This fantastic video popped into my inbox the other day from Mark Vandiepenbos. I watched as this creepy young woman was carted around by the toddler on the tricycle and got chills when I saw that little doll head turn. What a fantastic costume!

Every year we make a costume for our daughter. Being a maker, we assemble and build from recycled parts and materials. This year I had the idea of making a toddler on a tricycle pulling our daughter around. Initial concept was to make everything foot controlled to give the illusion of the toddler peddling and steering.

At first glance, the construction of this system wasn’t completely obvious. Mark cleared that up for me a bit.  He basically grafted a custom frame onto the rear end of a tricycle. He used the 24V electric motor from a stand up scooter that had a burnt up controller.

1016161706You’ll note that the toddler’s legs move laterally as the wheel turns left or right. This is because Mark added Hiem joints to the hips of the little toddler when he made it, so that it would have that added flexibility.

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Deciding how to steer this contraption turned out to be more difficult than Mark initially envisioned.

First try with the steering was to use a jointed arm with a gear motor pushing and pulling on the bars, once built it was good to pull the bar but having to be able to move side to side it was too floppy to push, so this was all scrapped and I fabricated a drum and cable system to steer with also using a 12v geared motor for turning the spool.

Once he had all of those mechanical hurdles behind him, it was time to wrap things up, give it all a nice layer of padding and clothes, and be done! However, when he decided to make the toddler’s head turn, he found that he had to do some custom design work.

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He design and 3D printed a custom gear system, mounted with a hacked servo for the rotation.

As Mark stated above, they’ve been making awesome costumes for several years now. Here are a few from the past.

 

And just to show that even if you have made a ton of awesome things before, you are always learning.

For this project I learned about making working joints, designed and built a cable steering system, learned how to hack a servo to do 360 degree motion.