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Intro

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:

Robust RC-model connectors used for an ebike
Robust RC-model connectors used for an ebike

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

E bike cable killer PCB
E bike cable killer PCB v0

E bike cable killer PCB
E bike cable killer PCB v0

Wire reduction

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

Rat's nest of cables coming out of a motor controller
Rat's nest of cables coming out of a motor controller

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

E bike cable wire reduction
E bike cable wire reduction

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:

E-bike cable killer 2-wire control bus
E-bike cable killer 2-wire control bus


The E-bike cable killer works for all types of motor controllers and is small enough to fit into the small KU63. It consists of two PCB’s, the main PCB is built into the motor controller, the front PCB replaces the front plate thereof.

E bike cable killer inside KU63
E bike cable killer inside KU63

E bike cable killer inside KU63
E bike cable killer inside KU63

Circuit description

This is the old circuit version v0, used in the Maxun One solar bike for many years now:

E bike cable killer circuit v0
E bike cable killer circuit v0

Here's the newer circuit v1 that is not finished yet:

E bike cable killer circuit v1
E bike cable killer circuit v1

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.

These are the main improvements:

  • The 5V switching power supply is now synchronous
  • The SAMD51 is replaced by an STM32 controller

Fora

Control of additional components

The cable killer has two connectors, JM4 and JM5, for the control of extra components such as lights, torque sensor, temperature sensor, shift servo etc:

Cable Killer maximum wiring

2-wire control bus development

Here are photos that give an insight into how the Cucobus works:

Current controlled bus development
Current controlled bus development

Current controlled bus development
Current controlled bus development

Do you have any comments about the website? Please let me know.