Alignment system using two photocells directed at each other

摘要

A passive optical switching apparatus for use with a sales display device, or with a secret security device or with a safety device. The apparatus includes two photo resistor systems which are positioned so that their optical axes and field of view intersect. Also included is the complementary electronic circuitry. If a light change occurs within the region defining the intersection a switching signal is created to trigger the device to which it is attached.