An OpenSesame plug-in for sending stimulus synchronization triggers through the parallel port to data acquisition systems.
Copyright, 2022, Bob Rosbag
Contributions: Code is based on the work of Per Sederberg. Debugged and polished by Edwin Dalmaijer.
In EEG/ERP studies it is common to send triggers to mark the timestamp for significant events (e.g., the onset of a trial, presentation of a particular stimulus, etc.). Triggers are typically bytes that are sent via the parallel port to data acquisition systems.
The plug-in has an init item which should be placed at the beginning of an experiment and a trigger item for initiating triggers:
- Dummy mode for testing experiments.
- Port address for Windows: hexadecimal (0x378), for Linux: port number (0 in /dev/parport0).
- Value is a positive integer between 1-255 and specifies the trigger byte.
- Enable duration option to enable the duration parameter.
- Duration is the duration in ms.
Linux and Windows are supported (possible also OSX, not tested). For Windows the DLPortIO.dll driver is used to access the parallel port. No need for driver installation.
Documentation: http://osdoc.cogsci.nl/devices/triggers/
The Parallel Port Trigger plug-in is distributed under the terms of the GNU General Public License 3. The full license should be included in the file COPYING, or can be obtained from
This plug-in contains works of others.
Installation instructions and documentation on OpenSesame are available on the documentation website: