- #1
NTL2009
- 623
- 384
I recently re-watched this video:
And I wondered, how are +5000 LEDs addressed/controlled? At 600 x600 DPI and an 8.5"x11" printing area, you need ~ 5120 LEDs across and 6600 scans. At 20 ppm, the scans would need to be less than 3 seconds total ( need to allow time for fusing, etc), so ~ 0.45 ms to "load" 5120 LEDs.
I'm thinking shift registers? One long register would be ~ 87 ns per LED, or ~ 11.377 MHz clock? I'm not sure that speed would be practical across that large an area or not, but it's far less than motherboard speeds. Maybe several (16?) in parallel. With 16 (a convenient digital hardware and software number), the shift registers would only need to be 320 deep, so 1.4 us per LED, or ~ 711 KHz clock? That speed may be more fault tolerant and/or cheaper to implement?
Or a different approach? It just seems like shift registers would be the simplest layout for such a small space (1:1 output with the LEDs, no matrix wiring).
-TIA
And I wondered, how are +5000 LEDs addressed/controlled? At 600 x600 DPI and an 8.5"x11" printing area, you need ~ 5120 LEDs across and 6600 scans. At 20 ppm, the scans would need to be less than 3 seconds total ( need to allow time for fusing, etc), so ~ 0.45 ms to "load" 5120 LEDs.
I'm thinking shift registers? One long register would be ~ 87 ns per LED, or ~ 11.377 MHz clock? I'm not sure that speed would be practical across that large an area or not, but it's far less than motherboard speeds. Maybe several (16?) in parallel. With 16 (a convenient digital hardware and software number), the shift registers would only need to be 320 deep, so 1.4 us per LED, or ~ 711 KHz clock? That speed may be more fault tolerant and/or cheaper to implement?
Or a different approach? It just seems like shift registers would be the simplest layout for such a small space (1:1 output with the LEDs, no matrix wiring).
-TIA
