Scanwheel is a drum style mechanical television you can build yourself | Hacker News Reader

Scanwheel is a drum style mechanical television you can build yourself

github.com

69 pointstobr17 comments

I was especially surprised when the other LEDs joined into the action, to allow multiple separate video streams... it took a minute for me to grok how it was done.

There's nothing stopping this from being a 360 degree display, if there's enough compute to feed the LEDs the right bits.

If the Stepper motors get hard to source, you could always rip apart a 5v BLDC box fan, and feed the motor 3 phase signals.

Unfortunately the video link points to https://example.com/docs

https://youtu.be/41b8fw3_wP8

From git history on the readme.md

Also, the second picture is a video link with the correct URL.

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...

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!

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

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).

It's stunning. The video speaks for itself. Please scale this up, like way up back of a truckbed size. This would be delightful to see spinning and running IRL.

Then get a grant and make one as wide as a city street

How do you get the flashing LED synced up to the spinning pinholes? Maybe the motor provides some positioning feedback so you just have to line it up once…

https://en.wikipedia.org/wiki/Stepper_motor

I can see this being applied to hubcaps in the future.

Okay, that is genuinely amazing.

Love it, thank you for sharing and for being inspiring :-)

Absolutely fantastic!

The video URL doesn't seem to be correct, through. ;)

> Avoid use in operations.

Oops

The video is also awesome!

I had to lol at the doom scene.

eat it hdmi

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