About Crayonbot
This is a robot that draws. It was constructed using hobby servo motors, drawer slides, lucite, PVC pipe, aluminum, a tin can and peanut butter jar lids of various diameters, picture frame hanger wire, and other stuff that I tend to hoard under the usually delusional theory that I'll build something out of it someday.
It has a webcam. It can try to draw something that it sees using the colors of crayons or pastels that it has been told are in its rack, or it can load an image file and try to draw it. It can draw unattended with crayons for hours on end. Pastels are more fiddly and require more interaction, but the results are more satisfying.
The pastel drawing on the right was from the webcam, and the one on the left is Gort, the robot from The Day the Earth Stood Still.
The software is an old-school Windows C application to handle motor control and resampling and repalettizing BMP files or frames from a webcam. I put a fair bit of its configuration into user-editable text files, which allows me to switch between crayons, pastels, rack colors, paper types, drawing resolutions, brush strokes, and pressures without having to change the software.