Doodle Bot - beginners platform
The Doodle Bot is a very simple robotic platform for beginners, students and hobbyist.
The Chassis is a simple laser cut panel with two ball raced geared motors and a servo for raising and lowering a white board marker, jumbo chalk or crayon. Each wheel is fitted with an 8-pole magnet that is monitored by hall effect sensors to form two simple wheel encoders.
[original story: Let's Make Robots]