SSVEP Speller

SSVEP Speller is a hands-free keyboard you operate by looking. Each key flickers at its own frequency; when you focus your gaze on one, your visual cortex produces a matching response that the app decodes into a keystroke. It is built as an accessibility and research tool — a practical demonstration of steady-state visual evoked potentials (SSVEP) on open hardware.

It is open source and early-stage. Frequencies, layout and decoding parameters are all adjustable, which makes it a useful starting point for students and researchers as much as for everyday hands-free input.

Features

• Flicker keyboard with a configurable grid of frequency-tagged keys.
• Live decoder confidence so you can see selections forming before they commit.
• Adjustable dwell time to trade speed against accuracy for each user.
• Open and hackable — tweak frequencies, layouts and the classifier in code.

How it works

Every key on the grid flickers at a distinct frequency. When you look at a key, your occipital EEG picks up power at that exact frequency and its harmonics. The decoder runs a canonical correlation analysis against each candidate frequency a few times per second and selects the key whose signal matches best once it clears a confidence threshold. Because the response is driven by where you look, very little training is required to start typing.