My solenoid lock only work once and if I touch RFID card again it did not work anymore

Projects Programming
1

Hi, im new with arduino. My project is about RFID lock, component that I use is Arduino uno, 12V solenoid lock, and RFID-RC522. Here is my problem when doing this mini project, my RFID only work once and if I do it again the RFID did not detect my card and cannot unlock the solenoid lock. Please help me out from this problem, once I fix this problem I can complete this project.

2

Could be a programming error. Would you like us to look at your sketch to see if we can spot a problem?

In the meantime, in Preferences, set "Compiler warnings:" to "All" and verify your sketch. Carefully check every line the compiler warns you about.

1 Like
3

I bet the problem is either in the software or in the hardware/wiring.

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4

#include <SPI.h>
#include <MFRC522.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 RELAY 3 //relay pin
#define BUZZER 2 //buzzer pin
#define ACCESS_DELAY 2000
#define DENIED_DELAY 1000
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.

void setup()
{
Serial.begin(9600); // Initiate a serial communication
SPI.begin(); // Initiate SPI bus
mfrc522.PCD_Init(); // Initiate MFRC522
pinMode(LED_G, OUTPUT);
pinMode(LED_R, OUTPUT);
pinMode(RELAY, OUTPUT);
pinMode(BUZZER, OUTPUT);
noTone(BUZZER);
digitalWrite(RELAY, HIGH);
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) == "03 1B 53 1A") //change here the UID of the card/cards that you want to give access
{
Serial.println("Authorized access");
Serial.println();
delay(500);
digitalWrite(RELAY, LOW);
digitalWrite(LED_G, HIGH);
delay(ACCESS_DELAY);
digitalWrite(RELAY, HIGH);
digitalWrite(LED_G, LOW);
}

else {
Serial.println(" Access denied");
digitalWrite(LED_R, HIGH);
tone(BUZZER, 300);
delay(DENIED_DELAY);
digitalWrite(LED_R, LOW);
noTone(BUZZER);
}
}

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5

this is code that I use

6

looks like you repeatedly process your "content" message each iteration of loop().

shouldn't this processing only be done when a complete message has been received? and shouldn't the message buffer be cleared during the processing?

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7

If you use the same card twice in a row, is it reported as a 'new card'? In other words, do you get the message "Message : " each time you present the card or only the first time?

9

only the first time and than the card cannot detect anymore

10

What happens if you comment this part out?

/*
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent())
  {
    return;
  }
*/
11

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