Use RFID to light up an LED

Discussion in 'The Projects Forum' started by ece109, Jul 30, 2012.

  1. ece109

    Thread Starter New Member

    Jul 30, 2012
    1
    0
    Hello.
    We are working on our thesis.
    Actually it's not yet our thesis proper. It's a subject called methods of research, and our professor wanted us to make a basic Chapter 1 of the thesis. This is not yet our final thesis, thus the thing we are working on is solely by words and not yet on making the actual device.

    How the deivce should work:

    The device, which is an RFID detector, would be able to detect and signal a tag at least 20 meters away from it. The RFID is selective, meaning for example the I.D. will have different colors. This day it will only detect blue I.D.'s so basically, it wouldn't activate I.D.'s beside blue.
    It's parallel to a wireless car entry, wherein as you push the button on your car key, the doors of the car will unlock and some light from the car will light up.

    Question:

    1. will this utilize electrical relay in order to activate or light up the led on the I.D.?

    *I'm sorry if we are nob when it comes to this. As I've said, we're doing this as practice for chapter 1 of our thesis. And to be honest, we've not yet taken the subjects likely to help us in this one.
    Thank you! Anything is appreciated! :)
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,126
    3,048
    RFID at 20 meters will be VERY expensive, although at least possible. Lighting an LED will be the least of your concerns.

    A relay is not usually needed to control an LED. A single transistor or many logic ICs can control an LED directly without needing a relay.
     
  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Almost all RFID tags do not have built in power sources, they get "power" from the RF signal from the RFID interrogator circuit (The tag reader), if you want to light an LED mounted on the tag, I'm sure it is feasable, but you will have to design an energy harvesting circuit to "harvest" some of that RF energy, store and use it to light the LED... or use an Active Tag circuit, which usually has a lithium battery that can last for years (depending on use)

    take a look at these by this manufacturer, they have passive and active RFID tags..... http://www.synometrix.com/RFID_All_Tags.shtml
     
    Last edited: Jul 30, 2012
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