I didn't want to glue it onto the motor for fear I'd gum up the gears in the process.


After covering the cup and markers in masking tape - a technique I came up with to allow for easy painting on plastic surfaces that also gives objects a cool papier-mache look - I positioned the motor inside the cup and cut a hole in the side to put the winder through. I carefully taped the motor to the cup with several small strips of tape, making sure not to block the action of the small eccentric weight on either side. Then I inserted the winder through the hole I'd made and taped around it to decrease the hole size so that the winder's peg, which had a head larger than the stem, was locked into the cup.



See this robot in action: