Have to cut down a PN532 RFID Shield

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tomo21
 
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Joined: Sun Apr 14, 2013 10:35 pm

Have to cut down a PN532 RFID Shield

Post by tomo21 »

Hi all,

This is probably a bit unconventional, but I'm building a prototype of something with some pretty strict space requirements. I need to use RFID, but the Adafruit RFID shield is much too large. I tried cutting the loop antenna off and attaching it with wires, and simply wiring the 5 pins needed (I think?) for the i2c interface to my arduino. I managed to crush R3 on the shield when I was cutting it, but I replaced it with a 1.5ohm smd resistor. I chose 1.5 because I couldn't find a BoM online, and I measured R4 directly opposite it to be 1.5ohms.

When I try running the shield on my arduino, The power and busy lights come on, but I can't run any sketches. It fails at nfc.getFirmwareVersion() (the first nfc command I run in setup()) and tells me "Didn't find PN53x board."

My connections are A4, A5, 5V, Gnd, and D2. I think that's all I need.

Here are some photos of the cuts I made and of how I reattached the pcb antenna loop. It looks like I did a good job to me, but obviously something's gone wrong here.

EDIT
Deleted the posted pictures, they look awful in the forum interface. They're all herehttp://imgur.com/JZxTCcT,cfOiWjL,AmI1F8 ... Lb,MS9rk3m.
Last edited by tomo21 on Tue Mar 18, 2014 3:40 pm, edited 1 time in total.

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adafruit_support_bill
 
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Re: Have to cut down a PN532 RFID Shield

Post by adafruit_support_bill »

A lot that could have gone wrong there. Aside from the danger of cutting unintended traces, cutting PC boards tends to create static (that's why the dust sticks to everything). It is possible that static buildup from the cutting action could have damaged components. In any case, detaching the antenna like that is going to impair performance. The board designer may have some further insights into what failed.

tomo21
 
Posts: 17
Joined: Sun Apr 14, 2013 10:35 pm

Re: Have to cut down a PN532 RFID Shield

Post by tomo21 »

Would love to hear those insights. Any ideas on what I could do differently? Is there a better 'kit' to use perhaps?

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Franklin97355
 
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Re: Have to cut down a PN532 RFID Shield

Post by Franklin97355 »


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adafruit_support_bill
 
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Re: Have to cut down a PN532 RFID Shield

Post by adafruit_support_bill »

KTownsend addresses the difficulty of altering the integral antenna here. http://forums.adafruit.com/viewtopic.ph ... 6&p=169134
You are better off starting with a board designed to work with an external antenna such as the ones linked above.

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