Mouse Treadmill with Encoder

Founding developers Jon Arnold and Steven Sawtelle

Add-ons for Mouse Treadmill with Encoder

Founding developers Jon Arnold and Steven Sawtelle

This treadmill was developed by engineers at the Janelia Research Campus of the Howard Hughes Medical Institute HHMI. Jon Arnold developed the treadmill and Steve Sawtelle contributed the encoder interface that generates the data. Originally developed for Shengjin Xu (Sternson lab) the treadmill was mostly used by the Lee lab. The treadmill is one of the many innovations of the HHMI Janelia Research Campus that are shared with scientists globally.

Low-friction treadmill with a very compact design. It is manually driven. A rotary encoder tracks belt movement. An encoder interface based on a teensy microcontroller reads the encoder and calculates speed and direction. Speed is updated every time it changes. If no changes are detected over a set time (typically 50 milliseconds) the speed is set to 0. Distance is also accumulated. The USB-serial connection sends distance and speed on every change. The analog output gives a voltage proportional to speed. With the sketch provided 100 mm/sec are 2.5V. These values can be changed in the sketch as you wish.


  • low-friction, manually (rodent) driven treadmill
  • low profile design fits under most microscopes
  • quadrature rotary encoder, decoded by a teensy interface
  • USB serial interface for speed and accumulated distance
  • 0-3.3V analog output of speed and direction
  • uses 5V USB power supply
  • Teflon surface for low-friction
  • easy to change and easy to clean polyester belt
  • connects easily to M6 or 1/4" breadboards

Calibration of speed, distance, and ouput voltage can be customized. The treadmill also functions without the encoder connected.


Jackson J, Karnani MM, Zemelman BV, Burdakov D, and Lee AK. (2018). Inhibitory control of prefrontal cortex by the claustrum. Neuron 99: 1029–1039.

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