Questions tagged [rfid]

Radio Frequency IDentification

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27 views

PN532 (SPI) how to get firmware version

I am trying to use PN532 for Mifare card reading on STM32F4. Before even trying to go forward I have tried to read firmware version to verify that all works ok and cannot do it. I am trying to base ...
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27 views

How to measure inductance (and more) of DIY LF (125kHz) RFID antennas

When winding my own coil two factors seem most important, inductance and serial resistance of my antenna. However measuring inductance doesn't seem that easy. Ideally I need an LCR-meter that is able ...
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24 views

Is there a difference between read range and read speed/sensitivity in LF RFID applications

If I want to read 125kHz tags but my antenna oscillates at 130kHz, read range will suffer given that the antenna has a low enough Q-factor to still excite the tag at 125kHz. My question is, is there ...
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56 views

My cellphone is acting as an RFID tag? [closed]

I bought a cheap keyboard emulating RFID (miFare) reader for my PC. I just noticed that the reader can 'read' my cell phone (Pixel 1 XL). Every read seems to return a different serial number. I can ...
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29 views

Ethernet cable react with anti-theft RFID gate

Yesterday I was leaving a shop, I had an ethernet cable in my backpack, and it reacted with the anti-theft gate, causing a false alarm. I was just wondering why.. I had also other cables (hdmi, power ...
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21 views

Passive RFID design assistance

I am looking for the correct RFID tag/reader system for my design. The general block diagram of the system is above. The requirements for the system are as follows: Passive tags of some form and an ...
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44 views

RFID reader technology

Hopefully this isn't too broad of a question, I will narrow it down the best I can. We need to add RFID tags to feeders on our pick and place machine, to determine that they are loaded into the ...
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56 views

Up to 25 meters range passive RFID?

In this document, we can read: Passive: Read range from near contact up to 25 meters about UHF RFID. This is impressive indeed. Which kind of passive tags can be found up to a 25 meter distance?...
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45 views

Have trouble designing antenna coil for chip receiver

I'm trying to wind a 125khz rectangle coil antenna for the AS3933 receiver chip. I calculated inductance using this calculator where parameters were: Loop Width:20cm Loop Height:14.5cm Wire Diameter:...
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93 views

I want to put a radio transceiver in the seatpost of my bike. Will it work?

I am a noob regarding electronics. I want to create a device for my bicycle using a GPS with an eByte E32 (a 1W LoRa SX1268 433MHz radio transceiver) and some batteries. The device will be in the seat ...
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24 views

FCC/ETSI conformance with backscatter

Do passive backscatter devices fall under regulations of FCC/ETSI? Suppose a system emits a 4W EIRP tone in the ISM band (conforming to FCC/ETSI regulations). A fully passive device backscatters data ...
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24 views

Pad disconnected from smd chip

I was trying to breadboard a circuit using 3-D antenna chip. I didn't have pcb board ready for it so I tried to solder jumper wires on the pads and then test the circuit by breadboarding. After ...
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49 views

RFID spoofer with extended range

I have recently found this tutorial online about making a simple RFID spoofer, using only Arduino, used paper roll, coil wire and some passive components. I thought it was pretty neat and decided to ...
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37 views

Can't run two RFID readers off the same 5V rail

I have a circuit consisting of an Arduino Mega2560 connected to a 134.2kHz RFID reader from Priority1Design. The RFID reader works fine by itself, however as soon as other components are connected to ...
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23 views

power decoupling 2 RFID scanners run by an arduino mega

I have an arduino mega 2560 hooked up to 2 Innovation ID-20LA readers, datasheet found here. My code works fine, as I have a single setup working perfectly. I don't know why the other setups don't ...
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132 views

Is this chip still usable?

