โค้ดวงจรคีย์แพดควบคุม LED.

#include <Keypad.h>

const byte ROWS = 4; // Four rows

const byte COLS = 4; // Four columns

// Define the symbols on the buttons of the keypad

char hexaKeys[ROWS][COLS] = {

  {'1','4','7','*'},

  {'2','5','8','0'},

  {'3','6','9','#'},

  {'A','B','C','D'}

};

byte colPins[COLS] = {5, 4, 3, 2}; // Connect to the column pinouts of the keypad

byte rowPins[ROWS] = {9, 8, 7, 6}; // Connect to the row pinouts of the keypad

// Initialize an instance of class Keypad

Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);

const int ledPin = 12; // LED connected to pin 12

String inputCode = ""; // To store the input code

String targetCode = "14157"; // The correct code

void setup() {

  pinMode(ledPin, OUTPUT); // Set the LED pin as an output

  digitalWrite(ledPin, LOW); // Initially turn off the LED

  Serial.begin(115200);

}

void loop() {

  char customKey = customKeypad.getKey();

  if (customKey) {

    Serial.println(customKey); // Print the pressed key to the Serial Monitor

    inputCode += customKey; // Append the pressed key to the input code

    // Check if the input code matches the target code

    if (inputCode.length() == targetCode.length()) {

      if (inputCode == targetCode) {

        digitalWrite(ledPin, HIGH); // Turn on the LED

        delay(5000); // Keep the LED on for 5 seconds

        digitalWrite(ledPin, LOW); // Turn off the LED after 5 seconds

      }

      inputCode = ""; // Reset the input code after checking

    }

  }

}