PL-N823-01 - 

KEMET's PL Sensor use the passive pyroelectric effect of ceramic by reacting with infrared rays emitted from the human body. Because it does not radiate the PL sensor detects human presence without lens. KEMET's proprietary piezoelectric material makes it also possible to detect humans through glass or resin and these materials can be semi-transparent. The PL sensor is low profile, does not protrude and does not require any aperture. This gives you more freedom in the design of the visual appearance of your product.