Questions tagged [nfc]
Near Field Communications - In antennae theory Far Field radiation is that RF energy that gets transmitted, Near Field is the RF energy that typically does not propagate , unless it is intercepted by a special antenna. It is used to transmit signals over short distances without transmitting widely, it is used in wireless communications for very short ranges on the order of meters and is harder to intercept because you have to be close.
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Easiest way to detect objects using DIY materials
I want to build a Scrabble board that detects tiles placed, mainly as a one off challenge and learning experience (i.e. not a commerical product). I haven't started building yet: I'm trying to work ...
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RFID antenna measuring resonance frequency does not cover the theoretical value
I am looking to design a custom RFID antenna which operates at 13.56 MHz. I have designed the antenna using the NFC Design tool (link). Please see the parameters below:
Figure 1: Antenna parameters
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Does the minimum value of the S11 (return loss curve) at the resonance frequency depend on the resistance of the antenna?
I was trying to fabricate a flexible NFC antenna. Initially, I fabricated my design on a copper PCB. It worked perfectly fine with my NFC chip and facilitated NFC communication. I observed its S11 ...
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NFC Antenna Design for ST25R3911B in HFSS: Seeking Assistance with Antenna Parameters Extraction
I am currently working on antenna matching for an ST25R3911B NFC reader IC and using HFSS for simulation purposes. STMicroelectronics provides an antenna matching tool, and I am planning to use a ...
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NFC antenna design / Simulation
I'm looking for help with my NFC (13.56MHz) antenna design. I am using a NXP-NT3H2111 NFC IC and so far I have read through the application note and other research papers available online to try ...
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NFC antenna design - moving from rectangular to circular
I'm working on a design using an NXP PN7150 NFC chip with PCB antenna. My initial prototype used their online tool for the antenna design, to generate the values for the matching network, however this ...
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How many coils does an NFC tag contain?
I'm trying to wrap my head around NFC tag inner workings. In particular I'm curious whether different coils are used for harvesting energy and to transmit data. This random NFC tag IC datasheet I ...
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NFC module commands/ TagLostException
I am trying to send commands and image data to an NFC module connected to an e-paper display and keep getting TagLostException, probably meaning the command is wrong. I have asked this question on ...
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PN532 RFID Reader IC taking up 4mA even when there is no power applied
I have designed a custom PCB for one of my side projects. PN532 is interfaced with ESP32 over i2c. Goal is to have the system consume current in uAmps range when in deep sleep. I put ESP32 in deep ...
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Disable NFC tag so it does not trigger reader
Is there a way to disable (kill) the NFC tag so that it doesn't trigger the reader. Without physical intervention.
My goal here is for the smartphone not to get triggered by a disabled NFC tag. ...
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How to calculate the size of the goldcap in energy harvesting?
I want to build an NFC-transponder (NFC chip: ST25DV) which is powered over energy harvesting. How could I calculate the size of the goldcap (supercapacitor) or maybe a normal tantalum capacitor to ...
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How can I make a double-sided NFC card, where the two sides read differently?
I'm trying to create a double-sided NFC cards, where the two sides read different things. So depending on which side you hold onto your phone, you get a different result. I've tried with a sheet of ...
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Are those components mandatory?
I am building this circuit for an NFC component ST25R95 on a small PCB.
I am wondering if I can disregard the marked components on the power supply (inductors and capacitors for filtering.) These ...
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mfrc522 Arduino library -> RFID ERROR: PCD_Authenticate() failed: Timeout in communication
I'm trying to do a project using RFID tags to store information to be retrieved later with another device. Kind of a storage memory.
I've bougth several tags which I can write and read with several ...
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Impedance match an NFC antenna to 50 Ω
I have a hard time understanding how I can impedance match a homemade NFC antenna to 50 Ω.
My antenna is designed by calculating the inductance based on the dimensions, windings, and so on.
R_ant is ...
