Circuit Documentation

Summary

This circuit is designed to interface an Arduino UNO with an RFID-RC522 module, a 16x2 I2C LCD, and a Micro servo 9G. The Arduino UNO serves as the central microcontroller, managing the RFID reader, displaying information on the LCD, and controlling the servo motor.

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 reader module.
   • Pins: VCC (3.3V), RST, GND, IRQ, MISO, MOSI, SCK, SDA

3. 16x2 I2C LCD

   • Description: A 16x2 character LCD with I2C interface.
   • Pins: GND, VCC, SDA, SCL

4. Micro servo 9G

   • Description: A small servo motor used for precise control of angular position.
   • Pins: GND, +5V, PWM

Wiring Details

Arduino UNO

• 3.3V: Connected to VCC (3.3V) of RFID-RC522
• 5V: Connected to VCC of 16x2 I2C LCD and +5V of Micro servo 9G
• GND: Connected to GND of RFID-RC522, 16x2 I2C LCD, and Micro servo 9G
• A4: Connected to SDA of 16x2 I2C LCD
• A5: Connected to SCL of 16x2 I2C LCD
• 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
• D3: Connected to PWM of Micro servo 9G

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

16x2 I2C LCD

• VCC: Connected to 5V of Arduino UNO
• GND: Connected to GND of Arduino UNO
• SDA: Connected to A4 of Arduino UNO
• SCL: Connected to A5 of Arduino UNO

Micro servo 9G

• +5V: Connected to 5V of Arduino UNO
• GND: Connected to GND of Arduino UNO
• PWM: Connected to D3 of Arduino UNO

Code Documentation

RFID Tag Scan Code

/*RFID tag scan code
 * https://srituhobby.com
 */

#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN 9
#define SS_PIN  10
byte readCard[4];
byte a = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);
MFRC522 mfrc522(SS_PIN, RST_PIN);

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  while (!Serial);
  SPI.begin();
  mfrc522.PCD_Init();
  delay(4);
  mfrc522.PCD_DumpVersionToSerial();
  lcd.setCursor(2, 0);
  lcd.print("Put your card");
}

void loop() {
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return 0;
  }
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return 0;
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Scanned UID");
  a = 0;
  Serial.println(F("Scanned PICC's UID:"));
  for ( uint8_t i = 0; i < 4; i++) {  //
    readCard[i] = mfrc522.uid.uidByte[i];
    Serial.print(readCard[i], HEX);
    Serial.print(" ");
    lcd.setCursor(a, 1);
    lcd.print(readCard[i], HEX);
    lcd.print(" ");
    delay(500);
    a += 3;
  }
  Serial.println("");
  mfrc522.PICC_HaltA();
  return 1;
}

This code initializes the RFID reader and the LCD, and continuously checks for new RFID cards. When a card is detected, it reads the UID and displays it on the LCD and the serial monitor.