HomeKit Automation for blinds/shutters to block sun

[freeman1899]

I got blinds that can be controlled threw HomeKit and together with the homebridge-weather-station-extended plugin I set them to check at certain times for temperature and Weather Condition Category (Sun = 0, Clouds = 1, Rain = 2, Snow = 3) to decide if they should close or not.

Sadly though the Weather Condition Category proves to be rather inaccurate since mostly cloudy, partly cloudy days and days with a light overcast are still treated as 0 (=sunny day). So I often have the case that the blinds would close even though there is barley direct sunlight coming in.

Does anyone have an idea for a better and more accurate way to determine this?
An idea I had is using a light intensity sensor outside (either a finished product (weather station with HomeKit support) or something made out of a raspberry pi running homebridge. but I could not find either)
Or a weather service plugin that hands a finer graduated scale to HomeKit and differentiates between sun, partly cloudy, mostly cloudy, cloudy and overcast. (could not find anything better their but maybe you got some ideas)

 

[simps100]

Unfortunately i cant help with the issue but what blinds is it you have? Am looking for blinds which support homekit at the moment!

 

[freeman1899]

I got Somfy io motors.
Somfy offers the TaHoma and the Connexoon bridge (they offer different feature sets) to make them controllable threw the internet and your smartphone. Both can be made HomeKit compatible with this homebridge plugin. (runs on a raspberry pi at my place)

Somfy announced that they will bring native HomeKit support to this system. But I am not sure if that is going to be with an update for the existing bridges or with a new bridge and I also don't know when they will release it.

 

[bripab007]

With my Serena/Lutron shades, I just programmed the automation in HomeKit to lower the shades an hour after sunrise, as that's when the light starts shining really brightly in my easterly windows. I think to get any more accuracy in your particular setup, you're going to need some other sort of direct sensor that can be tied in to smart/web-based system. Maybe there are some ambient light sensors that can be tied into HomeKit or IFTTT that you could use to trigger your scenario.

 

[Chris_k]

Somfy sell a light sensor that does this for you (obviously without going through homekit)

 

[Hanson Eigilson]

hmm, maybe use https://github.com/naofireblade/homebridge-weather-plus
it does have "Condition Category (Sun = 0, Clouds = 1, Rain = 2, Snow = 3)" but instead of using that you could check if UV index is above x value then extend blinds x time after sunrise.
UV index might be a better value to check because it's averaged out over the day, a scalable value, and it's likely to be a better indicator of heat and uncomfortable sunlight.
Might want to check wind speed too.

 

[Powerbooky]

Older thread, but I'd like to add something to it.

While the sunrise and sunset times are useful, it often doesn't close or open shutters/sun shades at the right moment.
So I've added the sun-position plugin in Homebridge. It delivers the calculated angle of the sun relative to the home location: azimuth and elevation. This way you can close/open shades when the sun actually is at a position when it the sun comes in sight of specific windows. I have a set of rules that rolls out sun shades on a terrace in the morning and back half way when the sun is higher in the sky. During the afternoon the sun moves behind the house, then everything is rolled back in again.

This works great, but rain short term detection/forcast is a problem. Open Weather Maps often reports no rain, while there actually is.