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Punched card/tape readers that work using either electrical contact through the holes or light sensors just as this one are intuitive for me, but I have never s
by 7373737373 3y ago
Punched card/tape readers that work using either electrical contact through the holes or light sensors just as this one are intuitive for me, but I have never seen an explanation of how entirely mechanical readers work Edit: found this: "Paradise Mill How The Jacquard Mechanism Works" https://www.youtube.com/watch?v=x_ijmjx7Xys https://www.youtube.com/watch?v=x_ijmjx7Xys and "How was it Made? Jacquard weaving": https://www.youtube.com/watch?v=K6NgMNvK52A https://www.youtube.com/watch?v=K6NgMNvK52A
- klyrs 3y agoWhile I've never seen a thorough explanation either, it seems intuitive enough to me. A sprung pin will fall through the hole of a punchcard, and will not if there is no hole. The motion of that pin can be amplified through clockwork to drive a greater mechanism. Note particularly the escapement: https://ciechanow.ski/mechanical-watch/ https://ciechanow.ski/mechanical-watch/
- 7373737373 3y agoAt least for tape, that must have caused quite a bit of wear Non-reusable/limited use source code :D
- klyrs 3y agoIf you do it right, it shouldn't cause significant wear to the punched cards. You'd want to move the cards with the pins up, and then drop the pins (read head) after moving them. Each pin wouldn't need to exert much force on the paper, nor should the pins be dragged in and out of the paper hole. From everything I've read, the card sets were used many times -- at least one mention on the wikipedia article of a set of cards being used over 100 times. Oh, and wikipedia has a nice figure from, I believe, Jacquard's patent. https://en.wikipedia.org/wiki/Jacquard_machine#/media/File:Telaio_Jacquard_1849.jpg https://en.wikipedia.org/wiki/Jacquard_machine#/media/File:T...