Alby Penney

apenney@andrew.cmu.edu

Sophomore in Electrical and Computer Engineering

One Wheel From Two

If you can't afford a One Wheel like those grad students outside CIC who let you ride it, just convert a hoverboard!

@apenney, @dbarajas

One Wheel From Two 22 Jan 2022, 10:41 p.m. EST
Day 1: Picked up parts and fully disassembled hoverboard (after some nerve-racking riding around techspark). We removed mounting brackets and attempted unsuccessfully to bolt together the two hubs.
One Wheel From Two 13 Feb 2022, 12:39 p.m. EST
Day 2: Discovered that the stator is removable, so we achieved the priority milestone of making one wheel from two and its only downhill from this point on.
One Wheel From Two 13 Feb 2022, 2:06 p.m. EST
Day 2.5: Completed full tire assembly and developed frame design sketches based on collected measurements from tire assembly.
One Wheel From Two 13 Feb 2022, 2:05 p.m. EST
Day 3: Short day, Continued frame design, 3d printed non-fitting hub supports far too many times out of PLA until we discovered the magic of flexible TPU 95.
One Wheel From Two 13 Feb 2022, 2:06 p.m. EST
Day 4: Frame day, ditched C-channel and used 80/20 aluminum extrusion instead to build first prototype frame with footboards.
One Wheel From Two 13 Feb 2022, 2:06 p.m. EST
Day 5: Created motor and battery wire harnesses, improved axle mounts and ran first big test which just made a lot of scary noises. (turns out BOTH bearings are necessary).
One Wheel From Two 13 Feb 2022, 2:07 p.m. EST
Day 6: Discovered a unique challenge to combining 2 wheels into 1: aligning the BLDC motor magnets. Initially the magnets were misaligned by 4 degrees, which is exactly half the width of a magnet, resulting in out-of-phase signals to the motors from each controller that prevented the motors from turning synchronously! After realigning both the magnets and hall-effect sensors, we noticed a much smoother operation.
One Wheel From Two 13 Feb 2022, 2:07 p.m. EST
Day 7: A great tragedy struck, we tested replacement board, which was broken from the start ;( and also fried the 2 sideboards from the initial parts list. ESD safety should not be taken lightly!