I've been tripping over my broken electric go kart in the garage for a few years now, I think it's time to rebuild it.
If I get chosen for the IoT on Wheels design challenge, I'll add some microprocessor control and monitoring.
The batteries are long dead, but the lights still work, and I think the motor controller can be saved with a few modifications.
This is how the whole thing started:
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Not much to look at, but it was free.
After cutting the frame and extending it to fit me and my son, adding some new wheels and axles, and rebuilding the steering with a good bearing.
Here it was after about $300 in parts and a couple of weeks of welding/cutting/hammering/screaming/painting:
The motor is an aircraft starter motor approx. 1Hp. I wired up lights and turn signals, here's the wiring diagram:
I'm currently reverse-engineering my own motor controller because I can't find the original schematics from 2009.
The controller is based on my 4000W MIDI-controlled Tesla coil HV IGBT driver circuit. The basic motor control gets input
from a linear variable resistor mounted on the throttle pedal, and converts that to a PWM signal to drive a 600A IGBT for the motor.
The brake switch is also used to disable the driver circuit.
The IGBT is housed in a solid aluminum box with a big heatsink on the back and a current shunt in series with the motor ground lead.
Here's a pic:
I found a paper copy of the system schematic, but not the controller schematic. The controller isn't very complicated, I'm running the controller from 2x12v sealed batteries,
regulating to +15V for IGBT gate drive and +5V for the rest, I'm using a TL491 for the PWM to a UC3708 Driver. I put a big 400A flyback diode on the IGBT for protection.
Here's a pic of the controller pcb:
I'll continue this blog as the project develops.