Making a Gyarados is, in concept, simple. However, when implementing, it is quite difficult.
Slides: Gearados Presentation
The first step is to choose a mechanical movement. We decided to choose #92 because it changes rotational motion into translational motion.
Low + Medium Fidelity Prototypes
Here is the original sketch of our idea:
To begin, we began low fidelity prototyping with cardboard. Instead of gears, we started off with cardboard circles to minimize friction and show the concept of the gears spinning with each other. Here is a picture of the low fidelity prototype:
In our medium fidelity prototype, we laser cut the box as well as the gears out of plywood. We used popsicle sticks connected by thin pegs to imitate the hinges we planned to use to translate the motion. We also cut holes in the top with straws as guides that were supposed to ensure that the sticks would move in the vertical direction. Here is a video of the medium fidelity prototype:
The lego on the box raised the lid because it was too low and the short hinge was hitting the top. One issue was that the sticks weren’t going up perfectly vertically. Another was that the gears were not aligned perfectly, so they caught sometimes when spun. We fixed these in the following final prototype.
Final Prototype
For our first iteration of the final prototype, we decided to double up on the gears to align the gears. We also doubled up on the back wall so the bearing would be embedded in the wall since it was thicker than the plywood. We added bearings to make the mechanism smoother. We also replaced the straws with laser cut rings underneath the lid. Here’s a video of one of the gear and hinge sets working:
However, we had a huge issue. There was way too much friction between the alignment and the vertical hinge because the hinge was not going vertically up and down. We reexamined the mechanical movement diagram and redesigned the hinges to have the right dimensions in our next iteration by lengthening the hinge attached to the gear.
To further ensure that the gears would line up, we pushed them all to the back of the wall. We also decided to move the bearings from the gear to the wall so it would not be as shaky. For the small gear, we lengthened the dowel to reach from the back to the front wall to stabilize it. For the hinges, we also made them much larger in addition to making them accurate to the mechanical model. Each bearing was upscaled to a larger bearing for maximum longevity and stability.
We changed the alignment model by adding guard rails along the back wall and an acrylic ring around the top. This was also taken directly from the mechanical model, and helped greatly in making sure the hinge stayed vertical since it began from the bottom of the vertical hinge. Here is a video of when we got the mechanism working.:
The handle was our water jet cut piece, and it is the shape of a fish because Gyarados is a water Pokémon. We designed the file and cut it with 6061 aluminum. We filed and sanded it to create a smooth finish. It was press fit into the dowel connected to the small gear. The other hole was for a bearing connected to the handle so it turns with the user’s hand. In contrast with the previous design, we put it on the front wall for convenience.
We decided to make the front face out of acrylic so users can see the inner gear mechanism moving as they turn the crank. Unfortunately, the only piece of acrylic we found had some scratches on it. We designed the front piece with waves on top and fingers that would connect to the existing wooden box. We cut a ring of acrylic so the bearing would fit into the wall.
The top was the most difficult part. We laser cut two 2D profiles of the Gyarados, which were connected on each side with wooden sticks and connected to a ribbon.
They were then pressed onto the sticks that moved up and down. Although it’s a bit wobbly and the pieces look slightly disconnected, it works when you crank it. If we did it again, we would put two ribbons to make it more stable.
Here is a picture of the final product:
If we had more time, we would have post processed the pieces better and been more thorough with looking for mechanisms to use.
Cost Analysis:
⅛ Plywood – 1 sheet: $6.04
Bearings – 12 bearings: $6.99
Aluminum – 1 block: $31.90
Acrylic – 1 sheet: $3.50
Wooden dowels – $6.29
Ribbon – $0.30
Time – $15 x 30 hours = $450
TOTAL: $505.02
