Unit 23: Access Codes

Code:


#include 

// Pin definitions
const int ledPin = 12;
const int buzzerPin = 11;

// Keypad settings
const byte ROWS = 4; // 4 rows
const byte COLS = 3; // 3 columns
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};

byte rowPins[ROWS] = {10, 9, 8, 7};  // Connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 5, 4};     // Connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Variables for code input
const String correctCode = "3107"; // Set the correct 4-digit code
String inputCode = ""; // Store the user’s input

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(ledPin, LOW); // Start with LED off
  digitalWrite(buzzerPin, LOW); // Start with buzzer off
}

void loop() {
  char key = keypad.getKey(); // Read the pressed key
  
  if (key) { // If a key is pressed
    inputCode += key; // Append the key to the input string
    
    if (inputCode.length() >= 4 && (key == '*' || key == '#')) { // After at least 4 digits and a final *, #
      if (inputCode.substring(0, 4) == correctCode) {
        digitalWrite(ledPin, HIGH); // Turn on the LED for correct code
        delay(2000); // Keep the LED on for 2 seconds
        digitalWrite(ledPin, LOW);
      } else {
        digitalWrite(buzzerPin, HIGH); // Sound the buzzer for wrong code
        delay(1000); // Buzzer sounds for 1 second
        digitalWrite(buzzerPin, LOW);
      }
      inputCode = ""; // Reset the input string for the next attempt
    }
  }
}

Code Two (Serial output):


    #include 

// Pin definitions
const int ledPin = 12;
const int buzzerPin = 11;

// Keypad settings
const byte ROWS = 4; // 4 rows
const byte COLS = 3; // 3 columns
char keys[ROWS][COLS] = {
  {'1', '2', '3'},
  {'4', '5', '6'},
  {'7', '8', '9'},
  {'*', '0', '#'}
};
byte rowPins[ROWS] = {10, 9, 8, 7};  // Connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 5, 4};      // Connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Variables for code input
const String correctCode = "2222"; // Set the correct 4-digit code
String inputCode = ""; // Store the user’s input

void setup() {
  Serial.begin(115200); // Start serial monitor at high speed
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(ledPin, LOW); // Start with LED off
  digitalWrite(buzzerPin, LOW); // Start with buzzer off
  
  Serial.println("System ready. Waiting for keypad input...");
}

void loop() {
  char key = keypad.getKey(); // Read the pressed key

  if (key) { // If a key is pressed
    Serial.print("Key Pressed: ");
    Serial.println(key);

    inputCode += key; // Append the key to the input string
    Serial.print("Current Input: ");
    Serial.println(inputCode);

    if (inputCode.length() >= 4 && (key == '*' || key == '#')) { // After 4 digits + final key
      Serial.print("Entered Code: ");
      Serial.println(inputCode.substring(0, 4));

      if (inputCode.substring(0, 4) == correctCode) {
        Serial.println("Correct Code! LED ON");
        digitalWrite(ledPin, HIGH); // Turn on the LED for correct code
        delay(2000); // Keep the LED on for 2 seconds
        digitalWrite(ledPin, LOW);
        Serial.println("LED OFF");
      } else {
        Serial.println("Wrong Code! Buzzer ON");
        digitalWrite(buzzerPin, HIGH); // Sound the buzzer for wrong code
        delay(1000); // Buzzer sounds for 1 second
        digitalWrite(buzzerPin, LOW);
        Serial.println("Buzzer OFF");
      }
      inputCode = ""; // Reset the input string for the next attempt
      Serial.println("Input reset. Waiting for new code...");
    }
  }
}

Unit 23: Access Codes

Code:

Notes: