Improved printable eggbot

thingiverse

Watch Eggbot in action here: http://youtu.be/w5YWRMa1uJk. To create your own and enjoy designing custom patterns, use the Eggbot on eggs, balls or even light bulbs. In my modified version, I improved the end plates for better pen travel and removed redundant features like the top front hole for an M8 stud in the original design. The overall height of the end plates could be reduced, but I chose not to as it offers protection to the pen arm and vertical space for electronics mounting. Angle brackets on either side at the front take out flex from the end plates, ensuring proper alignment of drive shaft and idler shaft axes. Drive and idler cups now feature nitrile O-rings for accurate egg centering (ARP-206 - 3/4"OD x 1/2" ID). The constant outer diameter allows for easy alignment using a straight edge. I used an HXT900 9g servo, modifying the spring to fit the servo arm's center. For electronics, I chose the genuine EBB (available at http://shop.evilmadscientist.com/) due to its tidy one-board solution, software support, documentation, and comparable price to an Arduino Uno plus Adafruit motor shield. The EBB came preloaded with firmware, making it easy to use out of the box. Instructions for assembly can be found in photos, suggesting 300mm studs, but 200mm would suffice unless using large eggs or printing light bulbs. O-ring cup design is an option, though I have no comparison. EBB electronics are fitted with M3 screws, and the bracket is secured with M8 nuts against end plates. Extensive guidance on using EBB can be found at http://egg-bot.com/. Inkscape extensions allow you to create artwork, control your Eggbot, and plot directly onto an egg within a single free package. To complete your set, grab a bundle of colored ultra-fine Sharpies for Easter! I also added an M4 thumbwheel (http://www.thingiverse.com/thing:13807) to make pen changes more convenient without needing a screwdriver.