I tried soldering jumper wires to my 3-D antenna, CAS143-47 and little bit of solder found it's way on the chip's body away from the pads. It was my first attepmt at soldering. It looks ugly and ...
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31 views

Limit of number of RFID tags

When I read about multiple (UHF) RFID tags I hear the issues about collisions, multi-path, interference etc. Assume reading time is not an issue and we can employ TDMA to read them sequentially. ...
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36 views

FDTD simulation for beginners using matlab

My previous posts are as follows: 1.Mitigation of dead zones when applying circular polarized antenna 2.Standing waves modes inside a cavity resonator 3.Visual understanding of EM fields within a ...
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59 views

UHF (868 MHz) RFID external antenna

I want to find an external antenna, to remove the box and just solder directly to actual reader board with a built-in PCB CROSS DIPOLE ANTENNA- see those 4 points in the attached image. I want to ...
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30 views

What approval is required for custom-made 125kHz LF RFID reader for sale in the USA [duplicate]

I have a custom-made 125kHz LF RFID reader which I want to sell in the USA. What approvals are required for sale in USA ?
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28 views

What is an equation that will show RF wave characteristics?

I want to show a RF wave on a spherical grid coordinate system. How can I show the RF wave when t = time and y = magnitude? I also want to show curvilinear coordinate transitions of the RF wave ...
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2answers
46 views

Why do LF RFID tags use near field and why is reading distance longer with UHF RFID?

Why do LF/HF RFID tags use the near field (magnetic coupling) and not the far field? Well, I guess it's easier. The two antennas can just be modeled as a "transformer" and power transfer is straight ...
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58 views

Can/will the Qi charging system damage LF (125-133kHz) RFID tags?

In the Qi standard, frequency is listed as 80-300kHz for the higher power application which is within the target(resonance?) frequency of LF RFID tags. So power transmission should be quite high for ...
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63 views

Mitigation of dead zones when applying circular polarized antenna

I would like to know if I used a circular polarized (RHCP) antenna inside a metal container as show in the configuration below will it reduce the dead zones, as compared to a linear polarized antenna? ...
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61 views

Searching for an RFID car key

I want to locate a lost car key. It’s a 2004-vintage classic metal transponder key (not just a fob as is used in modern “pushbutton start” cars) which uses the immobilizer system (125 KHz?) to ...
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2answers
23 views

Two Mifare cards: could one be readable and the other not?

I have an RFID keyfob which is used to access my building. The access is not otherwise authenticated (everybody just touches the door with the keyfob and enters) so I was wondering whether I could use ...
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69 views

Looking to make a large surface area 13.56MHz antenna with short range

I wondering about the feasibility of making a 13.56 MHz antenna that would occupy the entire rack of a shelf (5'x2'). The range would need to be small so that it only identifies entities that are ...
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1answer
32 views

Read T5577 tags with PN532 reader

I am working with adafruit RFID/NFC reader. This reader works with a PN532 chip. This chip is designed to read mifare tags (13.56MHz). I want to read T5577 tags. This tags works at 125 kHz. I am ...
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45 views

How do I get started on my RFID project (beginner)? [closed]

This is related to a recent, off-topic post I had linked here. I'm trying to make this post more for advice on my project, since I'm new to electronics and RFID and not entirely sure what I'm looking ...
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89 views

RFID reader sensitivity/read range - How does a “hard” ground increase sensitivity/read range?

I'm working with two RFID readers in my circuit and an arduino to control both of them. The whole thing is powered by a very cheap wall-wart Power supply at 12V which is rather noisy to begin with. ...
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2answers
98 views

NFC antenna connection to ground midway through loop

I'm designing a PCB etched NFC antenna. I'm confused about a design element I've seen in several production boards. I haven't seen this element explicitly discussed in any app notes or design guides. ...
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35 views

Electric field internsity of RFID loop antenna

We are going to export a fairly simple RFID product (Mifare, HF 13.56 MHz) to Japan and I am trying to figure out if we have to go through the full certification process or if we can register it as '...
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59 views

Do HF (13.56MHz) RFID readers need government approval? [closed]

If I were trying to design a product and added a RFID reader in it, would that RFID reader need government approval from the country I'm selling in? I believe UHF RFID readers need approval from each ...
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70 views

SPI ATMEGA328P does not send back on MISO

I am using ATMega328P and programming in Atmel Studio 7 and I am trying to initialize the SPI. I initialize it and send some data, checked with the oscilloscope, the data is sending on MOSI line but I ...
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120 views

Is it possible to confine radio frequency signal?

