How can RFID cards be read from a distance?


The Delhi Metro Card is currently one of the largest Serial RFID Tag Production runs in the world!

Well, that’s because these cards don’t use the traditional Magnetic Stripe or Smart Chip to uniquely identify themselves to the card reader; In fact, they’re not cards at all! These are actually known as ‘Tags’ because they are rather miniscule, and are placed in a large plastic case simply for ease of use.

RFID stands for Radio Frequency Identification and entails that each card transmits a Unique ID code as a pattern of Radio Waves at a specific frequency, this frequency must match the receiving frequency for the code to be read and given a positive or negative response (eg. Whether to unlock the door or not)

You may think that this technology seems a bit futuristic and impractical for use in today’s world, but


We must have seen a Toll-Collection Tag like this at least ONCE in our lives!

the chances are there is at least one RFID tag present in your wallet! It can be disguised as a Hotel/Office Key, Metro Card, Frequent Shopper Card or Driving License!

Tags are rapidly replacing Chip-and-Pin, Magnetic Stripe and Barcode systems globally for an arsenal of reasons:

Reusability: RFID tags can be easily reformatted an unlimited amount of times to depict another item or key, such as in Hotels, any tag is recoded to act as a key for a specific room.

Multitasking: An RFID receiver is capable of reading and processing multiple tags at once, such as a single receiver on a Highway, collecting the Tag IDs of vehicles in multiple lanes.

Physical Versatility: Due to their small size and large range, they can be fitted to almost anything


When I said small, I meant it. Shown is one of the earlier mass-produced Tags, next to a grain of Rice. There are currently reports of tags around 55% of this size.

from a USB drive to a Shipping Container to a Sock!

Technical Versatility: Depending on which has more ready access to a Power Source, Tags and Readers can be Passive, Active or Battery-Assisted (Active needs a live Power Supply) without hindering Performance, as long as at least one of the components is Active, as this allows it to ‘Scan’ (If it is a Reader) or ‘Ping’ (If it is a Tag) for the correct counterpart.

Relative Motion: Unlike other systems, Tags do not have to be stationary with respect to the reader to be detected.

Convenience: It can be scanned through your wallet or Pocket, no more Fumbling for cards!

Cost: The most important factor in today’s Economic world. Contrary to popular belief, RFID tags and readers are typically cheaper than equivalent Smart Card equipment!

Curiosity note: Ever wonder why some Government/Military Vehicles have blank Number plates? Apart from them being easily distinguishable from Civilians, the RFID tag is embedded within, or attached to the rear of the Plate. The flat metal surface simply helps to Boost and Clarify the signal!



Think your parents are obsessive about your location? Just hope they didn’t tag you as a child! There have been cases of surgeons discovering mysterious Tracking Implants their Patients never knew about!



2.       Personal Experience



  1. Anonymous · · Reply

    Hello you have a cool website. I wanna say thanks for sharing this cool articles with us. Keep up this good work.

    1. Thanks, It really helps to know that the effort is being appreciated.

    2. Thank you very much!

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