Re: [mh] CheaperRFID - feature requests?

[Brent D. <br...@de...>]

There are two "real" types of RFID, passive and active.

As I understand it, both "real" types of tags wait for a reader to  
send a query signal, and then respond to it with their id/information.

The CheaperRFID tags constantly broadcast their id every 2.5 seconds  
or so, so there is no query from the receiver. This allows the  
receiver to be just a receiver, and not a transceiver.

Active RFID ("real" or Cheaper :) has much longer range than passive.  
I thought passive was limited to really short distances, like 1 foot  
or less from the receiver.

I understand your concern about the batteries, but all active tags  
require power of some kind. The advantage of the CheaperRFID tags is  
that the batteries are user-replaceable. The few commercial systems  
I've seen don't even offer replaceable batteries. Once the tags power  
supply runs out, they make you chuck the tag and buy a new one. I  
dislike disposable technology a lot more than I dislike disposable  
power (batteries). Of course, that's the commercial solutions way of  
making you come back to them for the rest of your life...sigh...don't  
get me started...

Brent

On Sep 15, 2007, at 9:55 AM, Cliff Savage wrote:

> Hi Brent - Thanks for the education about RFID! But there's
> something I don't understand. I thought RFID tags were excited
> by the radio waves and as such - do not require a battery.
>
> The little RFID strip on my goods at the store do not
> require batteries (I think...but am I wrong about this?).
>
> Do all RFID tags require batteries?
> I hate battery replacment...wall worts...dongles....because
> these things detract from ubiquity.
> Maybe there's a couple different kinds of RFID tags?
>
>
>
>
> Brent DeShazer wrote:
>> Well, I think you have it backwards a bit, unless I'm
>> misunderstanding what you're saying. It's the receivers which are
>> tied to your PC, and they don't have a power/distance rating. Only
>> the tags, powered by either batteries or your car power, are rated in
>> terms of 8 or 40 meters and they do not connect to the PC.
>