But Why

The BeerKart

I happened upon a hoverboard in a junkyard one day. Knowing that at some point in the past I had read online that someone had managed to hack the hoverboard firmware to repurpose the motors and driver board for other applications, I went ahead and gambled on it.

It was basically working, except for its completely depleted battery. Hooked up to a 36v power supply, it powered up and all seemed ok.

Software

Following a guide posted by Emanuel Feru, I managed to re-flash the firmware to enable a 2 axis joystick input. This is an excellent guide and it contains everything you need to know and do.

I made some adjustments to the code for my use case and you can find it here.

Hardware

The most important criteria was to keep everything inside the beer crate as much as possible. This is what I came up with:

Basically, the mounting brackets for the motor shafts were cut off from the rest of the aluminium casting of the hoverboard and bolted to a welded structure designed to fit into the crate. After that, mounting the driver board, button brackets and battery was just a matter of rivnuts and cable ties.

The crate has some protuberances on the inside which rubbed against the tires, so those had to be grinded off, but other than that, the crate has no changes made to it.

Bolted on a plywood seat and a fake (for now) headlight and voila:

Conclusion

There are some issues that still need to be addressed.

The biggest is that because all the wheels are so close together, it’s pretty unstable. I really had to dial the max speed and acceleration values down to keep it safe. Also the very stiff steel structure and stiff ‘tires’ make it lose traction if the surface you are riding on is bumpy. In effect, if one wheel is in a slight depression on the road, it just spins freely because there is no suspension or flex in the structure.

Another issue is that currently the joystick that is used to input speed and direction is a pair of middle resting potentiometers typical for a joystick module. What this means is that the input to stop the cart from turning or moving is half of the ADC value the board can measure. Therefore, if the driver falls off, but holds on to the joystick and the connection breaks, the BeerKart will hurtle off into the distance looking for the most expensive car it can find. And let me tell you, it does a great job finding expensive cars. The last time it happened it was an Audi.

Thanks for reading!

Dima riding the BeerKart