CIBERTEC CEV-1 Visual Event Counter measures the time that an event appears on the screen. It has a sensor which is placed in a corner of the monitor detects the start and end time of the visual stimulus. The time is displayed on a screen on the computer and can be reset to start a new one. 

The CEV-1 has an output that can be connected directly to a registration system to synchronize the displayed with the rest of recorded signals such as EDA electrodermal response, pulse, ECG....

When a stimulus presentation software is used on a PC, it has mechanisms to synchronize the software with record systems, but there is the problem of inaccuracy introduced by the operating system of PC, graphics card and the monitor when synchronize the exact time of stimulus presentation and duration. The CEV-1 eliminates this vagueness and allows a real synchronization in the system registry.