Adjust dimmer switch (up/down/off) based on lux level

Questions & Help
1

Looking for creative ideas (or solutions you’ve implemented) on adjusting light switch dimmer levels up/down/off based on ambient light level in the room. Two high-level use cases:

  • Lights are turned on in the morning when it is dark outside, and dim-to-off as the sun comes up
  • Lights turn on in the evening as the sun sets and the room begins to darken

It will take some trial and error to map lux levels to switch dimmer % changes, but I was hoping to hear what you’ve done and use that as a starting point. Thanks!

2

You may want to have a look at the app Circadian Lighting in combination with a Light sensor, alternatively the app Sun Events.

Regards
Niclas

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3

This is a really nice idea and I recently implemented it for my living room as well. It’s not perfect yet, but here is what I did:

I installed an Aqara motion sensor that also provides lux information in the living room. Although a motion sensor isn’t the best option for a living room (a presence sensor might be better), it works great for me now for a couple of months.

I have created an advanced flow that checks for the amount of light in the room. When it becomes under a certain level (in my case 50 lux), the lights turn on automatically when at least one of the following requirements is met:

  • the room is active (meaning, the sensor recognized movement),
  • the tv is turned on,
  • the radio is playing.

Of course, this list of requirements will be different for everyone. But in my case it works really well.

Since I’m using a motion sensor that might not always see movement, I extended the timeout to 15 minutes.

If the requirements aren’t met, the lights do not turn on. But when someone enters the room later, the lights still turn on as the motion sensor will turn the room active.

Addtionally, I have a created a second flow that turns off the lights when the light becomes above a certain lux-value (in my case 60). It is 10 lux higher than the “turn on-requirement” to prevent lights switching on and off too often. That happened to me when there was dark weather in the evening, that reduced the amount of light quite much.

One thing that caused a little headache was that sometimes the lights turned on quite late. The reason for that is that the Aqara sensors do not continuesly provide lux information. To solve that, I have included the lux information of other Aqara sensors in my house as well, which make the actual information more reliable. For those sensors I had to use different lux values, as the amount of light in the corresponding rooms is different.

Since I’m using multiple scenes (flows) in the living room, I have created a variable that stores if the lights were turned on automatically. Only if that’s the case, the lights can be turned off automatically. When someone turns on the lights of changes the scene, the “automatic behaviour” is overwritten and the lights will no longer turn off by itself. But that of course is personal preference.

I hope this gives you some nice ideas for your own implementation. Good luck with it!

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