
EyeLink Systems and Biosemi Integration
With a strong background in academic research, BioSemi offers a range of state-of-the-art equipment for the most demanding biopotential measurements. Integrating Biosemi hardware with EyeLink systems is very straightforward. Integration is achieved via TTL signalling to mark critical trial events and to perform basic control operations such as starting and stopping the EEG recording.
Experiment Builder and Biosemi Integration
Version 2.2 of SR Research Experiment Builder software has dedicated nodes that simplify integrating BioSemi EEG systems with EyeLink systems.
Dedicated Experiment Builder nodes allow users to:
- Start and Stop EEG recordings
- Use the BioSemi USB Trigger Interface
- Send event markers to mark stimuli and response onsets

EyeLink and Biosemi Integration Detail
- During task performance, the stimulus presentation software (e.g. E-Prime, Presentation, PsychToolBox, etc.) running on the Stimulus PC simultaneously sends TTL signals to the BioSemi equipment and messages into the Eye Tracking data via the ethernet link.
- The TTL signalling is typically achieved using the BioSemi USB Trigger Interface Cable.
- TTL signals can also be sent from the parallel port of the Display PC or Host PC. If neither computer has a parallel port then we can provide a USB to TTL device with excellent timing properties. Please contact sales@sr-research.com for details.
- The TTLs / Messages mark key trial events (such as stimulus onset / participant response etc), in both the EEG data and the eye tracking data, enabling synchronization of the two data streams at the analysis stage.
- Basic control of the BioSemi hardware can also be achieved, by configuring specific TTL values to start / stop recording.

If you have any questions regarding EyeLink-Biosemi integration, feel free to contact us. We’re always happy to help.