But there is really almost nothing to report of. Except that I have modified a couple of cameras so they are sensitive to infrared and verified that the red-eye effect is observable in infrared. It's still unclear, what wavelength I'm using, but I've ordered a bunch of IR leds for which the wavelength is specified. And a bunch of photodiodes and an amplifier.

I also plan to do some experiments with an image sensor instead of two photodiodes, to get some extra info.