so i have an mfrc522 rfid scanner, i connected it to an arduino mega, i checked the connections and they are fine. when ever i use code that is not from the examples it doesn't work, the red led is on, the power is connected to 3.3 volts on the arduino and there are no errors. it just won't detect the card. it works fin on examples though.
Hi,
Post the sketch that works, the sketch that doesn't work and the wiring diagram of your project.
When posting the sketches, place them between tags </>
RV mineirin
Your post was MOVED to a more suitable location.
Could you also review How to get the best out of this forum as it will help you find your way around.
here is the working code
/*
* Initial Author: ryand1011 (https://github.com/ryand1011)
*
* Reads data written by a program such as "rfid_write_personal_data.ino"
*
* See: https://github.com/miguelbalboa/rfid/tree/master/examples/rfid_write_personal_data
*
* Uses MIFARE RFID card using RFID-RC522 reader
* Uses MFRC522 - Library
* -----------------------------------------------------------------------------------------
* MFRC522 Arduino Arduino Arduino Arduino Arduino
* Reader/PCD Uno/101 Mega Nano v3 Leonardo/Micro Pro Micro
* Signal Pin Pin Pin Pin Pin Pin
* -----------------------------------------------------------------------------------------
* RST/Reset RST 9 5 D9 RESET/ICSP-5 RST
* SPI SS SDA(SS) 10 53 D10 10 10
* SPI MOSI MOSI 11 / ICSP-4 51 D11 ICSP-4 16
* SPI MISO MISO 12 / ICSP-1 50 D12 ICSP-1 14
* SPI SCK SCK 13 / ICSP-3 52 D13 ICSP-3 15
*/
#include <SPI.h>
#include <MFRC522.h>
#define RST_PIN 9 // Configurable, see typical pin layout above
#define SS_PIN 10 // Configurable, see typical pin layout above
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance
//*****************************************************************************************//
void setup() {
Serial.begin(9600); // Initialize serial communications with the PC
SPI.begin(); // Init SPI bus
mfrc522.PCD_Init(); // Init MFRC522 card
Serial.println(F("Read personal data on a MIFARE PICC:")); //shows in serial that it is ready to read
}
//*****************************************************************************************//
void loop() {
// Prepare key - all keys are set to FFFFFFFFFFFFh at chip delivery from the factory.
MFRC522::MIFARE_Key key;
for (byte i = 0; i < 6; i++) key.keyByte[i] = 0xFF;
//some variables we need
byte block;
byte len;
MFRC522::StatusCode status;
//-------------------------------------------
// Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.
if ( ! mfrc522.PICC_IsNewCardPresent()) {
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial()) {
return;
}
Serial.println(F("**Card Detected:**"));
//-------------------------------------------
mfrc522.PICC_DumpDetailsToSerial(&(mfrc522.uid)); //dump some details about the card
//mfrc522.PICC_DumpToSerial(&(mfrc522.uid)); //uncomment this to see all blocks in hex
//-------------------------------------------
Serial.print(F("Name: "));
byte buffer1[18];
block = 4;
len = 18;
//------------------------------------------- GET FIRST NAME
status = mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, 4, &key, &(mfrc522.uid)); //line 834 of MFRC522.cpp file
if (status != MFRC522::STATUS_OK) {
Serial.print(F("Authentication failed: "));
Serial.println(mfrc522.GetStatusCodeName(status));
return;
}
status = mfrc522.MIFARE_Read(block, buffer1, &len);
if (status != MFRC522::STATUS_OK) {
Serial.print(F("Reading failed: "));
Serial.println(mfrc522.GetStatusCodeName(status));
return;
}
//PRINT FIRST NAME
for (uint8_t i = 0; i < 16; i++)
{
if (buffer1[i] != 32)
{
Serial.write(buffer1[i]);
}
}
Serial.print(" ");
//---------------------------------------- GET LAST NAME
byte buffer2[18];
block = 1;
status = mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, 1, &key, &(mfrc522.uid)); //line 834
if (status != MFRC522::STATUS_OK) {
Serial.print(F("Authentication failed: "));
Serial.println(mfrc522.GetStatusCodeName(status));
return;
}
status = mfrc522.MIFARE_Read(block, buffer2, &len);
if (status != MFRC522::STATUS_OK) {
Serial.print(F("Reading failed: "));
Serial.println(mfrc522.GetStatusCodeName(status));
return;
}
//PRINT LAST NAME
for (uint8_t i = 0; i < 16; i++) {
Serial.write(buffer2[i] );
}
//----------------------------------------
Serial.println(F("\n**End Reading**\n"));
delay(1000); //change value if you want to read cards faster
mfrc522.PICC_HaltA();
mfrc522.PCD_StopCrypto1();
}
//*****************************************************************************************//
and here is the non working code
#include <SPI.h>
#include <MFRC522.h>
#include <Servo.h>
#define SS_PIN 10
#define RST_PIN 9
#define LED_G 5 //define green LED pin
#define LED_R 4 //define red LED
#define BUZZER 2 //buzzer pin
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
Servo myServo; //define servo name
void setup()
{
Serial.begin(9600); // Initiate a serial communication
SPI.begin(); // Initiate SPI bus
mfrc522.PCD_Init(); // Initiate MFRC522
myServo.attach(3); //servo pin
myServo.write(0); //servo start position
pinMode(LED_G, OUTPUT);
pinMode(LED_R, OUTPUT);
pinMode(BUZZER, OUTPUT);
noTone(BUZZER);
Serial.println("Put your card to the reader...");
Serial.println();
}
void loop()
{
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent())
{
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial())
{
return;
}
//Show UID on serial monitor
Serial.print("UID tag :");
String content= "";
byte letter;
for (byte i = 0; i < mfrc522.uid.size; i++)
{
Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
Serial.print(mfrc522.uid.uidByte[i], HEX);
content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
content.concat(String(mfrc522.uid.uidByte[i], HEX));
}
Serial.println();
Serial.print("Message : ");
content.toUpperCase();
if (content.substring(1) == "8D 20 06 85") //change here the UID of the card/cards that you want to give access
{
Serial.println("Authorized access");
Serial.println();
delay(500);
digitalWrite(LED_G, HIGH);
tone(BUZZER, 500);
delay(300);
noTone(BUZZER);
myServo.write(180);
delay(5000);
myServo.write(0);
digitalWrite(LED_G, LOW);
}
else {
Serial.println(" Access denied");
digitalWrite(LED_R, HIGH);
tone(BUZZER, 300);
delay(1000);
digitalWrite(LED_R, LOW);
noTone(BUZZER);
}
}
how about adding serial-output to see what is going on?
global defined variables of type String eat up all memory over time and will cause hard to find crashes
You should use something like PString or SafeString
Another approach start new from the working code adding only a few lines of code re-compile and test
best regards Stefan
should i mention i don't really understand C++ i just command c command v into the IDE. i am a noob that just bought an elegoo kit
Most newcomers add a lot of code before they start to test.
You should do it exactly opposite. Add just a few lines of code and test again
best regards Stefan
thanks for the help!
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