Elegant, functional mechanical models don’t need to be large. In their “LEGO Technic Micro Stepper Mechanism” video, Lego Technic Mastery demonstrates how to build a simple, manually-operated stepper motor that can attach to any Technic beam. This stepper machine has four 90° stops, allowing for precise quarter turns in both the clockwise and counter-clockwise direction.
At 0:56 in the video, Lego Technic Mastery provides a shot of all the parts needed for this mcahine plus step-by-step instructions. I followed the instructions and built my own “little stepper” with little difficulty (although I did break a LEGO rubber band in the process).
Check out Lego Technic Mastery’s YouTube channel, which includes an awesome pneumatic robot hand!