Turnstile Machine using Finite State Automata

Introduction :

A turnstile Machine that allows a location to have control over entry and exit .It is used to control access to subways and amusement park rides, it is a gate with three rotating arms at waist height,one across the entryway. Initially the arms are locked preventing customers to passing through. Depositing a coin in a slot on the turnstile unlock the arms, allowing them to rotate by one-third of a complete turn, allowing a single customer to push through. After the customer passes through, the arms are locked again until another coin is inserted.

HISTORY:

Turnstiles were originally used, like other forms of stile, to allow human beings to pass while keeping sheep or other livestock penned in. The use of turnstiles in most modern applications has been credited to Clarence Saunders, who used them in his first Piggly Wiggly store.

CONSTRUCTION OF TURNSTILE USING FINITE AUTOMATA:

1. The Turnstile has two States: locked and unlocked.

2. There are two inputs that affect its state: putting a coin in the slot and pushing the arm (push).

3. In the locked State, pushing on the arm has no effect; no matter how many times the input push is given it says in locked State.

4. Putting a coin in,that is giving the machine a coin input, shifts the state from locked to unlocked.

5. In the unlocked state, putting additional coin in has no effect that is ,giving additional coin inputs does not change the state.

6. However,a customer pushing through the arms, giving a push input, shifts the state back to locked.

APPLICATION:

Turnstiles are used at a wide variety of settings, including stadiums, amusement parks, mass transit stations, office lobbies etc.They are often designed to operate only after a payment has been made, usually by inserting a coin or token in a slot; or by swiping, tapping, or inserting a paper ticket or electronically-encoded card.Turnstiles are often used for counting the numbers of people passing through a gate, even when payment is not involved. In the public transport systems of the Soviet Union, the only common use of turnstiles was at the entrance to subway stations (first introduced in Moscow Metro on 7 November 1958).In the early 2000s, Moscow authorities sought to further improve fare collection; since enclosing all bus.

TYPES:

1.waist high - Waist-high turnstiles are often used in fairs, attractions, and arenas. The user inserts a ticket or pass into the slot, from which a barcode is read; if access is to be granted, a sensor determines the speed with which the user passes through, and sets the electric motor to turn the turnstile at the corresponding speed. 

2. Wall Mount tripod - The wall mount tripod turnstiles are suitable for places where installation on ground becomes impossible. The turnstile is directly fixed to the wall and all functions are achieved. Such turnstiles are usually used in narrow lanes and where installation wall is very easy.

3.optical- Optical turnstiles are an alternative to the traditional "arm"-style turnstile and are increasingly used in locations where a physical barrier is deemed unnecessary or unaesthetic. Optical turnstiles generally use an infrared beam to count patrons and recognise  anyone attempting to enter a site without a valid entry pass.

4.Drop Arm optical- The drop arm optical turnstile is a combination of the security of a tripod or barrier turnstile and a fully optical turnstile. The lanes can have either single or double arms. When access is granted the arms drop into recesses in the cabinet. Once the arms drop out of the way, the turnstile functions as a fully optical turnstile.

5. Full Height - The full-height turnstile is a larger version of the waist-high turnstile, commonly 7-foot (2.1 m) high, similar in operation to a revolving door. The full-height turnstile eliminates the possibility (inherent in the waist-high style) of someone jumping over the turnstile because of its extended height.

ADVANTAGES:

1. Better security- 

Turnstiles provide better access control by both detecting and deterring unauthorised entries. According to leading turnstile gate manufacturers in UAE, “Unlike doors turnstiles can limit the number of people who can enter or exit on each presented credential and control the direction of passage.”

2. Access Control Integration -

Turnstiles feasibly integrate with a building’s access control system.

The access control system enables turnstiles to work in accordance with doors, cameras and other security equipment to ensure only specific cleared individuals are using the entry.

4. Installation -

The layout, size, number of users and traffic patterns of the installation area determine the number of turnstiles necessary. In smaller areas, one or two turnstiles may suffice; however, high-traffic areas may require a larger number of turnstiles to accommodate the needs of the facility.