[mwwilson]

My understanding is that different wavelengths effect sleep hormones differently. My less than educated guess would be that evolutionarily speaking there are different optimal sleep environment cycles based on wavelength, intensity, and temperature variables depending on location and habits of ancestors.

[bloopernova]

You're absolutely right, our body most definitely reacts in different ways to different wavelengths of light.

A specific green has been shown to help reduce pain. [1] 525 nm seems to be the magic wavelength in this particular case.

I'm a chronic acute pain sufferer. I'd love for something as simple as an array of green LEDs to help with my pain. I keep meaning to get a large breadboard, a bunch of LEDs, and make such a device.

I wonder what effects other wavelengths might have? Would lights help sleep if they matched sunset darkening to night time through purple and indigo? It's fascinating stuff.

https://www.ncbi.nlm.nih.gov/pubmed/28092651

[flowless]

I have an amibilight built around WS2812 LED strip and esp8266. I use it to display a colorful rotating gradient during a day and as a night light with red color.

Small Haskell program using reactive-banana-automation feeds simple nodemcu firmware every second with UDP packets. It's quite easy to build RGB light this way as only one signal wire is required.

[swsieber]

Red light helps cells heal [1], ultraviolet light can kill bacteria. I'll find sources and measurements.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4148276/

[jsty]

There was an interesting piece [1] on the BBC a couple of days ago about research finding exposure to Cyan might help keep us awake.

[1] https://www.bbc.co.uk/news/education-44565320