Lux sensor inside or out?


(Calvin Robertson) #1

I’m looking to get a fibaro sensor to use the brightness measurement to control my lights during the day. The question is do I place the sensor outside and measure outside light or do I place them inside? My only concern is the tuning of the control if the sensor is inside. I worry that it’ll be dark, the control will turn on the lights, but then turn them back off because now the lights have made it brighter.


(Gary D) #2

I’ll try to answer with a real world scenario:

I have a fibaro motion sensor in my home office. At night, with the lights on, it measures a mere 9 or 10 lux. In the daytime, with the window shades open, it measures over 100 lux consistently - up to over 500 lux (depending on the location of the sun.)

The point I’m trying to make is that most home lighting can’t even compare to the brightness of light coming from the sun…


(Ron S) #3

My outside Fibaro goes up from 0 to 9000 plus lux based on darkness to sunlight (at different times). Check the thread "interpreting lux values). Finally I went with my living room Fibaro inside with 30 lux to turn on lights when we get back home…between 4:00-5:00 pm.

Currently it is sunny outside with lots of snow outside and no direct sunlight in the room but bright inside…

UPDATE: in fact there is some direct sunlight coming into the room with shades up.


(Gary D) #4

@smart, what are you using to turn on the light based on motion AND brightness?


(Eric) #5

If all you want is outside lux then you can install a virtual weather station for use by SmartThings, including lux, temp, humidity, etc. You don’t have to get a physical sensor so you can experiment now. IMO you need an indoor lux reading in any case.

example= SmartWeather Station Tile
and Convenience app/SmartWeather Controller.
Don’t be confused - it doesn’t actually control the weather. It refreshes the temperature from the weather station.

log:
Outside-v1 illuminance states
Date Name Value Units
2015-02-17 1:41 PM EST - 40 minutes ago illuminance 10000
2015-02-17 8:41 AM EST - 6 hours ago illuminance 7500
2015-02-17 7:41 AM EST - 7 hours ago illuminance 753
2015-02-16 6:37 PM EST - 20 hours ago illuminance 10
2015-02-16 5:37 PM EST - 21 hours ago illuminance 128
2015-02-16 2:37 PM EST - 24 hours ago illuminance 1000
2015-02-16 12:37 PM EST - 1 day ago illuminance 2500
2015-02-16 8:37 AM EST - 1 day ago illuminance 7500
2015-02-16 7:37 AM EST - 1 day ago illuminance 4904
2015-02-15 6:37 PM EST - 2 days ago illuminance 10


(Mike Maxwell) #6

I have my fibarro outside under an eve, behind a translucent (not clear) piece of Lexan to act as a diffuser and protect it from rain.
I didn’t want interior lighting to interfere with the lux readings, particularly at night.

I have three apps I use specifically for controlling lighting:
–Smart NightLight (has motion and lux sensor inputs) for lights that I do not want to come on unless it’s truly dark outside.
–Light on motion for those that I want to come on all the time
–autoDimmer (my app), that captures a dimmers on() event and then resets the current dim level based on 4 lux ranges.

Smart nightlight and light on motion both have mode selections, so most if not all the automatic lighting is only set to fire when there’s folks in the house.

With the auto dimmer app monitoring and adjusting the dimmers states dynamically, I have no need to have modes specific to lighting states, or base lighting on time of day. My modes simply reflect the state of the homes occupants.


(Dave N) #7

I don;t use the virtual LUX settings as they don’t accurately reflect the clouds that come and go hourly (especially in the winter). I have an AEON multi at the top of my window behind the blinds. When turning the light on in the room the LUX still went up significantly so I built a little shade around it to stop the room light from reaching the sides.


(Ron S) #8

For the lights I have some custom code which turns on the lights when one of us get back and it’s dark inside. PresenceHandler…someone is back…illiminance sensor… Lux cutoff… @Mike_Maxwell posted a code few days back…