We use a motion sensor light in our restroom to prevent forgetting to turn of the light.

However, the light has not worked well theses day..

After thinking it a little, I noticed the reason.

The motion sensor light detect a changes in infrared radiation with moving human body, and turn on the light.

Then the tempterture of the restroom is higher than those of human-body, the sensor cannot detect any infrared radiation.

Therefore wherever and whenever the temperature is higher than 36 degrees Celsius, the effect of security lighting with infrared radiation sensors is missing perfectly.

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Tropical nights with temperatures exceeding 36 degrees Celsius at night -- just thinking about it is a nightmare.

However we must remember that nobody could predict a series of extremely hot days (more than 40 degrees Celsius) a few years ago.