The mechanical subsystem serves as a physical base for wiring, arduinos, and motors. The actuation of the 'surprise' inside the top clock was also designed as part of the mechanical subsystem. The CAD files for the parts and assemblies are located in the gallery's Laser Cutting/Engraving folder.

Final assemblies for the lighthouse clock on the top, and for the motor mount inside the base (rotary) clock.

Final assembly for the rotary clock, showing handsome wood grain.

Final assembly for the cake clock, looking rather dull because it only shows the outer drum. There is an inner drum inside it, but it's basically just a circle because we don't have CAD files of the supports.

The table that sits inside the cake clock, serving as a motor mount for the cake motor.

Fabrication methods:

We designed the parts to be planar so that they could be laser cut, which meant that we used many flat faces in our design rather than curves. Since we were already using the laser cutter, we embellished the clock using laser engraving. In our initial iterations we cut teeth into the edges of each face so that they could interlock, which made more contact points, but we opted against that because we preferred the look of the pieces without the teeth.

When laser cutting the final pieces, we used the Trotec laser cutter instead of the Helix because it was more accurate and left less pronounced burn marks. With a laser cutter like the Helix, we would have had to spend more time sanding to clean the pieces up.

Some parts did not require the level of accuracy of a laser cutter or were much thicker than the wood we were laser cutting. We cut the wood for the table, dowels, and support blocks by hand. In order to connect the faces, we beveled the edges by sanding them. We measured the angle we wanted and made triangular pieces of wood that was cut at that angle and used it as a jig to sand the pieces down. We found that it was challenging to sand at an even angle across long pieces, so it was important to run the piece across the sander. It was important to check the bevel periodically to make sure the angle is correct and none of the length of the piece has been sanded off.

When assembling the laser cut and manually fabricated parts, we used a few different strategies. We primarily attached the pieces that needed a lot of structural stability with wood glue, and if we needed to work with it quickly we used a little hot glue to keep the parts in place while the wood glue was drying. We used hot glue for other parts that we anticipated needing to alter or parts that were not as structural. We also used brackets and hinges with screws for reinforcement and to make doors to access the inside of the pieces.

Challenges:

Because we have rotating parts, we had issues getting them not to wobble. Centering the pieces exactly reduced this problem and creating more stable surfaces were both ways we addressed this problem. To create a more stable surface for rotation for the outer drum of cake clock, we made a table for the motor mount that has more surface area that contacts the outer drum but has low friction because we used slippery surfaces (electrical tape and smooth hardboard).

We also, at the last minute, realized our motor wasn't powerful enough to rotate the outer drum, so we instead decided to have just the carousel animals rotate, by attaching a disc to the motor and hanging the strip of animals from it. Less weight! Nice.