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ebaauw / homebridge-hue

Homebridge plugin for Philips Hue
Apache License 2.0
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Dew point for temperatur sensors #1080

Closed Nastras closed 2 years ago

Nastras commented 2 years ago

Hello @ebaauw

would it be possible to have the plugin calculate a dew point value from temperature and humidity for temperature sensors like Aqara and display the dew point value in homekit on the device?

I think it would be a great function to use the values of two sensors in an automation to detect the right time for air exchange / ventilation.

King Regards Nastras

ebaauw commented 2 years ago

Happy to expose dew point for devices that report it, but Homebridge Hue won’t be calculating it. That’s a feature for a home automation system, nothing to do with exposing devices to HomeKit.

Nastras commented 2 years ago

In principle, I agree with you. Unfortunately, it is not so easy to calculate this dew point reliably in Homekit. Shortcuts would be a possibility. But it is also quite unreliable.

Therefore, my idea was that you can calculate these two values Temp and humidity possibly from homebridge-hue.

Would be a great function but I can also understand your answer 😉

Thanks and have a nice weekend!

ebaauw commented 2 years ago

Looking at https://en.wikipedia.org/wiki/Dew_point, there’s a simple approximation (+/- 1°C) when relative humidity > 50%.

Not sure I fully understand the formulas, but it looks like a more exact calculation would need to consider air pressure as well.