|Motion sensing night light|
|Motion sensing night light only activates in the dark|
The sensor is a Passive Infrared Sensor (PIR) that works by detecting infrared light emitted by warm bodies. The lens in the dome of these sensors focuses IR light onto a device that triggers when it sees warm objects passing across its field-of-view. There is also a photocell that detects ambient light level and disables the light when the ambient light is above a certain threshold.
I am so pleased with these lights that I plan to order a couple more. While they do use more energy than other types, I have enough surplus power from my solar array that I can spare a few Watts. I have not paid for grid power since May (just payed my Sept-Oct bill and still have a credit on my account thanks to net metering).