From Zoom calls to SciFi effects films -- you can do it all with a DIY chromakey background made from retroreflective fabric, lit with a lens-mounted NeoPixel light ring. A QT Py microcontroller running CircuitPython allows you to control the light ring color and brightness with a push and twist of a rotary encoder knob.
Create chromakey mattes to place your subject in front of any background image or video you like using a retroreflective greenscreen/bluescreen -- you decide the color you need with the press of a knob.
Traditional greenscreen/bluescreen backgrounds are tricky to light evenly, and require a lot of space to prevent your subject from casting shadows and receiving green/blue spill. This retroreflective screen solves all of these problems -- and costs less, too!
This rig works equally well with realtime keyers (built into Zoom, OBS, and others) as well as offline compositing software, such as DaVinci Resolve or iMovie.
A friend of mine told me about this technique and said he'd built a DIY version that worked great. I figured NeoPixels would work well for this and my buddy gave me some spare retroreflective screen material to test it out. I did a quick test and found out that it works better than I'd hoped!
You'll also need a single #33 size (approx. 3-1/2" x 1/8") rubber or silicone band. I like the silicone hair bands like these.