Let's talk creative uses for Lux (Luminence) sensors

Hey everybody let's have a fun discussion about creative ways to integrate Lux / Luminence sensors into the mix.

My mind will be thinking of the Phillips Hue Outdoor Motion Sensor for my thoughts, but any Lux sensor should work as well.

  1. Mailbox notifications can be achieved by measuring the lux levels when the mailbox door is opened. May not work in the winter if you have very late mail deliveries. The Hue Sensor could fall back on it's motion detection, which is not affected by heat.

  2. Fridge notifications - A lux sensor could sense when the door is left open by either seeing the light through the crack in the door, or just when the fridge bulb turns on. Bonus here for the Hue, it could also measure the temp to let you know when your fridge is too warm...this combo can tell you why (fridge broken, or door left open)

  3. Very iffy would be mounting a Lux sensor very close to a device that has LED warning lights or such. Not exactly sure if they would trigger lux, but I would think so. Could be for dishwasher done, Microwave done, smoke alarm batteries need changing. Who knows, this one is definately more of an experiment.

That's just a few that comes to mind. Obviously some of these could be accomplished with other sensors, but sometimes that just doesn't work. So be creative. What could you use Lux sensors for?


I've got #2 already set up in my fridge, and did try #3 without luck, on a dehumidifier to detect the red "tank full" light

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I seem to remember a device (zigbee?) where you can put it over an led and it will see when that led is on or off....


For some of the examples in #3 you could use an energy monitoring smart plug... But that's not the focus of this topic....

You could probably use a contact sensor for #2.... And I would expect issues with transmission in a fridge.

For #3 you could build a sensor easily enough and use hubduino to bring it in. Lots of Arduino led detection examples out there.

Silly me... I just have one near my skylight. I set two global variables based on illuminance: darkInside and darkOutside. A lot (all?) of my lighting rules depend on those variables.

I thought about putting one inside my garage door opener light housing so my shop lights turn on when the opener light turns on.

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I would like to try and use some hue outdoor motion sensor lux readings to manage the opening and closing of my blinds each day (I face East / West)

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Yes I remember that but can't find it now.

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Could this be it?

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Could be, I'd formed a memory of it being less bulky than that but that's probably the one.

I currently use Centralite contact/temp sensors in my fridge and freezers, the fridge and freezer doesn't seem to affect the battery or signal.

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That's it. I couldn't remember who made. it.

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I likewise face east/west, west being the side the shades are on. I use time after sunrise to lower the shades 50% when the sun should be directly overhead and 100% when the sun is a direct hit. I'm using the rule for solar heat blockage but something similar might work for luminance level excluding a shady day which is not common where I live. I also use the weather flow Tempest wind speed/direction attributes to open/close the shades based on wind.


I use lux in my living room to close the shades when the sun starts to shine in that particular window. Works better than I expected. Shade stays open if its cloudy. Our master bedroom is set up similar, but I use an outdoor motion/lux for the lux threshold.

This keeps radiant sunlight from heating the rooms up in summer to try and save a little on the AC bill. I also have an outdoor temperature threshold to keep the shade open when its cold outside to gain a bit of heat in the rooms during winter.


I use the lux sensor on my weather station to decide the opening and closing of my blinds. I have different open/close values for different sets of blinds. I even created hub variables so I can make changes to the lux levels that trigger the opening/closing from a dashboard, so I don’t have to edit the rules. What I have yet to do is set up interior lux sensors to close the blinds when the sun glares in.

Here’s a different idea. Use one in the children’s rooms to let you know if they have turned their light on to play after bedtime.


Liker @wayne.pirtle , after I install my Tempest weather station I'll use it to control my iblinds motors at the front and back of the house...

We do that with a rule. It notifies us if my 4 year old turns on the light and then automatically turns it off. (rule fires after 8 but we put him down at 7:30) He used to do it all the time, once he realized it was useless he stopped turning on the lights :joy:


I have illuminance sensors in multiple rooms that will stop lights from automatically turning on when it is already bright enough in there…

I have another close to a light and if it doesn’t turn off as it should, another rule will try to turn it off based on illuminance.


like @Sebastien much of my lux control deals with controlling lights abilities to go on if lux in the room is past a certain point. The problem I have with Lux is the relativeness of it - somedays it feels like a light should go on but doesn't due to lux, other days lights go on and it feels like it's unnecessary. In general, I use the Lux value I get from OpenWeatherMap to give me outdoor lux as a general measure and thats worked very well for a long time.

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Back in the day when you could still go to Radio Shack, I went there and just bought a small pack of basic photoresistors. One in the pack would pick up the LED from our laundry machine and change resistance enough to trigger a simple contact sensor (an Insteon IOLinc for me at the time)...some white tape (to match the body of the machine) over it over the LED and it would only get light from the LED...some quick coding around how the light worked during/after the cycle and we had text alerts to our phones whenever the laundry was done. :tada:


That's why I have never automated my lighting (other than the outside lights go on if there is an intruder detected at night). For everyday use my lighting rules are controlled by buttons, dashboard and voice.

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