Circuit Documentation

Summary

This circuit involves an Arduino UNO microcontroller interfaced with an RFID-RC522 module, two LEDs (red and green), and a servo motor. The circuit is designed to read RFID cards. When a card is recognized, the green LED lights up, and the servo motor rotates 180 degrees. If the card reading fails, the red LED lights up.

Component List

1. Arduino UNO

   • Description: A microcontroller board based on the ATmega328P.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

2. RFID-RC522

   • Description: A low-cost RFID module that uses the MFRC522 IC.
   • Pins: VCC (3.3V), RST, GND, IRQ, MISO, MOSI, SCK, SDA

3. LED: Two Pin (red)

   • Description: A standard red LED.
   • Pins: cathode, anode

4. LED: Two Pin (green)

   • Description: A standard green LED.
   • Pins: cathode, anode

5. Servo

   • Description: A standard servo motor.
   • Pins: GND, VCC, PWM

Wiring Details

Arduino UNO

• 3.3V: Connected to VCC (3.3V) of RFID-RC522
• 5V: Connected to VCC of Servo
• GND: Connected to GND of RFID-RC522, GND of Servo, cathode of red LED, and cathode of green LED
• D9: Connected to RST of RFID-RC522
• D8: Connected to anode of red LED
• D7: Connected to anode of green LED
• D6: Connected to PWM of Servo

RFID-RC522

• VCC (3.3V): Connected to 3.3V of Arduino UNO
• RST: Connected to D9 of Arduino UNO
• GND: Connected to GND of Arduino UNO

LED: Two Pin (red)

• cathode: Connected to GND of Arduino UNO
• anode: Connected to D8 of Arduino UNO

LED: Two Pin (green)

• cathode: Connected to GND of Arduino UNO
• anode: Connected to D7 of Arduino UNO

Servo

• GND: Connected to GND of Arduino UNO
• VCC: Connected to 5V of Arduino UNO
• PWM: Connected to D6 of Arduino UNO

Code Documentation

Arduino UNO Code

/*
 * This Arduino sketch initializes the RFID-RC522 module and turns on a green
 * LED when a card is recognized. If the card reading fails, a red LED is
 * turned on. Additionally, when the green LED is turned on, a servo motor
 * rotates 180 degrees.
 */

#include <SPI.h>
#include <MFRC522.h>
#include <Servo.h>

#define RST_PIN 9
#define SS_PIN 10
#define GREEN_LED_PIN 7
#define RED_LED_PIN 8
#define SERVO_PIN 6

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance
Servo myServo; // Create Servo instance

void setup() {
  Serial.begin(9600); // Initialize serial communications
  SPI.begin(); // Init SPI bus
  mfrc522.PCD_Init(); // Init MFRC522
  pinMode(GREEN_LED_PIN, OUTPUT); // Set green LED pin as output
  pinMode(RED_LED_PIN, OUTPUT); // Set red LED pin as output
  digitalWrite(GREEN_LED_PIN, LOW); // Turn off green LED initially
  digitalWrite(RED_LED_PIN, LOW); // Turn off red LED initially
  myServo.attach(SERVO_PIN); // Attach servo to pin
  myServo.write(0); // Initialize servo position to 0 degrees
  Serial.println("Place your card to the reader...");
}

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

  // Select one of the cards
  if (!mfrc522.PICC_ReadCardSerial()) {
    Serial.println("Card read failed!");
    digitalWrite(RED_LED_PIN, HIGH);
    delay(1000); // Keep red LED on for 1 second
    digitalWrite(RED_LED_PIN, LOW);
    return;
  }

  // If a card is detected, turn on the green LED and rotate servo
  Serial.println("Card detected!");
  digitalWrite(GREEN_LED_PIN, HIGH);
  myServo.write(180); // Rotate servo to 180 degrees
  delay(1000); // Keep green LED on for 1 second
  digitalWrite(GREEN_LED_PIN, LOW);
  myServo.write(0); // Reset servo to 0 degrees
}

RFID-RC522 Code

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

This documentation provides a comprehensive overview of the circuit, including the components used, their wiring details, and the code running on the microcontroller.