Electrophysiological experiments rely on precise timing of event or stimulus presentation to timely relate the recorded signals with stimulation instances for processing and analysis. The timing of the stimulus presentation can vary from system to system depending on hardware (e.g., computer specifications, screen refresh rates, etc.) and software configurations (e.g., level of system control, drivers, scheduling, network characteristics, etc.). To reliably process experiment data, this timing of events needs to be fully characterized or controlled using specialized accessories traditionally referred to as Trigger Boxes. This project entails the design, construction and validation of a stimulus-event trigger box intended to be used for synchronization of events in EEG experiments. In Phase 1, a trigger box compatible with participant push-button events, screen image flip events and audio events, was designed, built, and validated. In Phase 2, a subsequent addition to integrate lab-streaming-layer (LSL) synchronization will be developed.