Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Don't rock me but I thing RFID stand's for Radio Frequency IDentification.
Ok, back to the technics:
There exists mainly 2 types, 1. with a frequency of 125kHz 2. with a frequency of 13,56MHz
That means that the host/reader send out a carrier and the RFID-chip will modulate that carrier. Voila we have a communication from the RFID chip to the host. This is a readonly connection!!!
Ok, we assume that we want a readwrite connection, then the host has to modulate the carrier also, this is done with ASK. The RFID chip can answer in the common way. Read-write is also done...
But know, we think about a application where we have a security key on a RFID-chip, and we want to use that security key to get access to a "special, special, sp..." computer... , then we think this highly special security key, will come over the air and everybody with a RFID-Reader can read it...
Ok, here comes the time to take a look at security RFID-chips like HITAG, MIFARE and so on. They will encrypt the communication between the Reader and the RFID-chip also.
BTW there exists also other implementations to avoid collisions in multi tag(RFID) applications, but I hope this short introduction will help you.
Recently we designed spiral "antenna" for RFID transmitter @ 13.56MHz.
I've used "" because antenna is very small compared to wavelength and the detection occurs in reactive fields. Input power is few watts!
I saw it in action during the testing and it's really nice.
You have box connected to antenna and to PC where you have installed small application. Every time you move the receiving chip close to RFID antenna, number of the chip appears on PC screen.. Detection distance is around 10cm which is sufficient for the specified application.
I have done some experiments trying to implement RFID in range 125 Khz.
I will tell you:
- with an antenna Accura GP20 10cm diameter aprox. I read tags type glass 13mm in the distance of 10 cm.
- with an handheld device MINEC 4x I read and write tags (glass type 13mm or disk 50mm) only if I touch the tags with the device (0 distance of reading/writing).
Now I am trying to buy an antenna of TECTUS to connect my Palmtop using USB port. This will be the most cheap option for implementing RFID.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
