Mini Stepper Mechanism
Mechanical stepper mechanism in a small version optimized for use in shifting transmissions. Instructions available.
Having designed a robust 4-speed transmission that could be shifted instantly using a Control+ motor, and combined into a single 16-speed transmission, I have started to look for ways to use it with older motors. One way was to use a mechanical stepper I have developed previously, but it was large and didn’t fit this transmission too well. Instead, I have developed a smaller stepper optimized for this transmission.
The building instructions are available here: https://sariel.pl/downloads/
The purpose of the mechanism is to break continuous rotation into “steps” of 90 degrees each. When controlled remotely, with the right timing this makes it possible to rotate the output by just 90 degrees in one direction or the other, which is exactly what it takes to shift a transmission like the one I’ve developed by 1 speed. The version shown in the picture is the smallest possible version, with motor connected directly to the stepper, and thus working really fast, which may make shifting remotely difficult. It’s possible to gear the motor down to make it easier – the instructions and the video demonstrate an alternative version with a 3:1 gearing between the motor and the stepper.
Video:
