Coaxial Commutators#

Active, near-zero torque commutators prevent tether twisting during freely moving recordings with headstages and/or miniscopes. This page provides a very brief overview of the commutators; for a more extensive walkthrough, please follow the documentation link for Commutators.

Design Repository:

open-ephys/commutators

Compatibility:

All coaxial headstags (e.g. Headstage-64, Neuropixels-2.0e Headstage, Miniscopes)

Documentation:

https://open-ephys.github.io/commutator-docs/index.html

Overview#

../../_images/commutator_front.jpg

ONIX Single Channel Commutator#

ONIX uses an active commutator to prevents tether twisting during freely moving recordings. A inertial measurement unit (IMU) on the headstage or miniscope sends orientation data to the host computer. Because the real-time orientation of the animal is known, software can be used to send commands to the commutator via its USB interface, and the motor in the commutator will turn when the animal does. A high-quality radio-frequency rotary joint inside the commutator maintains electrical connectivity for both power and high-frequency data signals between the tether leading to the headstage and the coaxial cable leading to the PCIe host board while turning.

Features#

  • High bandwidth link up to 18 GHz

  • Optical table & 80/20 rail mountable

  • Remote control using JSON-encoded commands

  • Manual control using capacitive sense buttons

  • Indication LED (can be turned off)

  • Advanced stepper driver (TMC2130)

    • Voltage-controlled for silent operation

    • Precise motion using step interpolation (256 uSteps/step)

  • USB powered and controlled

    • Internal super-capacitor circuitry prevents loading the USB bus during motion