Hello, I'm new here!!! I bought two Arduinos to test my RFID RC522. I installed the MFRC522 library, and every time I start the program with my two arduinos, it tells me this error: WARNING: Communication failure, is the MFRC522 properly connected? Scan PICC to see UID, SAK, type and data blocks.... I tried attaching all the cables directly to my arduino and also tried with a breadboard, but every time it said that. I've watched a lot of videos, but nothing works. Can anyone help me please???
Could be a program code, wiring or power supply error.
For help, have a look at the "How to get the best out of this forum" post and follow the instructions.
try one at a time
Hi, thank you for your response. Can we talk together??? I would like to send you a photo of my cable and code. I'm new to Arduino, and I've had this problem for 1 week!
You mean, one arduino at a time?
Are you saying one independent Arduino interferes with the other? How?
and I think because the program won't know which Arduino to upload
Do you understand the word "independent?" Stick to broken servos.
Forum members expect you to post those details. That way you can expect help from more people.
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You might want to look at this How to get the best out of this forum before you proceed any further.
We only know what you tell us, and without knowing what you have, we don't stand a chance.
The link will also tell you how to post code here. As a beginner you can post one picture, so make it a good one of your schematic.
Note the way to connect the 3V3 RC522 to a 5V Arduino is something the whole internet gets wrong. Signals from the 5V Arduino need cutting down to 3V3 with potential dividers like this diagram shows.
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