RGB gamma and other compensations

[garthk]

@marcmerlin, the gamma adjustment code in #38 helped get the orange right but it strikes me:

• The blue is too dim, which I'm guessing is just these pixels not being that great
• The green is too bright, which might instead be the human retina
• The gamma might not match my pixels because I just grabbed someone else's table
• The ESP32 might be strong enough to generate its own tables at boot time off configured gamma and LED strength adjustments
• It'd be nuts to keep all that to just one plugin when it could be in aiko.led so everyone could get their colours right first try

Got any links handy I can follow to learn more? I'm happy writing the code up. :)

[marcmerlin]

honestly, I'll leave this to andy. I care about colors when I have 2D matrices, but for a strip around my neck, I really don't care :)

[garthk]

The blue is fine on the long strip with dedicated power, so I think the problem there might have been running it off 3.3V. This might then not be worth any effort unless it helps keep the colours straight despite dimming.

[marcmerlin]

oooh, right, they are being undervolted, so they probably do not give the correct color, good point. This brings us back to https://spectrum.chat/lca2021-swagbadge/hardware/on-the-mythical-5v-rail~0827bdfe-d608-4021-b04c-b0d260ffa833

We really should find a way (if possible) to get Vcc out of that chip

[garthk]

Looping back: I rigged my badge to drive a strip in my Xmas tree. Mixed colours proved so difficult to get reasonable I'm going to rig up an RGB sensor eg. this TCS34725 module knock-off I've got lying around, crunch numbers, and see if I can come up with a convenient compensation system.