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Comment by paweladamczuk | Hacker News Reader

I wonder how the camera was calibrated in terms of white balance (if at all).

I have this idea to implement in my house: a sensor that would measure temperature of the light outside and set the lights inside to the same temperature. Getting this measurement right seems to be non-trivial. Though maybe it wouldn't have to be exact in terms of physical units, a pair of sensors calibrated together (one for outside, one for inside) might achieve the desired result too.

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I think it must have a fixed white balance, or the average hue captured would hardly change over time at all.

Adjusting the inside lights until the inside sensor is satisfied, rather than based on specifying in absolute units, would also have the benefit of taking into account any influence on indoor overall color contributed by your walls, window coverings, and anything else. Might need to average multiple sensors for best results, unless a single sensor does that through a wide angle diffuser.

This is a bit like how automatic audio equalizers (I think Sonos offers this, for example) don't work just by ensuring that the speaker delivers the desired frequency response curve (or lack thereof), but by actually using a measurement mic, since your experience will be influenced by the combination of speaker+room. The difference is that you only need to have the mic around when making changes to the room/furniture (which is rare) whereas you'd be making changes to the indoor light bulbs continuously (based on outdoor light), so you need your indoor sensor running continuously.

Your idea is pretty straightforward. Set up a camera outside, point it at the sky, capture a screenshot, average the color, set smart lights to that color.

Presto, yellow sky makes yellow light.

You’ll quickly grow tired of how it looks. And not because it isn’t calibrated correctly.

What the high end variable-temperature lighting systems seem to do is just use your clock and latitude to simulate what color temperature the sky would be at a given time of day, and set the lights to that.

I've never seen it in action, I only have boring old single-color lights. I am not really annoyed by 2700K lamps during the day, and mixing daylight and 2700K doesn't really look as awful as you'd think during zoom calls.

The main point is that those high end systems won’t look any better to you just because they calculate out a color curve based on your lat,long. It’d look just as good if you point a camera at the sky. Your high end systems also won’t capture changes in weather, so that’s less cool. But then you’d get bored of it looking rainy whenever it rains.

Could be mistaken but I think my Mac already does this -- it has "true tone" and when I open the lid, my main external monitor changes color temperature.

I wonder if there's a way to scrape that data and then send it to Home Assistant for light control.

If only color calibration were that easy.

People should really get comfortable with the idea that color is relative, so choose whatever looks nice to you and stick with it. True Tone certainly isn’t scientific.

In this scenario, all that matters is that the instrument doesn’t try to change its white balance. You can actually calculate the spectral energy of the sky based on these color changes alone, and it doesn’t matter if you start at a white balance of fluorescent or incandescent.

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