The Emitter VLP20 unit emits a high power infrared laser pulse. This pulse is received by a photosensitive diode fitted with an optical filter and whose signal is processed by the incorporated circuitry of the Receiver VRH. The output changes state depending on whether the modulated beam is interrupted or not. The modulation of the emission, the particular characteristics of the optical filter and the automatic correction for ambient light make the sensor insensitive to any other source.
