I built a circuit with a MEGA2560 that contains an RFID reader and relay. When the RFID reader sees a specific fob, it needs to switch the relay to closed.
That is, the relay is in an open state all the time except when the fob touches the reader.
The relay controls 12v going to a magnet that I'm going to use to lock a door.
Once in a while, the whole circuit hangs. The RFID reader stops responding. It's not a code issue. I suspect an electric issue.
Appreciate your help.
Video explanation : https://photos.app.goo.gl/iMNhRxiXGNPbqpPbA
/*
PINOUT:
RC522 MODULE Uno/Nano MEGA
SDA D10 D9
SCK D13 D52
MOSI D11 D51
MISO D12 D50
IRQ N/A N/A
GND GND GND
RST D9 D8
3.3V 3.3V 3.3V
*/
/* Include the standard Arduino SPI library */
#include <SPI.h>
/* Include the RFID library */
#include <RFID.h>
#include "pitches.h"
/* Define the DIO used for the SDA (SS) and RST (reset) pins. */
#define SDA_DIO 9
#define RESET_DIO 8
/* card IDs */
#define ETHAN_PHONE 86924247144
#define BLUE_FOB 601852375595
#define WHITE_CARD 2112021385150
/* Create an instance of the RFID library */
RFID RC522(SDA_DIO, RESET_DIO);
#define GREEN_LED 3
#define RED_LED 2
#define MAGNET 5
#define BUZZER 10
void setup()
{
Serial.begin(9600);
/* Enable the SPI interface */
SPI.begin();
/* Initialise the RFID reader */
RC522.init();
Serial.println("Hello!");
}
void loop()
{
/* Has a card been detected? */
delay(1000);
if (RC522.isCard())
{
/* If so then get its serial number */
RC522.readCardSerial();
Serial.println("Card detected:");
char buf[15];
sprintf(buf, "%d%d%d%d%d", RC522.serNum[0], RC522.serNum[1], RC522.serNum[2], RC522.serNum[3], RC522.serNum[4]);
Serial.println(buf);
Serial.println();
if (strcmp(buf, "601852375595") == 0) {
Serial.println("It's the blue fob!");
digitalWrite(GREEN_LED, HIGH);
digitalWrite(RED_LED, LOW);
analogWrite(MAGNET, 0 );
tone(BUZZER, NOTE_FS3, 1000);
delay(5000);
}
} else {
digitalWrite(GREEN_LED, LOW);
digitalWrite(RED_LED, HIGH);
analogWrite(MAGNET, 255);
}
}
