Eye Tracker

What kind of eye tracker do I need?

Tobii Eye Tracker 4C

Calibrating the eye tracker

Under the 'Eye Tracking' menu, make sure 'Control Mouse' is selected, and then select 'Calibrate'. Alternatively, use the voice commands in the eye control module.

Look at each dot until it disappears, and there should be 9 total dots. Exiting early could mean there is something environmentally wrong that is preventing the eye tracker itself from calibrating.

How do I click?

Click using voice commands in the mouse module. or by making a pop noise, pop noise module here.

How can I adjust the velocity setting (move cursor more or less with head movements)?

Adjusting the velocity can be done by modifying the eye_mouse.config.velocity values, e.g. below where horizontal=150, vertical=225:

from talon_plugins import eye_mouse
eye_mouse.config.velocity = eye_mouse.Point2d(150, 225)

Can I use eye tracking without voice?

Yes, some users will use foot pedals to click, or clickers on trackball or rollermouse.

Can the eye tracker be used with one eye or a lazy eye?

Yes! There are separate gaze targets for each eye. It's also possible to mask out one eye so the other isn't even considered.

Monitor Size

24" is the recommended size, but tobii will work with up to 27".

My cursor feels jittery.

Turn on the debug overlay using the voice command. and try increasing the zone1 radius. A larger zone1 radius means less jittery. The radius can be modified by editing a python file in /Applications/Talon.app/Contents/Resources/talon_plugins/eye_mouse.py. In that file, search for zone1 and edit the radius.

I'm looking at the same place, but the mouse is jumping around.

This probably means the eye tracking conditions are bad. Consider making adjustments to the following and run calibration again:

• Lighting - make sure your face is well lit. Low, back, or side lighting can all create poor results. Try opening or closing curtains, add a lamp behind our monitor, etc.
• Angle - make sure tracker is mounted on your monitor below eye level. If the angle is too extreme, the tracker won't be able to see your eyes.
• Distance - make sure you are the appropriate distance from the monitor and tracker.