I'm not thinking of anything. I know exactly what I am talking about because I sell, design and install security systems all day long.
NFC is a set of technologies for smartphones, that uses standard RFID frequencies.They can typicaly read 13.56Mhz RFID which is smartcard technology (Mifare, desFire, etc...) found in newer access cards and bank cards.
RFID is a generic term. Specific technologies and frequencies are whats important.
Regardless of any of this, read your link carefully, it doesn't say that you can read a tiny passive tag at 1-3m.
- To read at more than a few inches you need something in a high frequency range. 433mhz to 2.4ghz.
- Your tag needs to be relatively big (2-4 inches, like these stickers https://www.awid.com/index.php...)
- It has to be positioned just right, wont be reading it sideways
- The reader needs some good power and a good size (https://www.awid.com/index.php?option=com_content&view=article&id=537:lr-2000&catid=979:readers-lr-avi&Itemid=205)
This can be increased if the RFID tag has a battery, then however it is no longer Passive, it is active. And thats a hole other ball game.
Only reason RFID tags put on clothing in stores can read from several feet is because the readers (those large SENSORMATIC devices at the exits) have copper rings that are 2-5 feet high) which increases the read range of the tiny RFID chips with tiny cooper rings.
Also, you wont be doing inventory with RFID chips that read up to 20-30 feet. That would be crazy expensive RFID chips on your cheap merchandise and also, you wouldnt be able to figure out where your inventory is, as you can read it from across the room. Doesn't make much sense.
So... basically, my point was just, you cant have a tiny key chain as an RFID reader, read tiny chips, on tiny objects around you. Just wont work.... with currently technology.
Unless you use tiny batteries :)