How does an optical turnstile work?
Most large amusement parks, stadiums, subway systems use physical turnstiles to make sure that only one person enters for each token, payment or authorization presented. A metal bar is locked into a blocking position to prevent someone from walking through the passageway. When authorization is granted the bar is released and one person can walk through. The bar is re-locked after a person walks through the passageway. An optical turnstile uses a card access system to determine when authorization is granted, and infrared sensors to detect a person walking through the passageway. No physical barrier is present. If a person walks through the passageway without authorization, then an alarm is generated. A sounder is activated, the card access system is sent an alarm signal, and a guard should respond to the alarm.
