An optical turnstile is a physical security device designed to restrict or control access to a building or secure area. Optical turnstiles are usually a part of an access control system, which also consists of software, card readers, and controllers. Optical turnstiles operate much like regular mechanical turnstiles, except that they rely primarily on electronic (infrared) beams, and audible/visual interfaces to control entry. Rather than physically restraining a person, the optical turnstile uses sounds and lights to alert others to attempted entry by unauthorized individuals. For this reason, the products are not likely to be used in subways and stadiums, so much as they are suited for settings where design and aesthetics are important, such as lobbies. They are perfect for high rise buildings with a single path through the lobby and staffed reception. The rate of people passing through the optical turnstile checkpoint is high, lessening the delay that other methods would have. They are also suitable for the handicapped in that they are barrier-free.
Early optical turnstiles used programmable logic controllers and banks of relays to control the access card and infrared sensor inputs and the indicating lights and audible outputs. These older designs required a large control footprint and were very complicated.
The first optical turnstiles were developed for the San Francisco market by Omega Corporate Security of Walnut Creek, California. Early installations included Charles Schwab, East Bay Municipal Utility District, and Wells Fargo.