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The Fascinating STEM Behind Hotel Room Keys

By Caroline Wells


Many hotels, among other establishments, are transitioning from a manual room key to technology involving a key card. How do these new room keys work, and what is the science behind it?

There are two main methods of the use of this plastic card. The first, magnetic strip cards (also known as “swipe cards”) involve the use of a magnetic strip containing information about the guest and a user access card, which is passed through a reader on the room’s door for verification before the door can be unlocked.

RFID cards are less cost-effective, but they tend to be more durable and long-lasting. RFID stands for Radio Frequency Identification, and the cards with this technology are usually contactless with the door or any type of reader. Instead, radio frequencies are used to determine whether to grant access to the keyholder at a certain programmed distance. In short, if the radio frequency on the door (reader) matches that of the card (carrying the tag), the lock opens. Within the tag is a circuit and antenna, used to relay information to the reader, which then converts the radio waves to a more usable and efficient form of data, usually available to be read on a computer by an employee to track where and when guests are using their keys. The ability to track the cards from a computer is also important in situations in which keys are lost and can thus be deactivated, giving guests peace of mind. Tags can either be passive, powered by the reader and thus devoid of a battery, or active, powered by a battery.

Additionally, current technology has led to the recent establishment, on both magnetic key cards and those using radio frequency waves, of a unique antimicrobial layer inhibiting the growth and transmission of up to 99.99 percent of germ, virus, and other pathogens, all of which tend to especially thrive on the surfaces of frequently-exchanged items, such as cash money and hotel key cards.

Although both the magnetic and touchless room key technology have been around for decades, the hospitality industry is constantly expanding, and the science behind simple items in everyday life is truly fascinating.


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