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by lstodd 3 days ago
about the same idea as nipkow disk

nowadays when people don't want to go the rotating led bar way, which requires very high density led strips (hundreds of ~200-400 mil smd leds) and the accordingly complex control circuitry (basically an FPGA per bar + high speed bus, etc), they do nipkow disk but with individual leds instead of holes. this way you can get away with tens of leds while still having a reasonable sized picture and not that much bandwidth to drive it.

edit: another, less sophisticated take is for example

https://hackaday.io/project/191947-rotating-led-display/deta...
1 comments
kitd 3 days ago
I mean if you squint hard enough, it's the same idea as a cathode ray tube. Each hole scans across the "screen" for the desired width, then the next hole down takes over, which does the same. Back in the day, you'd get an interrupt when the reset happened, and you could recalculate your sprite position before the next line got scanned.

Very cool seeing this implementation though. Congrats, OP!

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fanf2 3 days ago
It’s closer to John Logie Baird’s electromechanical televisor from the 1920s https://earlytelevision.org/baird_televisor.html which was the first practical implementation of a Nipkow disk
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lstodd 2 days ago
Yup. On the mid-tier you have this

https://www.youtube.com/watch?v=uoANiFHljGw

I actually have one of those laying around, burned out unfortunately (don't ask).

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