Overview #

Click to view CAD model

This is the documentation for building and using a retractable lever. This project was developed in the Karpova Lab at HHMI’s Janelia Research Campus for use in rodent behavioral experiments.

Features #

  • Extends and retracts depending on input signal
  • Outputs signal when lever is pressed or released
  • pyControl compatible
  • Durable - faceplate and lever are made of aluminum
  • Fast - 180ms to extend or retract
  • Open - all files are available on GitHub and can be modified to meet custom needs

The servo and lever mount interface using a pin and slot mechanism. The lever rotates about two spring plungers.

Servo arm rotation is translated into linear movement of a carriage along a guide rail

The lever begins retracted


As the stage extends, the limit switch arm rolls along the lever surface.


Pressing the lever front lifts the back and actuates the limit switch.


These docs are built with Hugo . A fork of Hugo Book is used for the theme.