Circuit Documentation

Summary

This circuit is designed to automate a petrol pump system using an Arduino Nano microcontroller. The system includes an RFID reader for user authentication, a keypad for password and cost input, an LCD screen for user interface, a relay to control a water pump (simulating the petrol pump), and a buzzer for alerts. The system ensures secure transactions by verifying the user's RFID card and password before dispensing fuel.

Component List

1. Arduino Nano

   • Description: A small, complete, and breadboard-friendly board based on the ATmega328P.
   • Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

2. LCD screen 16x2 I2C

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

3. 5V Mini Water Pump

   • Description: A small water pump operating at 5V.
   • Pins: Positive pin, Negative pin

4. RFID-RC522

   • Description: An RFID reader module operating at 3.3V.
   • Pins: VCC (3.3V), RST, GND, IRQ, MISO, MOSI, SCK, SDA

5. Piezo Buzzer

   • Description: A small piezoelectric buzzer for sound alerts.
   • Pins: Pin 1, Pin 2

6. 1 Channel Relay 5V

   • Description: A relay module to control high voltage devices with a 5V signal.
   • Pins: VCC, GND, IN, NC, COM, NO

7. 4X4 Membrane Matrix Keypad

   • Description: A 4x4 matrix keypad for user input.
   • Pins: R1, R2, R3, R4, C1, C2, C3, C4

8. 9V Battery

   • Description: A standard 9V battery for power supply.
   • Pins: Positive (+), Negative (-)

Wiring Details

Arduino Nano

• D6: Connected to R1 of the 4X4 Membrane Matrix Keypad
• D5: Connected to R2 of the 4X4 Membrane Matrix Keypad
• D4: Connected to R3 of the 4X4 Membrane Matrix Keypad
• D3: Connected to R4 of the 4X4 Membrane Matrix Keypad
• D2: Connected to C1 of the 4X4 Membrane Matrix Keypad
• A1: Connected to C2 of the 4X4 Membrane Matrix Keypad
• A2: Connected to C3 of the 4X4 Membrane Matrix Keypad
• A3: Connected to C4 of the 4X4 Membrane Matrix Keypad
• A5: Connected to SCL of the LCD screen 16x2 I2C
• A4: Connected to SDA of the LCD screen 16x2 I2C
• 5V: Connected to VCC of the LCD screen 16x2 I2C and VCC of the 1 Channel Relay 5V
• GND: Connected to GND of the LCD screen 16x2 I2C, GND of the 1 Channel Relay 5V, GND of the RFID-RC522, and Pin 2 of the Piezo Buzzer
• 3V3: Connected to VCC (3.3V) of the RFID-RC522
• D9: Connected to RST of the RFID-RC522
• D12/MISO: Connected to MISO of the RFID-RC522
• D11/MOSI: Connected to MOSI of the RFID-RC522
• D13/SCK: Connected to SCK of the RFID-RC522
• D10: Connected to SDA of the RFID-RC522
• D8: Connected to IN of the 1 Channel Relay 5V
• D7: Connected to Pin 1 of the Piezo Buzzer

LCD screen 16x2 I2C

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

5V Mini Water Pump

• Positive pin: Connected to NC of the 1 Channel Relay 5V
• Negative pin: Connected to Negative (-) of the 9V Battery

RFID-RC522

• VCC (3.3V): Connected to 3V3 of the Arduino Nano
• RST: Connected to D9 of the Arduino Nano
• GND: Connected to GND of the Arduino Nano
• MISO: Connected to D12/MISO of the Arduino Nano
• MOSI: Connected to D11/MOSI of the Arduino Nano
• SCK: Connected to D13/SCK of the Arduino Nano
• SDA: Connected to D10 of the Arduino Nano

Piezo Buzzer

• Pin 1: Connected to D7 of the Arduino Nano
• Pin 2: Connected to GND of the Arduino Nano

1 Channel Relay 5V

• VCC: Connected to 5V of the Arduino Nano
• GND: Connected to GND of the Arduino Nano
• IN: Connected to D8 of the Arduino Nano
• NC: Connected to Positive pin of the 5V Mini Water Pump
• COM: Connected to Positive (+) of the 9V Battery

4X4 Membrane Matrix Keypad

• R1: Connected to D6 of the Arduino Nano
• R2: Connected to D5 of the Arduino Nano
• R3: Connected to D4 of the Arduino Nano
• R4: Connected to D3 of the Arduino Nano
• C1: Connected to D2 of the Arduino Nano
• C2: Connected to A1 of the Arduino Nano
• C3: Connected to A2 of the Arduino Nano
• C4: Connected to A3 of the Arduino Nano

9V Battery

• Positive (+): Connected to COM of the 1 Channel Relay 5V
• Negative (-): Connected to Negative pin of the 5V Mini Water Pump

Code Documentation

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

// Pin configuration for Arduino Nano
#define RST_PIN 9    // Reset pin for MFRC522
#define SS_PIN 10    // Slave select pin for MFRC522
#define RELAY_PIN 8  // Relay to control pump
#define BUZZER_PIN 7 // Buzzer for alerts

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance
LiquidCrystal_I2C lcd(0x27, 16, 2); // Create I2C LCD instance (I2C address: 0x27)

// Keypad configuration
const byte ROWS = 4; // Rows of the keypad
const byte COLS = 4; // Columns of the keypad
char keys[ROWS][COLS] = {
    {'1', '2', '3', 'A'},
    {'4', '5', '6', 'B'},
    {'7', '8', '9', 'C'},
    {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {6, 5, 4, 3}; // Connect to row pins of the keypad
byte colPins[COLS] = {2, A1, A2, A3}; // Connect to column pins of the keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// User data (Simulated RFID card data, password, and balance)
String validRFID = "d3:1e:34:27"; 
String validPassword = "