A colorbox
When I photograph small things, I'd like a variable color light. This is a gadget box to do that - it has 3 knobs on top, for red green and blue, and it generates a monitor output with a screen full of that color. In effect I'm going to use an HDMI monitor as a colored area light.
It starts with an Adafruit Metro M4, running Circuitpython.

On top of that, the Gameduino Dazzler for HDMI output:

For the input interface, I used parts from Electric Dollar Store:

$8.40 and ten minutes later, I had a 3-potentiometer I2C peripheral, which plugs in on top:

With the knobs on, looking quite functional.

The CuircuitPython code is short and sweet. It reads the R,G,B values from the three I2C knobs, and clears the screen. I added small dials at the top so I can keep track of what colors work.

All in all, quite satisfying. There's a feeling of the instantaneous feedback when you turn the knobs to fine-tune the screen color.
Thanks for reading.