Crayon Car, Prototype 1

Fun yet again with TPU, this time with flexible axles, and CRAYONS! A few weeks ago, a video appeared in my recommended video feed from Tim at GrandIllusions () showing a crayon line following toy car designed forty years ago that had no electronics whatsoever, but no operational details were provided (Tim was perplexed regarding how the car operated). Not long after that, John at RobotHut () sent me a link to a video of a design he created of a three motor version of the crayon following car (P.S. if you like robots, RobotHut is the place to be!). Anyway, between the two videos, I designed this single motor crayon following car using a flexible 3D printed TPU drive shaft to transfer rotary motion from the rear wheel to the front wheels. The theory behind the design is elegantly simple. A single rear wheel drives the car forward while the counter rotating front wheels “sense“ the crayo