Tap to Convenience
In a world where convenience is king, the evolution of payment methods has been nothing short of revolutionary. From bartering goods to digital transactions, the way we exchange value has transformed dramatically. In India, UPI is the most convenient payment method. But in most of the western world, tap to pay is the preferred way to pay.
Have you ever noticed a symbol on your credit or debit cards that resembles a Wi-Fi logo? This symbol signifies that your card is equipped with tap-to-pay functionality, offering a swift and secure method of payment without the need for entering a PIN code. However, the technology behind this symbol is not Wi-Fi, but Radio Frequency Identification (RFID).
Radio waves, a type of electromagnetic radiation, are used for everything from broadcasting our favourite music to connecting our phones to cell networks. Radio Frequency Identification (RFID) technology harnesses the power of radio waves to wirelessly identify and track objects.
The primitive versions of RFIDs could be traced back to 1945 in Soviet Union. The same technology was used extensively in World War II to identify friendly and enemy aircrafts. One of the first patented RFID devices was used for toll collection.
Today, RFID is utilized in various consumer applications such as FASTag, ID cards, Metro travel cards, Bus Cards (like Chalo), and building access cards.
Let us look at how this ubiquitous piece of technology that has brought us convenience works.
An RFID system comprises two key components: an RFID card and a reader. The card stores a small amount of data. When the card comes within range of the reader, the data is transmitted wirelessly. This functionality is like barcodes, but with a crucial difference: barcodes require a direct line of sight between the code and the scanner. RFID cards, on the other hand, can be read even when not in the reader's direct line of sight, if they are within the appropriate range. This range depends on the frequency of the radio waves used.
There are three main categories of RFID cards based on their operating frequency:
Low Frequency (LF) (125 kHz or 134 kHz) - Short range (around 10 cm)
High Frequency (HF) (13.56 MHz) - Medium range (around 1 meter)
Ultra-High Frequency (UHF) (860-960 MHz) - Long range (10-15 meters)
You might be wondering, but what about those RFID blocking wallets? How do they work?
RFID blocking wallets protect your personal information by using metals to block radio waves. They work like a Faraday cage, creating a barrier that prevents RFID readers from accessing the data on your cards. This ensures your sensitive information on contactless cards is secure from unauthorized scans and potential theft.
It should be noted that these only work for low frequency RFID cards but since almost all RFID cards used for commercial purposes come under this category, the RFID blocking wallets are effective.
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An RFID card might seem like a technological marvel, especially considering its lack of a visible battery. It need not always be the case. RFID cards fall into two categories based on their power source: Active cards and Passive cards.
Active cards contain a battery, allowing for longer read ranges and the ability to transmit data over greater distances. Active cards usually contain an antenna, chip and transponder along with the battery.
Passive cards on the other hand, commonly used in tap-to-pay applications, are minuscule with only an antenna and a chip, lacking a battery.
So, how do they power themselves? The answer lies in the reader's radio waves. Passive tags utilize a rectifier circuit (embedded in the chip’s housing) to capture energy from the RFID reader's radio waves and store it in a capacitor. This captured energy then powers the RFID tag.
Since passive tags don’t have any battery attached to them, they can be made tiny and compact enough to fit in a credit card or even the FASTag sticker!
RFID technology may seem like something out of a sci-fi movie, with cards seemingly working without a battery. But the science behind it is quite clever. From enabling speedy transactions, hassle free toll payments, to providing secure access control, RFID is woven into the fabric of our daily lives. So next time you tap your card or zip through the toll gate, remember the power of radio waves and the invisible technology that keeps things moving.