Scanwheel is a drum style mechanical television you can build yourself

Posted by tobr 2 days ago

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Comments

Comment by mikewarot 1 day ago

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.

Comment by iefbr14 2 days ago

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

Comment by portalcell 2 days ago

https://youtu.be/41b8fw3_wP8

From git history on the readme.md

Comment by jolmg 2 days ago

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

Comment by lstodd 2 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...

Comment by kitd 2 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!

Comment by fanf2 1 day 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

Comment by lstodd 1 day 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).

Comment by bensmoif 2 days ago

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

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Comment by pbronez 2 days ago

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…

Comment by josh-wrale 2 days ago

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

Comment by CrzyLngPwd 2 days ago

Okay, that is genuinely amazing.

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

Comment by lagrange77 2 days ago

Absolutely fantastic!

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

Comment by mysterydip 2 days ago

> Avoid use in operations.

Oops

Comment by lagrange77 2 days ago

The video is also awesome!

I had to lol at the doom scene.

Comment by effnorwood 2 days ago

eat it hdmi