William Gardner | Electro-Mechanical Engineer
Electrical Overview
The main performance requirements of this project were to introduce a new hands-free control system and a user-friendly interface.
The performance requirements were executed using force-sensitive resistors, a touchscreen display, and two Arduino microcontrollers (Nano Every and Mega 2560). The Nano Every microcontroller takes the difference in applied pressure to the sensors, converts the analog value into a PPM signal, and outputs it to the motor controller.
The Arduino Mega 2560 communicates through UART with the motor controller, Nano Every, and touchscreen display. The Mega 2560 reads raw telemetry from the motor controller, such as battery voltage, motor current draw, and the number of pulses from the hall effect sensors. Telemetry is then converted and output to the display. The touchscreen display also allows users to change settings such as acceleration and deceleration gains, sensor calibration offsets, and more. The saved settings are then used to modify the PPM signal sent to the motor control.
After multiple prototypes, extensive testing, and troubleshooting, the schematic was designed using KiCAD. The PCB was created as a shield that plugs directly into the Mega 2560 to save space and reduce the chance of distorted signals from electrical noise.
Design Solution
My team and I set out to design an electric skateboard that could outperform industry-leading companies, incorporate a hands-free control system, and a user-friendly interface while maintaining a thin, elegant design. The slim design was achieved using two fabrics, 2 x 2 twill weave carbon fiber, and prepreg unidirectional carbon fabric. The deck design took several weeks before reaching a final design due to running Solidworks structural analysis simulations and designing separate molds for the top face, bottom face, electronic box, and lid. Once the four molded parts were fused, the excess material was removed using a router guided by plexiglass stencils. The deck proved challenging, considering budget, structural integrity, and time constraints, but it resulted in a design that met project demands and a rewarding feeling of accomplishment.
Safety Features
A few safety protocols have been implemented to ensure the safety of the rider and their surroundings. First is the Fall-Off protocol, which detects if the user has fallen off the board. In this case, the board will automatically apply the brakes until it brings the board to a stop. Second, LED lights have been added to the front and back of the board to help drivers spot them at night. The Brake light gets brighter when the user slows down
Performance Requirements
- Our goal was to push the boundaries of electric skateboards. Not only did this mean going faster and further than other brands, but introduce a new hands-free control system and a user interface that anyone could use.
Top Speed - 35 mph
The range on a single charge – 22 miles
Hill Climb – 23 percent grade