Circuit Documentation

Summary

This circuit is an RFID-based access control system using an Arduino UNO. It includes an RFID reader to scan tags, a servo motor to lock/unlock a mechanism, and two LEDs (red and green) to indicate access status. The system checks if the scanned RFID tag matches a predefined authorized tag.

Component List

1. LED: Two Pin (red)

   • Description: A red LED used to indicate access denial.
   • Pins: Cathode, Anode

2. Arduino UNO

   • Description: The main microcontroller used to control the circuit.
   • 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

3. Servo

   • Description: A servo motor used to lock/unlock the mechanism.
   • Pins: GND, VCC, Pulse

4. Resistor (200 Ohms)

   • Description: A resistor used to limit current.
   • Pins: Pin1, Pin2
   • Properties: Resistance: 200 Ohms

5. LED: Two Pin (green)

   • Description: A green LED used to indicate access granted.
   • Pins: Cathode, Anode

6. RFID-RC522

   • Description: An RFID reader module used to scan RFID tags.
   • Pins: VCC (3.3V), RST, GND, IRQ, MISO, MOSI, SCK, SDA

7. GND

   • Description: Ground connection.
   • Pins: GND

Wiring Details

LED: Two Pin (red)

• Cathode connected to GND
• Anode connected to Pin1 of a 200 Ohm resistor

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 and GND of Servo
• D13 connected to SCK of RFID-RC522
• D12 connected to MISO of RFID-RC522
• D11 connected to MOSI of RFID-RC522
• D10 connected to SDA of RFID-RC522
• D9 connected to RST of RFID-RC522
• D8 connected to Pin2 of a 200 Ohm resistor
• D7 connected to Pin2 of another 200 Ohm resistor
• D6 connected to Pulse of Servo

Servo

• VCC connected to 5V of Arduino UNO
• GND connected to GND of Arduino UNO
• Pulse connected to D6 of Arduino UNO

Resistor (200 Ohms)

• Pin1 connected to Anode of red LED
• Pin2 connected to D8 of Arduino UNO

LED: Two Pin (green)

• Anode connected to Pin1 of another 200 Ohm resistor
• Cathode connected to GND

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
• SCK connected to D13 of Arduino UNO
• MISO connected to D12 of Arduino UNO
• MOSI connected to D11 of Arduino UNO
• SDA connected to D10 of Arduino UNO

GND

• GND connected to Cathode of green LED

Code Documentation

Arduino UNO Code

/*
 * This Arduino sketch controls an RFID-based access system.
 * It uses an RFID reader to scan tags and a servo motor to
 * lock/unlock a mechanism. Green and red LEDs indicate access
 * status. The system checks if the scanned RFID tag matches
 * a predefined authorized tag.
 */

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

#define RST_PIN 9
#define SS_PIN 10

MFRC522 rfid(SS_PIN, RST_PIN);
Servo serrure;

String tagAutorise = "AB CD EF 12"; // Replace with your tag UID

void setup() {
  Serial.begin(9600);
  SPI.begin();
  rfid.PCD_Init();
  serrure.attach(6); // Servo pin
  serrure.write(0);  // Lock

  pinMode(7, OUTPUT); // Green LED
  pinMode(8, OUTPUT); // Red LED
  digitalWrite(7, LOW);
  digitalWrite(8, LOW);

  Serial.println("Ready to scan a tag.");
}

void loop() {
  if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial()) {
    return;
  }

  String uid = "";
  for (byte i = 0; i < rfid.uid.size; i++) {
    uid += String(rfid.uid.uidByte[i], HEX);
    if (i < rfid.uid.size - 1) uid += " ";
  }
  uid.toUpperCase();
  Serial.println("UID tag: " + uid);

  if (uid == tagAutorise) {
    digitalWrite(7, HIGH); // Green LED on
    digitalWrite(8, LOW);  // Red LED off
    Serial.println("Access granted!");
    serrure.write(90); // Unlock
    delay(5000);       // Wait before locking
    serrure.write(0);  // Lock
  } else {
    digitalWrite(7, LOW);  // Green LED off
    digitalWrite(8, HIGH); // Red LED on
    Serial.println("Access denied!");
    delay(2000);
  }

  rfid.PICC_HaltA();
}

GND 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 a summary, component list, wiring details, and the code used in the Arduino UNO.