Tasked with making a drawing machine, I wanted to use an unconventional medium and learn more about molding. I 3D printed a model of a monkey skull, set a silicone mold around it, and poured melted crayons into it. The skull sits on a vibrating table made with a Arduino controlled subwoofer and moves around as it vibrates creating interesting patterns related to its shape.
The project began as a learning experience in mold making. I knew that I would have to make one to build the skull, but had no prior experience with the process. After emailing my art class professor I settled on a single piece silicone mold and set about making it. I started by 3D printing the model of the skull and then set the mold around it. The mold held heat a lot better than I expected so I pulled the first attempt out too early and it came apart, I learned from that mistake for future versions.
Once I had worked out a process for making the skull I started working on a way to make the vibrating table. Originally I was going to use a non-centered weight attached to a servo, but my early prototype didn't make enough vibration so I ended up looking for an alternative.
The mechanism that I settled on was a subwoofer that I bought from Goodwill. I needed high frequency vibration that didn't displace the surface too much so that ended up working really well. As always I started with a prototype and worked up to a final version. I took apart the original subwoofer and scavenged the parts I needed, hooked the speaker up to a power supply to work out how many volts I needed to supply to it to get the type of motion that I needed, and then wrote a script to control it with my Arduino.
Having prototyped all of the components I set about building the final enclosure and wiring a switch and power indicator light to the subwoofer to indicate to users when it was running. Breaking the project up into smaller parts made the final build fairly straightforward.