Fibaro Motion Sensors are missing an essential part

[dawiinci 5]

Did Fibaro forget to add a diffusor for the lux meter?

The readings are not usable. If the sun is shining on the square centimeter where the sensor is pointing at I get 1000 lux otherwise 30 lux.

What's the point then having such a sensor if it doesn't measure "the room"?

How are we suppose to use these?

The Aeotec sensor does it much better.

[chatting 1]

My problem is the Fibaro light sensor never showed the correct light level

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[dawiinci 5]

That's why.

It is too sensitive to bright spots in sight. A good light sensor has a diffusor to avoid this behavior.

[Vallefor 6]

Yeah... I bought one for tests recently and realised that light sensor works very strange. Now I understand why.

It still usable but I thought it should be better

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[Dalle1985 16]

This has been mentioned before. It has something to do with the design of the Fibaro MS I think. Without having pulled one apart, I would think that the light sensor (which is basically just a photodiode) is positioned in the "pupil" of the sensor to avoid being influenced by the light in the cats eye. This means that the light sensor does not get the same light diffusion as it would if it had been positioned closer to the PIR sensor.

This is just a guess however, as I've never pulled a Fibaro Motion sensor apart - but it makes sense to do it this way to avoid light polution, but it does give the problem of very localized light measurements. It is quite evident however why the Aeon is more correct if you pull one of those apart as the photodiode is positioned just next to the PIR sensor itself.

I'm affraid that this is one of those cases where form dictates function. I don't like all the flashing lights anyway, so I'd much rather have a working Lux sensor instead of a disco orb - which is also why I've stuck with the Aeon units.