Extend range for MFRC522 RFID Reader

You do not say what tag you are using.

Mifare crdit card size tags generally will read through a door.

The keyfob ones don't.

oh sorry, i forgot...

I tried both and i´ve set antenna gain to maximum. It depends on the size of the reflector and distance to the antenna. I used a copperplate 5x10cm...

i have experimented with several of those modules.

Read distance can be somewhat variable.

FlyingNautilus: Yes it is. You only have to remove the soldermask from the antenna (near to C11 and C10), destoy the connection to the antenna (in back of the soldermask) and finally solder the new antenna on the place where you removed the soldermask.

Hi, I'm not trying to extend the range but am looking to add a very small, very simple external antenna for a project that demands a tiny footprint. Can I connect an external antenna in the form of a simple tank circuit across the TX1 & TX2 pins? I only need to read cards, not write to them ... and distance is not a factor. This means that the TVSS pin (gnd) would be left unconnected.

I've sourced a coil from coilcraft.com designed especially for Z axis RFID applications @ 4.7uH. I've calculated a tuning cap value of 29pf to achieve ~13.6 mhz resonance. The arduino pro micro's pins have parasitic capacitance of ~10pf so I had planned on trying a fixed cap of 10pf in parellel with a 10pf variable cap for tuning. Has anyone tried this or know if this configuration will work with the RC522 IC ???

If the TVSS pin MUST be used in the antenna circuit could someone please post a simple example? For a read only situation I was hoping to simply connect the tuned tank circuit (fixed cap/variable cap/coil) across TX1 and TX2. I guess I could wire 2 coils in parallel on each TX pin to get the equivalent inductance value if TVSS is required...and have plenty of the coilcraft samples - http://www.coilcraft.com/pa6512.cfm

Just as a follow up, I used this forum post and the image where to cut the traces in a successful test.

I needed an antenna some 20cm further than the module and I used some thin wire (sorry but I am not completely sure of the diameter of the section, most likely 0.25mm ). The antenna seems to resonate with 5 turns of some 6cm diameter.

I attach a pic as a reference. The distance of the RFID cards goes up to 5cm but exactly on the center and very flat. Closer ranges, like 2cm, the angle and position are not so sensitive.

Hope this helps.

Sorry, new to the forum... I tried already 10 times attaching the pic but with no luck. Use your imagination :o

Anyone knows how to increase the card read-write distance upto 10cm+ ? if you help, i will be happy.

There was a thread here a while back where someone doing the same thing through a door reported an increase in read distance by placing a metal reflector behind the board.

todocono: Sorry, new to the forum... I tried already 10 times attaching the pic but with no luck. Use your imagination :o

Try reading this How to use this forum

We do our best to hide it by putting it as a sticky post in EVERY section of the forum, you cannot make a post without willfully ignoring it.

Realise this is an old thread but it still tends to come up in search engines when you're looking to increase range of an RC522. I maxed the gain through software but it still wasn't quite enough. From the datasheet, limiting value for the power supply on this device is 4V. I can confirm that running at 4V rather than 3.3V increases the range somewhat and may be sufficient to penetrate whatever material is in the way. Obviously running at the limiting value continuously isn't a great idea but needs must. For convenience I'm running just above 4V by sticking a silicon diode in series with the 5V output of an arduino. Please note if you fry your RC522 doing this that's your own fault for listening to strangers on the internet.

Been trying to extend area of RC522 and saw this for sale:

13.56MHz RF Module 8cm External Round Antenna Coil 12.3cm Diameter

Looks like it’s got built-in caps and coil tuned for 13.56.
But it’s got 6 pin “J2” so not sure how to wire it to RC522
Any ideas?


The 13.56MHz Mifair cards work on two frequencies. The 13.56MHz is the excitation frequency and provides the power to the tag and also sends data to it. However the tag transmits back at exactly a sixteenth of this frequency. Therefore that coil is two coils in one. The higher frequency coil, that is the shorter one should be connected back to pin 8 of the chip. The longer coil, the lower frequency, should be connected back to pin 7.

See attached application note on RFID antenna.

78010.pdf (280 KB)

Forgive my ignorance but i'm not sure how I could connect this to pins 7 & 8 of the chip. The RFID-RC522 has the chip already built in and it looks like pins 7 & 8 don't have any connection and the built in antenna is on pins 10 11 13 16 17. Mifare RFID Reader/Writer 13.56MHz RC522 SPI The external antenna pictured has 6 pins, so it's not clear how it should be attached to the board (and whether the built in antenna needs to be disabled somehow)

Forgive my ignorance but i’m not sure how I could connect this to pins 7 & 8 of the chip.

Sorry, for that chip package it is not 7 & 8.

This is the typical schematic. You will see 16 & 17 are the RX side and the rest are the TX side. It will not be easy hacking off the parts on your reader and attaching this coil.

Dear All I'm a student.

At before my RC 522 working well, but now isn't working. I think the problem in hardware. Any advise for me to test it ?

Please read this:- How to use this forum

And then start your own thread.

Hi all,
I wish to rebuild the Petsafe Petporte cat flap device. The one I have does not register my cat’s chip. So I’m thinking of using the RC522 with an Arduino Pro or similar. The only thing is that i’m wondering whether the range of the RC522 will be enough so like other members here I was thinking of attaching the RFID antenna of the Petporte device to the RC522 by cutting the wires to the pcb antenna and soldering on the 2 wires of the Petporte antenna. Can this work?

What part of:-

Grumpy_Mike: Please read this:- How to use this forum

And then start your own thread.

Are you having trouble with?

rencius: Maybe someone knows, is it possible to solder external antenna on RC522? If yes, then where? I already tried some different spots to solder it, but i'm not sure why it doesn't work.

It is very difficult if not impossible.

Near field tag readers at 13.5 MHz are designed to operate over a 5 CM free space range or thereabouts. The presence of wood in the field (such as a door) which contains moisture will reduce that.

Tuning the aerials requires some rather specialised expensive equipment. Other systems at lower frequencies give longer range , such as those used for security tags in supermarkets.

Most acess systems i have seen do not work through door. The detector is an externally mounted device made of thin plastic.

Since this conversation is still appearing on search engines and to help those who are looking for an RFID receiver that can handle distances of 10cm+, SparkFun has one that is rated up to 18cm here: https://www.sparkfun.com/products/11828 I'm not sure how going through a material such as wood on a door would affect its range, but for the price it is the best I have found.

Except for the fact that that product is a 125KHz RFID reader and not the 13.56MHz cards that the OP was asking about.

You can get a much longer range with the lower frequency reader. That product has a read range of 180mm where as the 125KHz I designed has a range of 18 inches, and with a suitable coil could exceed 6 feet.

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