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I bought a motion detector light a few weeks ago. It worked great out of the box, but now its sensitivity has lowered a lot. You need to be really close to it for it to detect motion.

I tried cleaning dust, but it was not dirty.

Is there way to make it more sensitive? If I remove that white plastic that covers the light sensor, will the sensitivity improve?

I know it might make inside electronics dirty, but I don't care about that I can just clean sensor every week.

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What kind of motion sensor is this, an outdoor security light, or one for a light switch? Is there an adjustment for sensitivity? What's the ambient temperature, has that changed in the past few weeks, and is the sun hitting the sensor directly? – BMitch Sep 29 '13 at 11:07
    
Do you have the instruction manual for this light? Typically these lights have some sensitivity adjustment available on them. If not, return it and buy one that does. – Tom Swifty Sep 30 '13 at 17:17

Removing the white plastic that covers the light sensor will make the PIR/motion sensor less sensitive/effective. The cover is actually a Fresnel lens, it has a pattern that scatters light in different directions, increasing sensitivity dramatically (e.g. when light passes through a part of the cover that is 0.5mm away from where it was before, it is sent into a different direction, making it appear as if it has moved more than it has).

I would suggest cleaning or replacing the cover (especially if it is old and has become damaged/dull/dirty). Some PIR sensors also have a dial to turn up or down sensitivity.

I know this is an old question, but it may help others.

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