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| author | jaseg <git@jaseg.net> | 2019-04-17 16:32:43 +0900 |
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| committer | jaseg <git@jaseg.net> | 2019-04-17 16:32:43 +0900 |
| commit | 9eef62547efdf8e18009b6d6d6b3f7c80bf64e13 (patch) | |
| tree | 8594db8c91ddc47614859e4eabbc9e7cf36d0d09 /center_fw/notes | |
| parent | f6b959086671fb1bf8b2003d5c5384c7311a7735 (diff) | |
| download | 8seg-9eef62547efdf8e18009b6d6d6b3f7c80bf64e13.tar.gz 8seg-9eef62547efdf8e18009b6d6d6b3f7c80bf64e13.tar.bz2 8seg-9eef62547efdf8e18009b6d6d6b3f7c80bf64e13.zip | |
center/fw: Add backchannel infrastructure
Untested!
Diffstat (limited to 'center_fw/notes')
| -rw-r--r-- | center_fw/notes | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/center_fw/notes b/center_fw/notes new file mode 100644 index 0000000..99a8b2a --- /dev/null +++ b/center_fw/notes @@ -0,0 +1,10 @@ +Pink led strip details: +at Vcc = 11.88V, the voltage across the 68R dropper resistor is 2.06V. +Thus, I is 30mA, the forward voltage of the LEDs is 9.82V/3 = 3.27V. +A single group of 3 LEDs dissipates 0.36W. At 60LEDs/m that's 7.2W/m. + +We loose 50% brightness due to the 2:1 AC multiplexing and another ~15% due to the generous blanking periods. To make up +for that we need to scale the current by a factor of 2.35. This can be done by increasing VCC from 12.0V to about 14.5V. +Assuming the multiplexing doesn't stop that's not a problem as the power dissipation of the LEDs and dropper resistors +will remain the same as before. We need a safety cutoff in the circle firmware for that though so the LED tape doesn't +burn up if something crashes (FIXME). |