An Electronic Bicycle Shifter

Jesse DeWald, of DeWald designs, describes himself as an engineer, educator, and problem solver. He’s also a rather avid bicycle rider. This interest and his talents allows him – possibly compels him – to upgrade his bikes when he sees the need.

In the process of 3D printing bar-end shifters for his rig, he found that prototyping took quite a bit of time and patience. He thus began to explore a benchtop actuator to help automate and measure the shifting process. Taking this a few steps further, such an actuator could be mounted on the bike itself, creating an electronic shifter.

Of course, while the idea may make sense, one might say that the magic is in the execution. DeWald outlines his thinking and process in his shifter project write-up, including a rather interesting discussion about how spring balancers and cables work, and the relative benefits of using a stepper versus a servo.

For this build, he was able to balance forces nicely so that a stepper can hold shift positions without having power applied all the time. This motor setup, along with the use of an Arduino Pro Mini – with the onboard regulator desoldered – as the heart of the controller, makes it very efficient. It can last in standby for three months, or shift 10,000+ times before needing a battery charge.

Code for the shifter rig can be found on GitHub, and the mechanical design is available for download in STL and Solidworks formats for your perusal.