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Tracking a person with RFID or similar tech

Discussion in 'Radio and Communications' started by van der brook, Jul 24, 2010.

  1. van der brook

    van der brook New Member

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    Hi

    Let me start off by saying, that I am a complete noob when it comes to electronics. I am a software developer by day and geek by night, but electronics is not my field by any means. I hope I am on topic here, as I found the forum by googling for forums about RFID.

    My stepdaughter has a very severe degree of autism, and is unable to take care of herself. On several occasions, she has managed to run away from us or her schools/institutions, and it has taken us up to 3 hours of intense search + police help to locate her again. All kinds of bad things can happen to her while she is gone.

    I want to be able to track her easily, if she runs away. Now here is my idea - it might be utterly useless or impossible - but it will get you an idea about, what I am looking to achieve.

    I am thinking, we give her a bracelet with some kind of transmitter (RFID?) that has a range of at least 3-400m, that she cannot take of (that means waterproof is a must). Then as soon as we find out, that she has run away, we get out a receiver/tracker of some sort - and we would be able to cover the entire area she might be in within 20 minutes in a car. As soon as we pick up her signal, we should then be able to pinpoint her location by some sort of directional tracking (not sure if that is the correct term).

    Is something like that possible? What would it require? Am I overlooking a much better idea?

    Real time gps tracking would be perfect, but I think the issues of battery life + size rules that out. Am I wrong?

    I hope for your assistance and advice.

    Thanks in advance

    Klaus
     
    Last edited: Jul 24, 2010
  2. Mike_2545

    Mike_2545 Super Moderator

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  3. TiagoSilva

    TiagoSilva Member

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    I was almost having to work with an even more complex project involving RFID tags to precise locate individuals within a space, resorting to the triangulation of each db value, signal deflections, etc, I'm also a programmer, a computer programmer. You can achieve what you need with some ease, you need an active RFID tag, that means that it is a RFID that requires an external power source (the common RFID tags use capacitors to charge up using the transmitter signal and then echo back the ID code using that stored energy). In your case I would recommend using an active tag around the 10Mhz frequency and use a matching receiver with an more (than usual) sensible antenna. That would be enough for some meters, say 100mtrs or so.
    But, the main idea of the RFID is not to locate objects/individuals but ratter to identify them!!! Of course we can always be creative, but a target location system using RFID (lets say, for more than one person) would be better.

    Bottom line, the stronger the amplifier stage on the RFID tag receiver, the more powerful the RFID active tag, the more sensible the antenna, the further the range gets!!! But it gets expensive like hell investing on this tech, are you sure this is the only way to do this ?

    You could always use a very small GSM module + a GPS receiver and a small micro controller, to send (from the target) and receive (on your phone for ex.) an SMS with the target position, by your SMS command or repeatedly in small time frames.
     
  4. dave

    Dave New Member

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  5. TiagoSilva

    TiagoSilva Member

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    The GPS could be switched on and off by SMS to spare battery life too... The bracelet could have a small solar panel or a small magnet inside a tube with a coil to extract energy from arm movement...
     
    Last edited: Jul 24, 2010
  6. TiagoSilva

    TiagoSilva Member

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    This is by far the best option you could have! It is also (fantastically) cheap. RFID gets a lot more expensive... GSM and GPS are expensive too... This is just what you are looking for!!!
     
    Last edited: Jul 24, 2010

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