We were tired of drawing and painting large scale art and murals. We thought to ourselves "There has got to be a better way to do this." Printing pictures on paper seemed so easy comparatively. So we set our minds to building a robot that could print mural size images.
What it does
It prints a mural using a spray paint can that sprays large murals from images you upload to it. It converts an image you upload to it into "pixels" the size of a spray dot. It then sprays these "pixels" as it progresses vertically from column to column till the image is done.
How I built it
We used a high torque non continuous servo to rotate a cam that depressed the spray nozzle when desired. Two other continuous servos ran two wheels that drove and steered the robot. A third freely rotating wheel with caster provides stability for the bot. The frame is made from modular steel and aluminum. The bot is powered by AA batteries and uses a raspberry pi to run its program.
Challenges I ran into
Working under such a time constraint and on a project that had not been heavily pioneered before proved challenging. Especially with the limited amount of hardware available to us at the time. The robot's code took a lot of tweaking and fine tuning to get it to drive straight, spray properly, and turn.
Accomplishments that I'm proud of
We managed to make a functioning robot that could paint computer images on a large scale in the crunched timeframe of 16 hours which is no easy feat.
What I learned
We learned a lot about working under time constraints and how to properly control a bot to a high precision. We also learned a lot about frame design.
What's next for Mural Bot
We plan to add more colors eventually enabling the bot to print in red, yellow, and blue so that it could make photorealistic color images when viewed from far away.