Citat:
To sto si napisao, to nam prepricavas "znanje" iz vikipedije ili iz licnog iskustva, t.j. znanja koje si stekao baveci se tom materijom?
Iz licnog iskustva, npr. svaki dan u prodavnici kupis nesto sto ispod poklopca ili u ambalazi ima (pasivni) RFID tag, ne veci od male tracice zalivene plastikom... a to se sve cita sa onim "cudnim" vratima sa "dva stuba". Dakle, nikakve baterije, nikakvo napajanje, "mehanizmi"... to su prosti pasivni RFID tagovi, za svakodnevnu upotrebu. Koji se citaju, a da ne moras da ih dodtaknes ili jako blizu primaknes nekoj povrsini.
Kad bi slican pasivni RFID tag stavio nekom u ruku, a citace rasporedio po ulazima zgrada, prodavnica, autobusa, pesackim prelazima itd... ne bi bilo problema da se ta osoba delimicno prati... ali realno, svi imamo mobilni, tako da svrha pracenja i nije neka - jer je mobilni npr. mnogo laksi i precizniji nacin. Doduse ugradjeni RFID u ruku, bi bilo mnogo teze izvaditi (da se to ne vidi) i posle vracati itd. Recimo ima smisla staviti tag u automobilske gume i tablice (kao sto se vec radi) i onda ugraditi (lezece) citace na raskrsnicama, semaforima itd... tako bi mogao efektno da se prati auto (iako je user iskljucio mobilni, gps, stavio lazne tablice i sl.), gume su dovoljno blizu putu da i najloshiji sistem moze da procita tag.
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Ovo o cemu ti pricas je verovatno bullet proof verzija (sa naduvanim cenama) za vojsku, koja mora da izdrzi bog te pita sta, razne uslove i smetnje. Ono sto ja pokusavam da kazem, je da je tehnologija vec tu... mnogo prostija, jeftinija, i da to nikako nije cigla koja se kaci ispod tenka, vec nesto sto ce se stavljati na list papira, tako da ga ne primecujes. A da se vec danas, u svojoj grubljoj formi, svakodnevno obilato koristi u prodavnicama - gde apsolutno nije potreban kontakt da bi se tag ocitao.
Ono sto se danas proizvoidi:
Citat:
It depends on the type of RFID system being used. A high-frequency (HF) reader based on the ISO 14443 air-interface protocol standard, designed for short-range transmission, has a maximum read range of about 18 inches. An active RFID system can read tags from 1,500 feet away or more, as the tags broadcast a signal and the systems are designed for longer-range applications.
Even within one type of RFID, however, there can be a wide array of read ranges. A passive ultrahigh-frequency (UHF) handheld reader has a range of about 10 feet, while a model using a beam-steerable phased-array antenna can interrogate passive tags at a distance of 600 feet or more.
Keep in mind that the reader is only half of the story. A very small passive tag with a small antenna harvests less energy from and reflects less energy back to a reader. It, therefore, has a shorter read range than a tag with a much larger antenna. I have seen small passive UHF tags that can be read by an ordinary fixed reader at a distance of only 2 or 3 feet, and I have seen passive tags that can be interrogated at a range of 80 feet.
http://www.rfidjournal.com/blogs/experts/entry?10918
2-3 feet = 60-90 cm (dovoljno da te svaka bandera, ram od vrata ili semafor ocita)
80 feet = 24.384m
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Za registarske tablice:
Citat:
The UK-based vehicle licence plate manufacturer, Hills Numberplates Ltd, has chosen long-range RFID tags and readers from Identec Solutions to be embedded in licence plates that will automatically and reliably identify vehicles in the UK.
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The plates are the same shape and size as conventional plates, and are permanently fitted to the vehicle in the same way. But each e-Plate contains an embedded tag with a unique, encrypted identification number that is transmitted by the tag for detection by RFID readers. Multiple tags can be read simultaneously by a single reader at speeds of up to 320km per hour (200mph), up to 100 metres (300 feet) away.
http://www.secureidnews.com/ne...lates-to-identify-uk-vehicles/
[Ovu poruku je menjao Otto23 dana 22.01.2015. u 04:31 GMT+1]