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Automation based on brightness
(discuss.tchncs.de)
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You might be able to get a long way without the sensors. Using a weather sensor + sunrise/sunset sensors?
I think just one sensor for outside is enough, you'll probably need to experiment with the "bright" and "dark" values. Leave a decent gap in between the two bright and dark values to avoid the blinds bouncing up and down.
You can probably make the sensor yourself with a LDR (light dependant resistor) and a microcontroller (esp32 or similar)
Relying on sun positions and weather data can be a bit hit and miss for lighting automations. I originally used to limit some of my light automations to only turn on between sunset and sunrise - when it should be dark.
But often when there was heavy cloud during daylight it would be dark enough to want lights, but the available weather data I had was never accurate enough to tell heavy gloomy clouds from lighter clouds.
I added some light sensors to the mix and my automations have been a light more accident and flexible.