NFC, or near field communication, is a popular wireless technology that allows you to transfer data between two devices that are in close proximity to each other. It’s often used as a faster and more secure alternative to QR codes for other short-range applications like mobile payments. Practically, there’s not much to the technology — you have electronic reader devices that allow you to read data from various NFC tags.

That said, NFC tags are surprisingly versatile and tend to be useful in situations where you might want to transfer small amounts of data effortlessly. After all, tapping a surface takes less time and effort than using Bluetooth pairing or entering Wi-Fi passwords. Many digital cameras and headphones have embedded NFC tagger these days that you can simply tap to quickly initiate a wireless connection.NFC tagger come in a variety of shapes and sizes. The simplest ones are often built in the form of a square or circular sticker. These kinds of tags have an extremely simple construction — they consist of a thin copper coil and a small storage space on a microchip.

线圈允许无线标签sly receive power from the NFC reader through a process known as electromagnetic induction. Essentially, whenever you bring a powered NFC reader near the tag, the latter gets energized and transmits any stored data within its microchip to the device. Tags may also use public-key encryption if sensitive data is involved to prevent spoofing and other malicious attacks.

Since the basic structure of an NFC tag is pretty straightforward, you could fit the requisite hardware into a whole host of form factors. Take hotel keycards or access cards in general. These are also typically just plastic cards with some copper windings and some memory on a microchip. The same principle applies to NFC-equipped credit and debit cards, which contain thin copper traces running along the card’s perimeter.

Most NFC tags follow the ISO 14443 standard for wireless, proximity-based data transmission. There are five sub-types too, conveniently labeled type 1 through 5. Type 1 tags are the least advanced, as they are only capable of storing less than one kilobyte of data. That’s only a few hundred characters of text — so such a tag has enough memory to hold a URL or Wi-Fi password, but not much else. Transfer speeds aren’t particularly great either, at around 100kbps.