2-wire control bus for ebikes

E-bike cable killer 2-wire control bus

See the whole article at my website: https://www.avdweb.nl/solar-bike/electronics/cable-killer

For my solar-powered bicycle, the Maxun One, I have developed the ebike cable killer. This is a 2-wire control bus for e-bikes. Since just 3 wires are needed for the entire control of an e-bike, very robust RC-model connectors can be used:

It has several functions:

• It gets rid of the rat's nest of cables coming out of the motor controller
  It can communicate to an LCD display or smartphone wirelessly.
  It supports all kind of bicycle electronics, such as torque sensor, temperature sensor, shift servo etc.

PCB


Wire reduction
Here is a view of the rat's nest of cables coming out of a motor controller:


Here's the new reduced cabling with the ebike cable killer:


2-wire control bus

To reduce the number of wires I have developed a current controlled bus, so-called “Cucobus”. It is a bus with the least number of wires possible, only two: GND and 5V.
Maximal 7 switches can be connected to the Cucobus. When a switch is pressed, the 5V is loaded with a resistor, see the circuit. The cable killer measures the current from the 5V and deduce from this which switches have been pressed. For safety reasons, no errors are allowed here. As a result, the development of the cucobus took a lot of time and is quite complicated. For example, compensation is made for the supply current of the Hall sensors. The bus is continuously calibrated and if a suspicious fault occurs, the system is shut down.
Two current controlled busses are needed, one for the electronics at the bicycle frame and one for the handle bar. Just a single 3 pole connector is needed for the control of an ebike.

Future development
The E-bike cable killer is very robust, I've used it at my solar bike for more then 10,000km without any errors. Still, a new improved version has to be made. But since I'm working on an important invention, I don't have time to required finish this project. I would like someone else to take over this project, I will help with that.
See the whole article at my website: https://www.avdweb.nl/solar-bike/electronics/cable-killer

That's a very interesting concept, and clearly you've put a lot of work into it! However, I would point out that there are other more mature solutions such as LIN (2 wire) and CAN (3 wire) available that would probably be better to implement. LIN is 2 wire and CAN is 3 wire because you really do need a ground return for each.

Yes I know about CAN. But then you have to place a complicated CAN bus PCB at every switch, such as the brake switch. https://www.avdweb.nl/solar-bike/mechanical-issues/brake-switch

But the LIN (2 wire) bus is very interesting, I'll look into it...