How to switch on light when lux levels fall

I have tried to set up Room Lighting to achieve my requirements I would like to achieve the following:

When I enter a room an the lux level is above a threshold I don't want to switch on the light.
If I remain in the room and the lux level falls I would like the light to come on and if it rises again for the light to go off.
I don't want the light to come on if no one has entered the room.

Would appreciate any help offered.

You might need to do it in two steps (rules). One for managing in/out of the room and one for inside. Assuming you detect the "entering/exiting" with contact sensor, you can use Room Lighting with lux level restrictions plus it would turn on/off a virtual switch/variable to indicate the room is occupied. And then while the room is occupied, have a Basic Rules rule triggered by the lux level. This Basic Rule would be restricted by the virtual switch/variable being ON (you don't want the lights to come on when the room is not occupied).

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Easy to implement using a combined motion-sensor/lux-sensor.
Except for this part...
... and if it rises again for the light to go off.
If you switch on a light the lux level will rise above the previous threshold unless the sensor is out of the influence of the light.
So potentially the light will continuously switch on and off.

Many thanks for the help, I really appreciate such an active community.

I have reverted to Motion Lighting apps to control lighting in the rooms where it is needed as the behaviour is closer to my ideal.


As mentioned above, the only way to do this is if you have a reference lux reading that is unaffected by the lights turning on and off.

This is difficult to do though, especially if you have window coverings that are sometimes open and sometimes closed.

To do it properly you really need to know outside lux, window covering status, motion, and room lux.

I have situated a lux sensor in a room that is barely used. The sensor is mounted on the sill and 'looks' out of the window.
I then have a rule that writes the lux reading into a virtual lux device. I use this virtual device for my lighting rules.
If the light is turned on in that room then I have another rule that will pause the rule that writes to the virtual device. This way the lux reading is paused while that light is switched on and will remain unchanged on the virtual device. The rule is resumed when the light is turned off.
Works well for my setup and may be something to consider.

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My reference lux is taken from an indoor Hue motion sensor in my porch, the porch is open but the sensor is protected from the weather.

I set a Dull flag, if the outside lux falls below or rises above a threshold and use this in my Motion Lighting app to enable/disable lights upon motion.

Once again thanks for the advice.