Autonomous Robot Part 2 – Donatello – The Turtle Bot



We started this project with the goal of creating a robot that makes its own art. Donatello is a simple robot designed to draw turtle graphics on whiteboard tables. Named after the teenage mutant ninja turtle, Donatello uses a two DC motors, a dry erase marker, and a webcam to move around, draw lines, and see where it has been. The body of the robot is constructed out of open beam components and custom 1/8th inch plexiglass laser cut pieces. Donatello uses a raspberry pi as a brain. The pi is running a custom python program that uses the wiringpi and OpenCV libraries. The future holds many possibility for the logic that Donatello follows. The current rendition of the code has a simple two state system. When the camera detects a blue line under the robot it drives in a zig-zac line, when no line is detected under the robot Donatello draws a slowly drifting spiral shape.

Below are detailed photos, code, and diagrams that should help you build your own version of Donatello.


The first diagram of the robot. (top view). NOTE: The second marker has been replaced with a wheel.



The robot drawing a line.


An early attempt at drawing lines. (one of many)


View the code here. 

The electrical diagram of the robot.



What the robot sees. (the small window near the mouse is the computer’s view of what is blue)