Open Source Drawing Robot
Pollock is a 3D-printable drawing robot. It is based on the Low Cost Arduino Drawing Robot project on Instructables. The MK1 design took the original robot's chassis and extended it to support the standard driver boards you normally get with small stepper motors, together with support for an ultrasonic sensor. The new MK2 chassis reduces the number of parts and screws by building the motor brackets into the base. Little changes, like the position of the battery case holes and making the pen holder big enough for Sharpie pens have also be made.
The focus has also been shifted away from the Arduino to the BBC Micro:bit micro-controller (although Arduinos can still be used). The controlling code is now written in MicroPython and the chassis has been altered to allow brackets to be added to hold standard Micro:bit battery packs. The robot now rides slightly higher to give more space for these battery brackets. The whole chassis has also been remodelled and shared on Sean Clark's TinkerCad page.