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.
Scanwheel is a drum style mechanical television you can build yourself
11–19 of 19 posts
Re: Scanwheel is a drum style mechanical television you can build yourself
#12How 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…
Re: Scanwheel is a drum style mechanical television you can build yourself
#13eat it hdmi
Re: Scanwheel is a drum style mechanical television you can build yourself
#14about 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…
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!
Re: Scanwheel is a drum style mechanical television you can build yourself
#15Re: Scanwheel is a drum style mechanical television you can build yourself
#16I 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.
Re: Scanwheel is a drum style mechanical television you can build yourself
#17about 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…
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
Re: Scanwheel is a drum style mechanical television you can build yourself
#18How 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…
Re: Scanwheel is a drum style mechanical television you can build yourself
#19Earlier quoted context omitted.
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).