Embedded Files
Buttons click & work, wheels spin. Backup key built into the trunk, which slides backwards with a spring detent.
Wood PLA body (30% sawdust, 70% PLA) printed solid, feels like it was carved from a block of wood. 15-5PH wheels (SLS 3D printed) & reamed to slip fit around small shoulder screws, screwed into a standoff that's epoxied to the body. Circuit board cutout is underneath, held with automotive silicone glue (for battery replacement purposes).
https://www.thingiverse.com/thing:4878008
(the files are a little old.. the body/battery cover are correct but it doesn't include the wheels)
Finished project!
Rear view showing the trunk installed
Rear view showing the trunk/backup key removed.
Freshly after installing the stainless steel wheels with the old PLA plastic wheels next to them (I got tired of reprinting them every time they broke, so metal printing was next)
Closeup of an installed wheel
CAD rendering of the wheel. Remix of a TE37 model I found online (I have TE37SL's on my car so the key had to match), and adapted to meet minimum wall thickness for SLS printing. Also had to design in the counterbore for the shoulder screws I used as axles.
CAD exploded view of the car body with wheels.
I found an STL of an RF Miata but the mesh was in bad shape and needed cleaning up in blender. Then I imported it into CAD and made the cutouts for the circuit board, trunk, ball detent, axles, & buttons
Same model viewed from the bottom. Here you can see the standoffs I used as axles (epoxied in) and the button holes. The circuit board goes on the floor, battery facing out. (I'll add photos of the mounted board next time I need to change the key battery)
I sized the car by width, you can see the thin walls behind the wheel wells on the inside. This was the smallest I could make the car while keeping the PCBA enclosed and not changing the proportions of the car. This made the circuit board just barely fit between the axles length-wise as well, there wasn't room for a more elegant mounting solution for the battery cover. If I do a version 2 I'll work on that.
The battery holder. I was able to reuse the factory battery clip, the battery snaps in place. I attach this to the bottom of the car with automotive silicone to help seal it.
I have to remove the cover to change the battery. I've changed the battery twice now as of this writing, the bottom cover is not reusable and requires reprinting (~15 mins, PLA)
View of the stainless steel wheels as-printed, with the PLA prototype below
Old PLA wheels installed (before the TE37 design). I printed them face down on a flat PEI sheet to get the outside flat and shiny.
Early prototype out of normal PLA. The wood PLA is highly abrasive and destroys printer nozzles quickly, so I did the test fits out of the cheap/easy PLA
Underside of the prototype & battery cover. Notice the battery cover doesn't have the full overhang as the final CAD version above, I found I needed more real estate for the silicone glue to adhere to. This version also didn't feature spinning wheels.
Finished first pass at wood PLA, including wood stain. Doesn't feature spinning wheels or removable trunk. OEM Mazda key on the right for comparison.
Page updated
Google Sites
Report abuse