ArthroTrackball - A python package to control a spherical treadmill for walking arthropods

For years I have been interested in jumping spiders vision. However, testing these animals had many limitations, with the most prominent being the presentation of artificial stimuli at a known angle, but without impeding the spiders’ motion.

The use of spherical treadmill unlocked for me the possibility to test many hypothesis! In such a system, the animal is affixed ad placed onto a frictionless ball. The ball movement are registered and used to derive the intended motion of the animal. Shoutout to the excellent FicTrac software, which is what I mostly use to record the sphere rotations.

However, it is crucial to syncronize the video recording of the sphere together with the stimuli presentation. The control is further complicated by adding other devices, like a second camera or multiple monitors.

I have developed a python package leveraging multithreading and the internal clock of the computer to simultaneously record and present data, saving everything in a compressed format ready to be analyzed together.

Features:

• Recording from usb cameras, with timestamps from every frame as a list

• Displaying of visual stimuli (based on psychopy)

  • Including pre-programmed stimuli types (looming, translating, appearing)
  • support any number of monitors in any orientation (specified in a cartesian plane)

• Controlling serial devices:

  • Sphere tracker based on optic mice
  • Reward dispenser
  • LED based ring around the sphere

• holistic data logging and compressing into a single files, independently from the number of modules loaded

Dependencies:

State of development

I plan to publish the first version of package on github by the end 2024. At the current version, the software is functional but lacks documentation.