Have you considered manufacturing f.lux for home lighting, such as a wall-mounted controller for Hue or Ikea bulbs that changes color spectrum depending on time of day? Or possibly bulbs with f.lux build in, so no external controller is required?
Yes, we were looking at this quite a while ago. Lighting is a really hard business (especially residential) so we did not make the leap, and mainly have tried so far to work with people who are in that business.
We thought back then that some form of "smart lighting" would be universal. This mostly hasn't happened, so the truth is that the opportunity is different than we had guessed. Today most "smart" replacement lamps are $20+, similar to several years ago, even though normal lamps are $1.
We do support a lot of integrations with f.lux on Windows, so people can use f.lux with their Hue/LIFX/yeelight/etc., but it is somewhere <2% of our users right now.
Out of curiosity, what makes lighting such a hard business?
I have given the issue some thought as well. f.lux integration with Hue is great, but unfortunately not a solution for me, as I'd have to keep my windows pc running all day.
There are apps, such as iConnectHue, which are able to install a preset on the Hue Bridge that dims the lights or changes the color temperature without needing any computer or phone turned on when the timer fires.
The fact that bulbs are 1. small and 2. run on mains electricity is a big complicating factor. By far the easiest way to build this would be with dual-colour LED strips. But that's not how most people want to light their homes.
I think it's the cost. You can make a cheap driver off 120V that looks like shit and has terrible thermals.
A solid driver with good filtering and good thermal characteristics is expensive. So you're left with a $15 LED bulb that sits on a shelf next to $5 bulbs, selling to customers who see nothing other than two LED bulbs where one is grossly overpriced for no reason they can comprehend
As a software developer, the fact that I even have to build custom electrical hardware is a significant barrier.
The fact that this hardware runs at 120v (or 240v in my case) makes it the barrier higher as there's now a chance that making mistakes might kill me.
Additionally, the high power levels mean that adequate cooling is needed, and as a non-expert it's hard for me to know whether I've done that correctly.
While possible (there are tons of "blue filters" on the play store), the effect will always be considerably worse that with root access, since apps can only display overlays, not change the screen's white balance.
Btw, if you don't insist on using f.lux and have root access, take a look at cf.lumen: It allows much more precise configuration (I have it remove almost all blue in sleep mode).
I have some Osram Lightify bulbs along with Home Assistant to do this.
During the day time all my bulbs are at 6000K and 100% brightness, at 6pm the bulbs in my bedroom/office dip to around 4500K and 50% brightness, and at 8pm to 2700K and minimum brightness (we have a toddler).
In my kitchen/living room during the day it's the same, at 8pm to 4500K at 50% brightness and at 11:30pm to 4500K at minimum brightness.
I considered having the schedule run on when the sun sets, but in my location that is 10pm in the summer and 4pm in the winter so it doesn't really work at the extremes (I have the same complaint with tooks like f.lux as well :D).
I've been looking for a hardware solution to this problem so long.
I would kill to have like a programmable dimmer knob that can progressively adjust both temperature and power set to a fixed temperature and power at start (ie: 3750k at 100%) and finish (ie: 2500k at 10%) positions then it auto-calculates the right spot in-between.
I did it with a Pi, HomeAssistant, smart bulbs, and some Python, but it was not as good or as reliable as I'd like.
I wanted the lights to know what temperature and brightness to turn on to based on a schedule, but there wasn't a way for them to pull the desired state upon power-on; instead I'd have to detect power on and push a state change to the desired color temp. This meant they'd turn on at whatever last state they had on power-off, and a few seconds later (or frequently much slower) adjust to scheduled color temp.
This may have worked better had I used smart switches to turn lights on/off rather than wall switches that cut power to the bulbs, but I also had issues with the smart hub losing connection to bulbs occasionally, HA not reliably seeing power-on events for the bulbs, and HA losing connection to the hub. (Bulbs/hub were Ikea tradfri; perhaps other manufacturers' products are more reliable).
This was a couple years ago; I haven't looked into it much since - maybe it would be easier to do now.
Phillips makes a bulb that does this with those temperatures almost on the mark. I put them in every fixture in my home and got lutron casetta smart dimmable switches. Drops to 50% at sunset and 20% at bedtime.
