Hi everyone,
I don't know if I am in the correct category but Italian forum doesn't work...
Okay, so, I have a NFC tag which works at 13.56MHz. I've bought a RC522 Reader for Arduino. It'll arrive tomorrow.
But I'm not sure it will do what I need. In fact, the tag I have is very complicated, it's used in my mother's gym for write down how many times she go there. So values change when she put her tag near that reader.
So, hoping I've been clear, the problem is: does the RC552 reader allow me to view all that numbers that the tag have?
I know it's a EEPROM memory (24C02) and it has numers like the image I attached.
Surfing the Net I viewed projects for opening doors and so on.
I don't know if libraries like this >< can help me.
I admit I'm not very keen on Arduino, I've just started.
Thank you very much.
Hi,
yes I've thinking about it, but my reasoning was: if that machine can read the tag and modify it, why can't I? It's a simple EEPROM programmed by that company.
Well, you know more than me about this, but I am sure and I underline SURE the memory can be modified linking all numbers shown in the picture to a EEPROM programmer.
Sorry, I don't know much about this.
I have never see an rfid tag with an EEPROM in it. That chip has an I2C interface so if it is in a tag there must be some other processor inside the tag as well. Do you even know that the reader is an rfid tag reader? If so is it a 13MHz one?
These things are deliberately made difficult to change for security.
You could read that chip directly by wiring it up to an Arduino but I doubt the number you are looking for would be a single memory location.
Well, I think there's an antenna for the signal of course.
The only thing I know is: it works at 13.56 MHz frequency and it's an EEPROM.
I'm sure of these things.
Can I ask you another thing about this? You said it's difficult because of security. But their reader can change values on the tag as well, and I don't think it's a "special one". What's the difference between mine and theirs?
Thank you.
Okay okay, but password is not a problem, I don't want to do that.
I only want to know if is possible to read them.
Surfing internet I've found this:"Inside there are two coils needed to interface with the readers. When the memory comes within range of the reader is surrounded by a magnetic field carrying data and a stable frequency for the power supply of the EEPROM".
Sorry for the translation.
So do you think it's possible to read and write data?
Maybe not all data can be written, because I found some addresses of the memory are unlocked (the earliests, of course) but not the user data (the latests).
from memory its possible to programme a mifare card to emulate nfc protocol and it will read that but wont write to a proper nfc tag.
Nfc tags generally have no encryption and can be read and written to as its an open system
If you can find an nfc equipped phone then you could try that.
Its not 100% though as to make things worse there are some imcompatabilities between some nfc tags and the chipsets used in the phones.
Well, I didn't know the existence of a RC523 reader, and I haven't found anything on Google.
I hope I will read that.
Information are recorded on the tag, I'm sure of this.
You're right, it's not NFC, but the principle is that.
I've found some images of a 24Cxx memory similar to mine, bigger but it's the same.
There are two coils (47µH), which work as a transformer and generate a magnetic field.
These communicate with the reader across an amplitude modulation (protocol i2c).
Gioi:
You're right, it's not NFC, but the principle is that.
Its similar but the readers such as the 522 are designed for specific protocols and tags.
AFAIK none of them can 'talk' I2C but i have not checked.
There is a pdf document by NXP on the net somewhere which explains in detail.
Its 400 pages long though.
Okay, it arrived, I've connected all pins.
I've tried to change UID with the original examples library, but it seems it don't receive any signal.
I've tried to read UID and restore bricked UID, but nothing.
I attach the c++ file of the "change UID" example, my serial monitor shows only the first println command and doesn't go.
