Can I put a camera system, using a PIR sensor, inside a glass or plastic enclosure?
No. Glass or plastic will not allow the heat radiation to pass to the sensor. There will always be a PIR lens mounted in the front of the sensor but this is a very special tyoe of plastic. The lens is a specially designed to focus the radiation onto the window of the sensor and allow the sensor to measure the radiation within a specific area. We use a Fresnel lens which is a flattened version of the curved lens you might have seen on domestic motion detecting lights. The Fresnel Lens is carefully centred over the PIR Sensor on the control board and must not be obstructed. The lens has miniature ridges facing towards the PIR sensor. If the lens is obstructed or scratched on either side it will not work correctly. Do not mount any glass, tape or plastic film over top of the PIR sensing lens. If the infrared heat cannot pass through to the lens the PIR sensor will not read any changes.
