DIY ergonomic thumb switch for e-bike throttle control and electronic gear-shifting
Introduction
Efficient speed control is crucial for a comfortable and enjoyable e-bike riding experience. This article presents an innovative solution for speed control through an ergonomically designed thumb throttle switch.
Electronic gear-shifting
This article is about speed control, but everything also applies for electronic gear-shifting.
Benefits of the thumb throttle switch
The thumb throttle switch allows riders to easily control the speed by pressing the up or down buttons with their thumb. This method is rarely used in e-bikes, but it has proven to work very effectively.
Because the switch is often pressed, it is important that it can be used with as little effort as possible, preventing thumb strain caused by excessive force or movement. The normally used thumb switches are not suitable for this purpose as they are much too heavy to press and not ergonomic enough.
Features of the thumb throttle switch
- Low force operation: The switch is designed to require minimal force, preventing thumb fatigue. The buttons are highly responsive, allowing riders to adjust the speed effortlessly with gentle presses.
- Ergonomics: The buttons enable riders to control the speed with minimal movement of their thumb.
- No extra space is needed on the handlebar: Normally, such a throttle is mounted between the grip and the brake lever which increases the distance between them, see for instance the Bionx throttle or the Shimano switch unit SW EM800 L. That's why I made a throttle that is mounted on top of the brake lever clamp so that no extra space is needed on the handlebar.
Ergonomic space saving ebike thumb throttle switchErgonomic space saving ebike thumb throttle switch
Bionx thumb throttle
Shimano switch unit SW EM800 L
Electrical connection to the motor controller
My thumb throttle only contains two switches and doesn’t have an analog output as the commonly used Hall sensor throttles:
Analog e-bike Hall sensor thumb throttle
You can connect the thumb throttle to motor controllers with a throttle up/down input.
I use the thumb throttle on my Maxun One solarbike and it is connected to a self-developed two-wire bus.
Design files
DIY thumb throttle switch
You can download the files from GitHub here.
Sensitive tactile switches
Since you have to press the buttons very often, very sensitive tactile switches are used so that you only have to press very lightly: the PanasonicEVQ-P6LB55 tactile switches are also watertight (IP68)
A lot of attention has been paid to making the design as simple as possible, it consists of a PCB and two 3D printed plastic parts.
I had the parts printed with Selective Laser Sintering (SLS) in PA12.
Panasonic watertight EVQ-P6LB55 tactile switches
Ergonomic ebike thumb throttle
E-bike speed throttle wiring
PCB
The thickness of the PCB is 0.5mm
Thumb throttle switch circuit v8
Thumb throttle PCB v8
Redundant speed-up switch
The speed up and down tactile switches are very sensitive but therefore also quite vulnerable. To ensure that you can continue cycling with a defective speed up switch, a redundant speed-up switch has been fitted in the middle, which you can operate by removing the cover.
Redundant speed up switch
Assembly
The button must be able to move up and down. That's why I glued it with Kafuter K-705 Tansparent RTV Silicone Rubber Sealant.
I glued the button to the brake handle with PU glue.
Motor controllers with throttle up-down input
For suitable controllers, look at Groetech (Universalcontrollern).
Freely available
My solution, described here, enhances the experience of riding e-bikes. That's why I'm making my ergonomic thumb switch freely available to anyone who wishes to use it.
Links
Guide to Hall Sensor Throttle operation, testing, and modification.