Electric Bobby Car Hoverboard Upgrade

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Bobby car hoverboard upgrade bigbobbycar.jpg

This project puts four 350W hoverboard motors in a Big Bobby Car toy vehicle, to give it independent four wheel drive and a top speed of 29km/h with turbo activated. All controlled by two potentiometer triggers on the steering wheel.


Hoverboard left platform.jpg
  • Project start: January 2019
  • Controller: 2x Hoverboard main boards - 2015 date
    • MCU: STM32F103 72MHz ARM Cortex-M3 core
    • Flasher: ST-Link V2 Programming Unit clone
  • Motors: 4x direct drive 3-phase brushless electric wheel hub motors (BLDC) with hall effect sensors, 350W nom., 800W peak
    • Continuous Current(A): 1 to 25A
  • Tire type: non-pneumatic rubber tire, road pattern
  • Tire size: 7-inch / 170 mm
  • Battery: Lithium-ion rechargeable 18650-cells, 10S2P 36V 4400mAh 158.4Wh pack with XT60 connector
    • Upgrade: Controller can handle 13S (48V), 12S battery upgrade easiest
  • Charger: Lithium-ion charger 42V 2A 3-pin connector with built-in fan
    • Upgrade: External charger for anything else
  • Internal connectors:
    • PCB headers: JST B4B-XH-A 2.54mm pitch
    • Cable connectors: JST SM 4-pin and 5-pin 2.54mm pitch
  • Vehicle base type: BIG New Bobby-Car Red - note that it's the BIG version, easier to put your legs over the front wheel
    • Vehicle upgrade: Small cussion to improve seating comfort
  • Dimensions assembled: L57 x W30 x H39 cm
  • Original load-bearing: 50 kg max. - exceeded 150% 🤭

Control inputs

The hacked firmware supports a quite a few different types of control types, either partially or fully emplemented:

  1. ADC Analog voltage input via potentiometer - safety pull-down resistors on ADC1 and ADC2 recommended, high frequency filter to smoothen out the voltage
  2. I2C Nintendo Nunchuck official remote - I2C pull-ups required on SDA and SCL
  3. UART Serial control via another MCU or directly via terminal
  4. PPM Remote control via R/C radio


A rough overview of the components in the system.

Bobby car hoverboard upgrade overview.png



Schematic and pin-out of the hoverboard connections, by NiklasFauth. Pulled from the full schematic.

Hoverboard main schematic.png

Illustration courtesy NiklasFauth.

Hoverboard pinouts main board.png

STM32F103 MCU pin-out:

Hoverboard pinouts STM32F103.png

Throttle filter and connection board

This is a PCB I designed to break out the ADC/UART/PPM/I2C signals to make it easier to finish the build. It has master and slave throttle splitting, where one driver board can be turned off without interfereing with the other - allows for 2x2 front/rear or 4x4 drive!

It also adds filtering to the analog signals for voltage/potentiometer based throttle and pull-ups to the I2C-lanes for Nunchuck-throttle. All configurable via solder-jumpers for quick setup/change.

Inspired by the Jan Henrik break-out boards.

Bobbycar hoverboard throttle breakout schematic.png

Bobbycar hoverboard throttle breakout pcb top.png Bobbycar hoverboard throttle breakout pcb bottom.png