Make: Volume 52

I contacted Bob and he explained that

angled “legs” are the key to directional

movement. Folk toys often used broom

bristles or thin wooden strips, he explained.

Aha! Progress.

The next problem was devising a new

source of vibrations. Initially, I banged

drumsticks on a large plastic pan, which

did move my critters forward. Still, I sought

a more consistent vibration. I considered

speakers playing set tones, or motors with

off-center weights attached to their shafts.

After making little progress, I again reached

out to Bob. He sent me a video in which the

teeth of a gear turned by hand engaged the

edge of the track. How simple! Here’s my

classr ...