RFID over distance

Projects General Guidance
1

I don't know much about RFID nor antenna design, but a bit of googling has lead me to believe this project may be feasible and I'd love a bit of input.

I'd like to be able to detect an RFID crossing a plane that may be up to ~15m wide (think a nice 3 lane road). The only constraint is that, like a road, I could only place antennas on either side or over the plane so as not to hinder movement across.

Any feedback, even some reference material would be fantastic!

2

I'd like to be able to detect an RFID crossing a plane that may be up to ~15m wide

Nope. Not going to happen. RFID chips are passive devices. They do not work at those distances. More like 1.5 cm.

There are active devices that can be read at those distance, but the readers are not cheap, and the devices are much larger than an RFID tag.

3

ive seen and used a rfid scanner that goes as far as about 15ft.. if was built into a commercial rf gun and is used with that black igps pallets.. 15m is much farther though :-{

4

Actually it is possible to read the presence of RFID at distance. I am not sure the types typically advertised and used with arduino. I have a friend who holds a patten for using RFID on vehicles and aircraft for tracking on the ground. The method was similar to what you are describing. Now were to find that type of RFID devices I have no idea. I can say that stores like Best Buy I believe use RFID for tracking merchandise that leaves the store before being deactivated.

5

Ok, so let's forget passive RFID - how about active?

6

Do you need someone to google that for you?

7

PaulS:
Do you need someone to google that for you?

Haha, take it easy - I am reading away... I'm just asking in case someone else perusing may have attempted something similar in the past and could provide some useful resources that they have used be it components or articles, as I'm sure you can imagine there are a bajillion results and a lot of data to digest simply to figure out the direction to head in. Even tidbits of information, keywords, help vastly especially for the sake of posterity.