Light pen

It allows the user to point to displayed objects or draw on the screen in a similar way to a touchscreen but with greater positional accuracy.

A light pen detects changes in brightness of nearby screen pixels when scanned by cathode-ray tube electron beam and communicates the timing of this event to the computer.

The first nonlinear editor, the CMX 600 was controlled by a light pen, where operator clicked symbols superimposed on edited footage.

Light pen usage was expanded in the early 1980s to music workstations such as the Fairlight CMI and personal computers such as the BBC Micro and Holborn 9100.

[citation needed] Light pen was also perceived as working well only on displays with low persistence, which tend to flicker.