search

mxgxw / MFRC522-python

A small class to interface with the NFC reader Module MFRC522
GNU Lesser General Public License v3.0
521 stars 419 forks source link

Adapt Antenna Gain #30

Open tdullers opened 7 years ago

tdullers commented 7 years ago

Hi

Any clue on how to adapt the receiver gain in your example ?

espenoh commented 7 years ago

Not sure what you mean by "adapt", but you can control the antenna gain using the RFCfgReg, as documented in the datasheet (9.3.3.6, page 59).

Something like this in MFRC522_Init: self.Write_MFRC522(self.RFCfgReg, (0x07<<4)) should give you 48 db (max) gain.

tdullers commented 7 years ago

Hi,

yes that is exactly what I meant ! So, is it as simple as editing MFRC522.py in your example and adding this line ?

def MFRC522_Init(self): GPIO.output(self.NRSTPD, 1) self.Write_MFRC522(self.RFCfgReg, (0x07<<4))

espenoh commented 7 years ago

Yeah that should work.

I did some testing with this a long time ago, with little notable effect. Though in retrospect I think that was due to the antenna being mounted a bit too close to the ground plane of a PCB I had in the same enclosure (which definitely worsened the reception). Feel free to report back if you're seeing any noticeable change.

tdullers commented 7 years ago

OK, I need to do some more controlled testing but some first tests showed that with antenna set to maximum gain I could a small bracelet tag to read reliably with a 1 cm acrylplate in front of the rfid reader, without even touching the plate, with normal gain I could only get that to work with a 2-3 mm plate. With a normal rfid card tag I even got reliable signals with a 4 cm acryl plate above the reader. Will let you know when I have some more controlled results. However the RC522 seems a very solid reader, for sure compared to some commercial solutions that do often cost a few 100 usd,.... 

Sent from my Samsung Galaxy smartphone. -------- Original message --------From: Espen notifications@github.com Date: 7/25/16 00:18 (GMT+01:00) To: mxgxw/MFRC522-python MFRC522-python@noreply.github.com Cc: tdullers dullerstijl@gmail.com, Author author@noreply.github.com Subject: Re: [mxgxw/MFRC522-python] Adapt Antenna Gain (#30) Yeah that should work.

I did some testing with this a long time ago, with little notable effect. Though in retrospect I think that was due to the antenna being mounted a bit too close to the ground plane of a PCB I had in the same enclosure (which definitely worsened the reception). Feel free to report back if you're seeing any noticeable change.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

Liriel commented 7 years ago

totally works and increases the distance significantly from which the tags can be read!

guleus commented 5 years ago

Hello, just somehow got to your cool module so i thought i ask you. I bought some really cheap MFRC-522 reader/writers for my raspberry pi RFID project. Now i started testing the things, but was really disappointed by the distance of reading the passive tags (<1 cm) What i want to do is to achieve reading tags with a raspberry in a distance, lets say 0.5-1 meter and through clothes Do I need to get an antenna a differenet reader? Any good suggestion. How far does your reader read and trhorugh clothes too?? Thanks a lot

Liriel commented 5 years ago

Hi,

I am afraid I don’t have had a very good experience with the module either. It seems that small or bent tags are especially hard to read and not very well supported by the module.

What works well are Cards and those keychain tags that are given away with the tag. I can read them from like 3cm or so.

You probably need a completely different hardware (antenna and tags) for your requirement, like the anti theft gates you see in a supermarket.

HTH :)

From: guleus [mailto:notifications@github.com] Sent: Donnerstag, 19. Juli 2018 13:38 To: mxgxw/MFRC522-python MFRC522-python@noreply.github.com Cc: Liriel lassi@heisl.org; Comment comment@noreply.github.com Subject: Re: [mxgxw/MFRC522-python] Adapt Antenna Gain (#30)

Hello, just somehow got to your cool module so i thought i ask you. I bought some really cheap MFRC-522 reader/writers for my raspberry pi RFID project. Now i started testing the things, but was really disappointed by the distance of reading the passive tags (<1 cm) What i want to do is to achieve reading tags with a raspberry in a distance, lets say 0.5-1 meter and through clothes Do I need to get an antenna a differenet reader? Any good suggestion. How far does your reader read and trhorugh clothes too?? Thanks a lot

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/mxgxw/MFRC522-python/issues/30#issuecomment-406246512 , or mute the thread https://github.com/notifications/unsubscribe-auth/ABfiSY-xIMwXwnPnRioYq0QdmtdZHY9tks5uIG-ogaJpZM4JTYU2 . https://github.com/notifications/beacon/ABfiSR-hYrvcFhwzBpBGt8wIo-LfJ1uJks5uIG-ogaJpZM4JTYU2.gif

ThomasWoeg commented 5 years ago

Hi, yes that is exactly what I meant ! So, is it as simple as editing MFRC522.py in your example and adding this line ? def MFRC522_Init(self): GPIO.output(self.NRSTPD, 1) self.Write_MFRC522(self.RFCfgReg, (0x07<<4))

Doing this didn't actually change anything for me

himanipangasa commented 5 years ago

how to increase the read range of MFRC522 in raspberry pi 3? please help