I would like to build a confined enclosure(like a 50cm cube box) to limit and perform RFID scanning only within the box, not interfered by the RFID tags laying outside the box. My intention is to be ...
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84 views

What data is typically stored on RFID cards and why?

I understand that all RFID cards contain a UID in their memory from manufacture, normally in sector 0. But they also have additional sectors for data storage, my question is what is some example data ...
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99 views

RFID reader can't detect blank RFID tag

I bought an Eval kit for an RFID module. The reader detects the card included in the kit just fine, but it can't find a separately bought, completely blank RFID tag. The reader is 13.56MHz and ...
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36 views

MFRC522 - Impedance control with External Antenna

I am a newbie into the world of RFID. For one of my upcoming designs, I am using the chip MFRC522 and an external antenna. The antenna is W7001. As you can see in the datasheet, It is mentioned that ...
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76 views

Is it possible to program a RFID tag like a microcontroller?

I am working on an RFID project. I want to be able to send specific messages between the reader and the tag or maybe perform my own protocols on it. Is there a type of tag that I can provide some sort ...
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49 views

What does the power EIRP mean

The South Africa regulations states that the maximum power to be transmitted is 4W EIRP. What does this EIRP mean here? Secondly when using the Friis equation: Power received(dBm) = Power transmitted ...
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31 views

Difference between an RFID module and evaluation board?

I get what a eval. board is, but what's a module? But also, why are HF RFIDs cheaper in eval. boards, but UHF RFIDs cheaper in modules? at least on Digikey.com
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Is there a difference between an NFC and RFID chip?

The other day, my friend said that he wants to write an app that uses the NFC chip on a phone to read pet microchips. I told him I was pretty sure that pet microchips don't use NFC, but he said he was ...
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38 views

MFRC 522 not working when using with relay module

I have a circuit which basically have to link up to MFRC 522 module, Arduino Nano and also the relay 2 channel module. See below for the basic schematic. simulate this circuit – Schematic ...
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3answers
328 views

External Antenna connection on MFRC522

New to RFID world. I am working on a Healthcare product. One of the feature includes authentication of patients which will be done through RFID reader MFRC522. Application schematic in the datasheet ...
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62 views

can aluminum foils increase the boost the range of nfc reader?

I have been working on a project where I have to read data from an NFC tag and store the information locally. Currently I have a range for the NFC tag of about 5 cm. The tags will be present inside a ...
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2answers
29 views

Ratio between RFID reader and tag antennas

If a tag's antenna (45mm x 75mm) is larger than the reader's antenna (20mm x 26mm), could this pose coupling problems when trying to read the tag? The reader functions correctly with tags similar to ...
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75 views

RFID link budget formula

I am attempting to design an RFID system. But before I do I need to simulate this system. I know I need to use the link budget equation to see whether or not the RFID tag will receive enough power to ...
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1answer
105 views

Measuring the orientation sensitivity of a UHF RFID transponder, where do the deviations come from?

I measured the orientation sensitivity of a UHF RFID tag using a Voyantic Tagformance Lite RFID test device. I rotated the tag along the 3 axes using a stepper motor and a rotating table. The ...
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95 views

How does this UHF antenna works?

I have a cheap UHF RFID antenna (9dB) like this : How does this kind of antenna work? There is no dipole? Why does the "L" at the bottom left of the disc have finer passages than others? I can not ...
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45 views

Is there a way to have the LED switch on after 10 readings or say a minute?

I am using Arduino for a RFID project where the LED must switch on after either 12 readings of the tag or 2 minute, the tag reading happen every 10 seconds. I can't seem to figure out a way to have ...