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Topic: RFID usage for home application (Read 6906 times) previous topic - next topic


Hi all,

I'm newbie :( and I'm not sure about whether this topic is true for my question.

Our problem is that, we need RFID reader and Tags that are able to work with at least 1m (100cm).We searched web sites and products but we have not found, there are only some alternatives but they work only in very short distance (10 cm or 20 cm). We need your assistance and guidance.

Thank you..



Nope - I have never seen any RFID tags that can work that far - you're probably better off with low power RF.


Thanks for your answer, we are planning an application which is about home reminder system. The reader will be located near the door, and person have something that RFID tags located before such as keys, wallet etc. When person gets closer to door, reader reads the tags and reminds items that forgotten (systems like in the supermarkets).

We need a system that is able to work at least 1 m range. From your ideas, these range  readers are expensive, am i right?

Under these conditions, what do you suggest, what type of hardwares do we need??



There are reported to be varieties of RFID where hundreds of tags embedded in consumer products and stacked on a pallet can be read at a distance of perhaps a few meters. This is reputedly used in inventory control and warehousing in large retailers (WalMart, et.al.) But that is specialized (and EXPENSIVE) technology that is not generally available to amateurs and experimenters.

True - I have seen those but as you say - very expensive.


From my personal experience with the RFID badge readers at the office, I can tell you that they are easily confused if you have more than one RFID tag passing through the portal.  The problem is that RFID tags are VERY DUMB little devices. There is no practical way to tell them to "take their turn" in the queue so that you can read them all. It is much like asking a group of children what flavor ice cream do they want. They will all reply concurrently in a caccaphony of information which is useless en masse.

Frankly, I don't know how they manage that in those application where they read hundreds (or even thousands) of RFID tags on a pallet. I presume that is why it is VERY EXPENSIVE.  And that is why I suggested that it may not be a practical solution.  Even the application of implementing RFID tag reading at the finish line of a foot-race is filled with problems that are only managed by extraordinary measures. I continue to believe that it is not a practical solution.

I'm totaly agree with your ideas, they seem to be meaningful. After all these brainstormings, what type solutuions (including hardware etc.) would be suitable for our project, what are your suggestions.

Thanks for your great assistance.


It doesnt seem to be suitable for our project, because person can put his wallet into different place each day, also we planning a system that new materials can be added into reminder list just locating a tag and defining them into system.

I think it isnt hard too much to establish.


Mar 18, 2011, 10:19 pm Last Edit: Mar 18, 2011, 10:22 pm by davutcavdar Reason: 1

Yeah, that is how I kept losing my keys until I put a hook by the door.  If I don't put my keys and glasses and (RFID) badge right there by the door, I will never find them again. :-)

Yes, that is an easy thing to do, also.  I am currently teaching a class on how to design just such a system, but we are using barcode.  The problem of scanning multiple RFID tags, plus the problem of scanning any RFID tag at a distance are the show-stoppers here, at least as I see it.

We dont aim to find lost objects in home mainly, our plan is focusing on reminding objects that defined into system before going outside of home, if they are not read by RFID reader. These objects are not too much, they are only 4 -5 max 10 ( wallet, keys, cell phone etc), because of that, the proability of becoming a jam would be low i think.

These all are just my assumptions, i am still open your suggestions about hardware or any kind of solutions.

Thank you..


Yeah unless you want to integrate an antenna into a door frame then I think you might have issues with RFID - if the devices could be powered (even just by a coin cell which might last a month or so) then you could so simple wireless and some fancy power management on an ATtiny or similar. Having 4 or 5 items per person with a battery device might be a bit much...


they are only 4 -5 max 10 ( wallet, keys, cell phone etc), because of that, the proability of becoming a jam would be low I think.

I think you meant "I hope", rather than "I think", and I'm afraid I have to tell you that you will hope in vain.

With a (new) $35 reader from a reliable supplier, if I had TWO tags in a plastic bag, about 4cm from each other....

a) They had to be within no more than 5cm of the reader to be picked up reliably.
b) Presenting both together would result in one or the other... more or less at random... being read. The reader then (good design, even if it isn't what you want) won't read another tag until the one it has "seen" is taken away.

Perhaps what your friend needs is simply a list by the door... "Have you got? Keys? Wallet?..."

(Not as much fun, I know!)

Now... if you want them to PROVE they have those items, that is fairly easy to set up... but will be a pain for the user. Each item will have to be held close to the RFID scanner, separately. THAT could be done.

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