Open zionnoizy opened 5 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
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
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()
.
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.
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?
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.
In the picture, a 47μF capacitor has been installed to improve the 3.3V power supply.
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?
print E1/E2 cannot print Detected, all connection and installation should work.