A custom electric longboard!
This was my first proper CAD project, and I learned a ton while working on it: about motors, transmissions, machining, as well as basic firmware development.
- single reduction drivetrain powered by two 270Kv brushless outrunners
- 6 mile range & 22mph top speed, 5Ah 6S LiCoO2 battery
- CNC-milled motor mounts, waterjetted electronics mounting plate/heatsink
- 3D printed electronics enclosure
- eight individually addressable RGB status LEDs (all purple in picture)
- on-board 90W CC/CV battery charging circuit, powered by laptop AC adapter
Design was done in Autodesk Inventor (mechanical) and Altium Designer (PCBs).
A custom battery management system was designed to handle safety, charging, and cell balancing. It’s built around an LTC6803 battery monitor IC and an STM32F303 microcontroller.
- overvoltage, undervoltage, and overtemperature protection
- bidirectional current monitoring for overcurrent protection and SoC estimation
- boost converter for CC/CV charging high voltage packs from a standard laptop adapter
- 100mA passive cell balancing
- UART, I2C, and CAN communication ports
- WS2812 addressable LED support
- 1.9in x 2.9in footprint
A custom wireless remote charges over USB, and contains a 900mAh lithium battery for a ~36hr runtime per charge.
The electronics are built around an ATmega32u4 MCU and an nRF24L01+ 2.4Ghz wireless transciever IC.
ABS + Delrin drive pulleys:
Motor mount fixturing, machining: