Electric Accelerator, Electric Brakes (applies to all E-trikes)
To facilitate acceleration and braking we will use right hand grip brake lever from the conversion kit to control the front brake. This grip has a brake magnetic switch wire set to signal motor inhibit. The right hand grip has an acceleration potentiometer with 3 wires to pass speed control info to the controller. Instead of using the other supplied hand grip we will add a second accelerator grip to the left side and repurpose it as an electric brake for the rear wheels.
To accelerate, you turn the grip back towards you. to brake, you pull the right brake lever for the front wheel and rotate the left grip forward away from you to brake the back wheels. This is kinda the reverse of a normal bike break which has left control front and right controlling rear. The 3 Accelerate throttle wires go to the back controller. The 2 right brake wires, and 3 brake throttle wires go to the front controller.
We will only have partial electronic braking for two reasons. Firstly, without manufacturing an electric caliper for disc or rim brakes or machining an electric drum piston/shoes, we can't apply the pads to perform the stopping. This means while we can run a servo to electrically move an actuator, the actuator has to still pull a cable to the caliper unit. As such the best we can do is limit cable lengths to be shorter, precisely apply both rear brakes in one motion, trigger motor stop from either brake handle, and attenuate the brake pressure by the amount of brake handle movement.
A second reason for not having full electric brakes is that if we loose power for any reason, we still need some way to stop the trike even if not efficiently. So for this second reason, we must retain the front brake as cable driven to either a rim brake or disc brake system. The right hand grip will be changed to a twist throttle as per normal. It's brake lever will be changed to one with a built in micro switch or hall sensor or magnetic reed switch so it can notify the system to cut motor power. But this handle will have a brake cable going to the caliper of the front wheel. It's wiring must pass to the lighting control unit along with the accelerator wiring.
A PWM control system takes the amount of pressure to apply and sends a signal to the servo to push a lever which in turn pulls two cables to activate the brakes.