LITERATURE REVIEW

JOURNAL 2

KEYCARD LOCK

A keycard lock is a lock operated by a keycard, a flat, rectangular plastic card with identical dimensions to that of a credit card or American and EU driver's license. The card stores a physical or digital pattern that the door mechanism accepts before disengaging the lock.

There are several common types of keycards in use, including the mechanical holecard, barcode, magnetic stripe, Wiegand wire embedded cards, smart card (embedded with a read/write electronic microchip), and RFID proximity cards.

Types of card readers:

Mechanical 

Mechanical keycard locks employ detainers which must be arranged in pre-selected positions by the key before the bolt will move. This was a mechanical type of lock operated by a plastic key card with a pattern of holes. There were 32 positions for possible hole locations, giving approximately 4.3 billion different keys. The key could easily be changed for each new guest by inserting a new key template in the lock that matched the new key.

Wiegand cards

Since the keycode is permanently set into the card at manufacture by the positions of magnetic wires, Wiegand cards can't be erased by magnetic fields or reprogrammed as magnetic stripe cards can. Many electronic access control locks use a Wiegand interface to connect the card swipe mechanism to the rest of the electronic entry system.

Magnetic stripe

Magnetic stripe (sometimes "strip") based keycard locks function by running the magnetic stripe over a sensor that reads the contents of the stripe. The stripe's contents are compared to those either stored locally in the lock or those of a central system. Some centralized systems operate using hardwired connections to central controllers while others use various frequencies of radio waves to communicate with the central controllers. Some have the feature of a mechanical (traditional key) bypass in case of loss of power.

Passive RFID

RFID cards contain a small chip and induction loop which the transmitter on the keycard reader can access. The main advantages with RFID cards is that they do not need to be removed from the wallet or pass holder - as the keycard reader can usually read them from a few inches away.

Credit to : Reuban, S. (2014). Desing and Implementation of A Microcontroller Based Automatic Door NAd Visitor Counter.