ondryaso / pi-rc522

Raspberry Pi Python library for SPI RFID RC522 module
MIT License
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getting E1 or E2 error #60

Open zionnoizy opened 5 years ago

zionnoizy commented 5 years ago

whenever I screen the card, it only prints E1 or E2, but I have no idea where E1 or E2 comes from? I follow the instruction in here:

http://www.penguintutor.com/news/raspberrypi/rfid-rc522

how to avoid the errors to print "Detected" successfully?

#!/usr/bin/python3

import sys
sys.path.insert(0, "/home/pi/pi-rc522/ChipReader")
from pirc522 import RFID
import signal
import time
import RPi.GPIO as GPIO
from mfrc522 import SimpleMFRC522

reader = RFID()
util = reader.util()
util.debug = False

print("reader= ", reader)
print("util= ", util)

while True:
    (error, data) = reader.request()
    print("reader.request()= ", reader.request()) 
    if not error:
        print("\nDetected")
        (error, uid) = reader.anticoll()
        if not error:
            print ("str(uid[0]) " +str(uid[0])+ ", "+str(uid[1])+", "+str(uid[2])+", "+str(uid[3]))
            time.sleep(1)

print E1/E2 cannot print Detected, all connection and installation should work.

nanbuwks commented 3 years ago

In pirc522/rfid.py, lines 191 and 221, we have the corresponding code.

print("E1")

so we have print("E1", file=sys.stderr) should be

LateAtGit commented 3 years ago

I have a similar problem, sometimes I read a tag and I get "E2" error, I tried to read the code but I have no Idea what the reason is.

Can someone help me please?

Thank you

nanbuwks commented 3 years ago

There are several ways to solve this, but if you do not want to rewrite lines 191 and 221 of the library, you can use You can use redirect_stdout. In Python 3.5 or later, this can be achieved as follows:


import io
import os
from contextlib import redirect_stdout

from pirc522 import RFID
rdr = RFID()

f = io.StringIO()

while True:
  rdr.wait_for_tag()
  with redirect_stdout(f):
      (error, tag_type) = rdr.request()
  # print(f.getvalue())  # if need print "E1" or "E2"
  if not error:
    print("Tag detected")
    with redirect_stdout(f):
      (error, uid) = rdr.anticoll()
    # print(f.getvalue())  # if need print "E1" or "E2"
    if not error:
       print("UID: " + str(uid))

# Calls GPIO cleanup
rdr.cleanup()

If you do not need to capture E1 and E2, you can use


f = open(os.devnull,'w')

instead of


f = io.StringIO()

.

LateAtGit commented 3 years ago

Hi nanbuwks, thank you for the answer, but I'm more interested in knowing why the error occours (and maybe solve or manage it) than suppress the message.

nanbuwks commented 3 years ago

Since we are using radio waves, there will always be errors at the boundary of the reaction.

However, aren't you plagued by a large number of errors?

IMG_20200304_153805.jpg

When I used such a module as it is, it was quite unstable as shown below.


Detected
Card read UID: 242,195,43,51
Selecting UID [242, 195, 43, 51, 41].
Changing used auth key to [255, 255, 255, 255, 255, 255] using method B
Calling card_auth on UID [242, 195, 43, 51, 41].
E2
Error on S1.0B0
Not calling card_auth - already authed
S1.0B0: [2] B
Calling card_auth on UID [242, 195, 43, 51, 41].
Error on S1.0B2
Changing used auth key to [255, 255, 255, 255, 255, 255] using method A
Calling card_auth on UID [242, 195, 43, 51, 41].
Not calling card_auth - already authed
Not calling card_auth - already authed
S2.0B1: []
Calling card_auth on UID [242, 195, 43, 51, 41].
Error on S0.0B0
Calling card_auth on UID [242, 195, 43, 51, 41] Error on S0.0B0
Error on S0.0B1
Calling card_auth on UID [242, 195, 43, 51, 41] Error on S0.0B1
Error on S0.0B2
.
.
.
Calling card_auth on UID [242, 195, 43, 51, 41]
Error on S15.0B2
Calling card_auth on UID [242, 195, 43, 51, 41] Error on S15.0B2
Error on S15.0B3
Changing auth key and method to None

To solve this problem, adding a capacitor was effective.

IMG_20200312_130200.jpg

In the picture, a 47μF capacitor has been installed to improve the 3.3V power supply.