GEX experiment: RGB ambient lights

Here’s a thing I wanted to do for a long time and the idea that actually made me think of creating GEX. The firmware is still in super-early alpha, not even published yet, but I got Pin and Neopixel units working and put together some hacky screengrabber script, so here we go!!

I wanted to have nice ambient lighting for watching movies that e.g. turns dark in dark scenes, blue underwater etc. This has been done a million times before, so, uh, i++.

You can see (most of) the source code here: source gist

This script was put together while watching Wonder Woman, which btw is pretty good!, and you could probably tell from how messy the code is. I also fixed some issues in GEX where it would put random glitches on the Neopixel strip due to interrupts firing despite it being inside a critical section ?? (or maybe it was something else)—anyways the bug is gone.

I’ll make a repo for this project later when I have more time to also improve the algorithm. At the moment it grabs some colors from the X11 screen buffer (which was a great fun to figure out), sends them through a simple averaging filter and dumps them to TinyFrame.

Here’s the grabber code being tested separately in Xterm

I’m using the “NEOPIXEL” GEX unit instance sitting at callsign 2 and load it with command 0x02 which is “Set all pixels, no packing, little-endian”. Of course the “NEOPIXEL” unit (or the protocol itself, for that matter) has no documentation yet because it’s all very experimental and prone to change as I add more units and fix any potential friction.

Demo

here’s the whole thing in action:

What’s next

There’s still a lot of room for improvement, for instance:

• Use some color averaging / interpolation instead of point samples
• Add support for multiple strips (top, bottom, left, right)
• Clean up the horrible code
• There’ll be a proper tidy GEX API available later, so use that instead of hacking the protocol by hand.
• Make a repo for this thing