Pen plotters: not just output devices (2016)

Re:Pen plotters: not just output devices (2016) by at_a_remove on Saturday May 01, 2021 @03:07PM (#27008907)

Around 1991 or so, I built an extraordinarily slow and deeply terrible scanner out of a plotter which had a simple fiber optical sensor instead of a pen. It was one of those "see what you can do with this stuff" projects that got thrown at me and I just coded this up with a data acquisition board and some flavor of BASIC. Supposedly about 1000 dpi.

I eventually came up with routines to speed up the scanning (left to right, move up, right to left, move up ...) and even hit upon using the "judder" from the repositioning of the pen to, properly timed, grab a point. This saved me from having to fully stop, I could just vibrate the pen forward. This ... probably did not do much for the lifetime of the plotter.

Man, that was a hot mess.

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Re:Pen plotters: not just output devices (2016) by neilv on Saturday May 01, 2021 @04:41PM (#27009628)

I think that's an improvement upon Forrest M. Mims III's plotter scanner. (He's the one who hand-drew some of the books at Radio Shack, like Getting Started in Electronics, and the 555 timer application notes circuits.) IIRC, for an article for Computers & Electronics magazine, he rigged up a flatbed X-Y plotter with an optical sensor (maybe one of the cadium sulfide photoresistors that RS sold?), and the resolution was very low, but it was pretty inspiring to kids. (It also gave you another reason to crave a plotter, which you now saw was really a robot module.)

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Re:Pen plotters: not just output devices (2016) by at_a_remove on Sunday May 02, 2021 @01:56AM (#27012664)

Yeah, I used to have all of the Mims books from RadioShack. They were fantastic.

I recently found a partial printout of my "software," so I am looking at code three decades old. And it still had my style.

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