One Wheel From Two

Created on 19 Oct 2021

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

Turned a cheap hoverboard into a One Wheel by reconfiguring parts and machining new ones. Its so slow you can't possibly get hurt! Will include some speed and range mods for those with a bigger budget hehe ;)

@apenney

Alby Penney

@dbarajas

David Barajas

Part Cost Quantity Total
The hoverboard $155.00 1 $155.00
700W Hoverboard with 8.5 in wheels to be converted into a one wheel (from Alibaba = forsure legit!)
The Foot Sensor $4.95 1 $4.95
Flexible resistive velostat sensor for foot control
The Tire $29.15 1 $29.15
13x6.5-6 Tire for drag-racing lawnmowers
The Tube $11.99 1 $11.99
Inner tube for the tire to ensure a smooth ride
The Backup Wheels $3.60 2 $7.20
Casters for the front to mitigate nose-dive accidents (which will never happen of course)
The Frame $28.03 1 $28.03
5 feet of 1"x2" OD 6061 Aluminum U-channel
The power $4.95 1 $4.95
30V/10A Digital voltmeter/ampmeter to display battery pack voltage and current draw
The Grip $8.99 1 $8.99
Grip Tape for traction
Project Totals: 9 $250.26
Track 1 Base Budget: $250.00
Preferred Vendor Budget Bonus: $0.00
Remaining Budget: $-0.26
Alby Penney 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.
Alby Penney 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.
Alby Penney 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.
Alby Penney 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.
Alby Penney 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.
Alby Penney 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).
Alby Penney 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.
Alby Penney 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!