Odd Inputs And Peculiar Peripherals: Employing A Commodore Light Pen On A Contemporary(ish) Laptop or computer

If you labored with computer systems back in the 1970s, there’s a superior chance you made use of a gentle pen at some place: a simple input product that you’d level at the CRT monitor to highlight textual content, pick menu alternatives or manipulate graphic objects. While ubiquitous in those people times, the light-weight pen shed the battle for ergonomics to the humble mouse and was all but extinct by the late 1980s. Touchscreen styluses carry out a identical functionality currently, but touching the screen someway doesn’t feel the same as just pointing at it.

We therefore applaud [Maciej Witkowiak]’s attempts to bring the gentle pen into the 21st century by constructing a USB interface for a Commodore 64/128 light pen. At its coronary heart is an Arduino Micro Professional that implements the USB HID protocol to talk with any fashionable computer system. It connects to the common gentle pen as nicely as to the computer’s analog display screen sign and uses these to compute the hold off concerning the video synchronization pulses and the light pen’s output. The sync pulses are extracted from the online video sign by an LM1881, a sync separator chip that will be familiar to any individual who’s worked with analog video clip indicators.

The Arduino calculates the mild pen’s situation dependent on the calculated timing intervals and studies it to the computer, working with the absolute positioning method which is also utilized by items like drawing pads. [Maciej] demonstrates his program in the movie embedded under, in which he makes use of it to function the menus on an X window process. A good achievements then, whilst there is just one catch: gentle pens only perform on CRT displays, so you’ll need to have to drag one of all those big glass beasts out of storage if you want to test this yourself.

We have showcased the Commodore mild pen in advance of in this odd gaming input gadget. A similar machine constructed with a discrete LED matrix is a good illustration of the light-weight pen’s functioning basic principle.

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