Week 7: Dancing Cam Toy (MAT238)

For this project, I was tasked with building a toy mechanism that achieves a desired motion. I decided to go with this dance move because it has been a joke between my housemates trying to recreate it. This is probably the silliest project I have worked on, but it was cool to learn a new workflow within CAD

• 1/4" Plywood
• Wood skewer
• Fishing line
• Super glue
• Laser Cutter
• Photoshop
• Illustrator
• Fusion 360

I simplified the dance into two motions for the toy: the arms dropping and the legs oscillating as (somewhat) demonstrated in the sketch

For the character itself, I decided to use a screenshot from the original video. I removed the background in Photoshop and then brought the image into Illustrator. In Illustrator, I used Image Trace to convert the image into a black and white vector and I used the silhouette setting to create the red outline. I then duplicated the drawing a few times to isolate the chest, arms, and legs. I exported the outlines as SVGs to use in Fusion, and I saved the shading for when it was time to laser cut.

I inserted the outline SVGs into CAD sketches in Fusion which allowed me to add other features to them for integration with the mechanism (cam follower, side wall). I was somewhat surprised with how seamless this step went, I was expecting more issues.

To achieve my desired motions, I designed two cams. One has a gradual incline with a steep drop (for the arm motion). The other has a circle on one half, and periodic bumps on the other (for the leg oscillation).

The overall box was based on Alejandro's example box, and I adjusted it for laser cutting.

I exported the Fusion models as DXFs to import back into Illustrator for laser cutting. During this step, I reintroduced the shading layers into the design to be engraved. The laser cutter was a bit finicky. It took a few passes to cut all the way through. The finished result was a bit burnt, but that's ok.

I drilled a hole in the character's hands to attach them to the cam follower and used fishing line to attach the arms to the chest and act as a hinge. This was a bit messy, but it worked. The main box snapped together and all other fixed joints were glued.

The mechanism would need to be iterated on to work better. The wood is a bit light, so the followers do not remain in contact with the cams. I also overlooked the orientation of the engraved shading, so the arms and legs are flipped. This would be easy to iron out if I had more time for this project.