Photoelectric Sensors

Photoelectric detection systems use a light-sensitive cell and a directed light source which points directly at the cell. Photoelectric security systems can be classified as motion detection systems since an object or person must move across the photoelectric connection to break the light transmission to the sensor.

The source transmits invisible light beams to the adjacent cell or sensor. Often an infrared filter covers the light source to make it non-visible to intruders. If an intruder crosses the light beam, it breaks the beam's continuous contact with the photoelectric cell and trips the alarm. Mirrors can be installed with photoelectric security systems in order to allow one light beam to be projected across a large area, thus allowing a criss-crossing of the light beam across a room. This makes it much more difficult for an intruder to crawl under, or step over the light beam.

Photoelectric may seem an old technology, however it is still in use in many home security systems.

Learn more about home security systems.