So I have been playing around with this thing, and it has been doing pretty well, but it is definitely time to think about a permanent steering system. The remote I have been using has been great for proof of concept, but if you have ever tried to drive something with a remote while you were sitting on it you know it is a good way to fall off. With the lack of engine, it is nice to be able to get in from the front, but when you are driving you really need something to hold on to. I’ve been thinking of a flip down bar that allows both the passenger and driver to hold on, then flip up so that people can get out. See photo.

I started thinking about what is the most intuitive way to drive a vehicle with differential drive steering like this. A joystick makes sense, but doesn’t really allow one to hold on well when you are going over rough terrain. I decided I wanted to try out dual twist throttles. Like what you have as a motorcycle accelerator. Unfortunately normal motorcycle parts wouldn’t work here because I want a throttle that springs to the center position to allow for movement in both forward and reverse. I decided to custom make a throttle set up that would be in line with the grab bar in the front. I also decided to put an lcd in the middle to give a live display of battery voltage, motor current, solar power coming in and maybe a few other things.

The throttle assembly is all steel. The grips are a slightly larger diameter pipe that slides nicely over the grab bar. The throttles turn a pair of 10k pots which are then read by the atmega328p which will look at this plus the readings from a pair of allegro ACS758 200a hall effect current sensors to determine the pwm to the motor controller.

The display is just a simple 32 character LCD running with another Arduino pro mini. I will include several buttons to change some settings and also control horn and lights.

Probably the hardest part was figuring out the spring return to center. At the moment I am using strips of rubber from an old truck inter-tube. It gives a nice strong feel.

I am looking forward to mounting this thing to try it out on the vehicle.