Reading with Arduino

Question

Hello,

I have RFID 13.56 MHz / NFC Module for Arduino , I have tried to read 3 cards at the same time and at the serial monitor I have get the UID for the 3 cards .

is that reading at the same time or just the module has read one after the other ?

Thx

Rita

mcb1 · Accepted Answer

I covered some basics here.

http://www.element14.com/community/community/designcenter/explorenfc/blog/2015/02/18/nfc-what-is-it

How does it work.

Contrary to popular belief the tags do not transmit.

The reader sends out a signal at the designed frequency (usually 125 KHz, 134 KHz, 13.5 MHz) and when a tag is within range it captures that energy.

This provides sufficient energy to power the chip inside which then will short the antenna in a particular manner.

The shorted antenna will detune the readers antenna, resulting in a difference. (a shorted antenna acts like a large metal object)

The reader electronics will translate that pattern of 'shorts' and 'non-shorts' into data.

How the reader handles the resultant data depends on the design of the system.

These tags are referred to as 'passive', and for some inventory control an 'active' (powered) tag can be used.

Because these tags are passive, you won;tbe able to read more than one at a time.

Mark

Robert Peter Oakes · Answer

RFID, easpecially the once we get for use with Arduino etc can not read at the same time, it would be one after the other, if you present all three at the same time, you will be lucky if it reads just one of them as there all on the same frequency and encoding

Peter

clem57 · Answer

Or throw a message to user saying "too many cards, try one at a time" Clem

Reading with Arduino

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How does it work.