Roger Grimes on Why You Do Not Need to Worry About RFID Blocking Wallets
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@coliver said:
@johnhooks Doesn't EZPass (or any of the toll system) basically use the same tech with power-less devices and powered readers?
Yes, and they get some huge distance. And that's the distance at which you can READ it reliably. You can IDENTIFY one from many times that distance.
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@coliver said:
@johnhooks said:
A lot of stores use them to track inventory on the floor also.
I've seen that at Best Buy and the B&N on RIT's campus had those on most of the books. I think one of the professors (or maybe B&N) were trying to do an instant tally/checkout implementation.
German grocery stores have been doing that for over a decade. NTG was looking at stuff like that in the early 2000s to replace our medical bar coding systems.
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Alright if they've got "active" (battery powered) stuff and they call it RFID that's a lot different than passive (chip only).
Passive / chip only stuff is at best a meter or two (with a huge antenna like grocery store exits) - typically less than 10cm for stuff like bank cards, passports, etc.
Note: I don't think it's "RFID" anymore if you put a battery on it. Then it's just a bloody radio lol. And fair play I suppose, "Radio Frequency IDentification" but really the whole thing was supposed to be a passive reflector that lit up a specific frequency when pulsed by an antenna.
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@scottalanmiller said:
@coliver said:
@johnhooks Doesn't EZPass (or any of the toll system) basically use the same tech with power-less devices and powered readers?
Yes, and they get some huge distance. And that's the distance at which you can READ it reliably. You can IDENTIFY one from many times that distance.
No, EZPass is not a powerless system. they have batteries. That is how they get the range they get.
Powerless RFID is very short distance. The theoretical max range is only 5 meters to begin with under perfect conditions.
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@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
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@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
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Ah well that makes sense..
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@scottalanmiller said:
@MattSpeller said:
@scottalanmiller said:
The problem is that when kids walk home creepers can stalk them without being visible to the kids themselves.
The range of RFID is really short (centimetres). Essentially you'd see the kids long long long long long before you got an RFID blip.
Oh now, it is very long. Even in the 1990s the VNC team at Cambridge could be tracked anywhere in the building with them. I know the ones in our car go like a hundred feet or more. I know that grocery stores have them that go ten feet or more.
You all are working on getting me started on the things you can do with software defined radios, that you can pickup for $25 on ebay. I might not be able to reliably read an RFID card from a long way away, but you better believe I can get a response. Remember the people that got bluetooth working from a mile away? It really isn't that hard to do if you can do a little bit of math.
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@JaredBusch said:
The theoretical max range is only 5 meters to begin with under perfect conditions.
With an antenna the size of a garage door pumping out a boatload of RF... yeah I could see 5m
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@travisdh1 SDR is going to be huge and do some fun stuff in the next few years. Makes me want to go back to school!
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@MattSpeller said:
@travisdh1 SDR is going to be huge and do some fun stuff in the next few years. Makes me want to go back to school!
Just get back up to speed on your trigonometry and you should be good. Things won't get extremely complicated until the new fractal antennas get popular.
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Here is a simple summary for anyone who does not know.
https://www.rfidjournal.com/faq/show?139
@rfidjournal.com said:From how far away can a typical RFID tag be read?
The distance from which a tag can be read is called its read range. Read range depends on a number of factors, including the frequency of the radio waves uses for tag-reader communication, the size of the tag antenna, the power output of the reader, and whether the tags have a battery to broadcast a signal or gather energy from a reader and merely reflect a weak signal back to the reader. Battery-powered tags typically have a read range of 300 feet (100 meters). These are the kinds of tags used in toll collection systems. High-frequency tags, which are often used in smart cards, have a read range of three feet or less. UHF tags-the kind used on pallets and cases of goods in the supply chain-have a read range of 20 to 30 feet under ideal conditions. If the tags are attached to products with water or metal, the read range can be significantly less. If the size of the UHF antenna is reduced, that will also dramatically reduce the read range. Increasing the power output could increase the range, but most governments restrict the output of readers so that they don't interfere with other RF devices, such as cordless phones. -
I like that last part - increasing power could increase range, but the gov't restricts the output.
Since when do criminals care about the law?
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@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
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@scottalanmiller said:
@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
Mine lasted for 8 years and then I got an email that they were sending out a replacement and I need to return the old one. Performance has been steadily degrading on mine for the past 6-8 months, to the point where I would have to inch through the EZ-Pass lane for it to read. Makes sense that it is a battery then.
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@scottalanmiller said:
@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
It varies based on manufacturer and usage. The unit is normally passive. The battery is not always used. The battery is only needed to provide a strong enough signal in response to the pulse.
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@scottalanmiller said:
@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
Yeah - years .. I have no idea how many. I have one for my yearly trips to Chicago. It's at least 5 years old now. I expect to have to replace it at any random time in the future now.
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@JaredBusch said:
@scottalanmiller said:
@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
It varies based on manufacturer and usage. The unit is normally passive. The battery is not always used. The battery is only needed to provide a strong enough signal in response to the pulse.
This is how car fobs work.
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I am pretty confident that we bought ours in PA in 2006 when I was commuting to and from NJ while living in NY (PA was in the middle, you see.) So exactly a decade now. We still use it. It has been out in the car in the Texas heat for the last six years.
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@Dashrender said:
@scottalanmiller said:
@JaredBusch said:
@DustinB3403 said:
@JaredBusch there is a battery in the units that the customer takes with them in the car?
I've never seen where those units come apart to provide a new battery.
They don't. You have to replace them.
How long do they last? I feel like ours is over a decade.
Yeah - years .. I have no idea how many. I have one for my yearly trips to Chicago. It's at least 5 years old now. I expect to have to replace it at any random time in the future now.
Illinois uses I-Pass and is a separate network than EZPass but the units are compatible.
I-Pass units have an expiration date clearly printed on the units themselves for this reason.
