Arduino

int buzzer = 8;   // Assign buzzer to pin 8
int note = 1000;  // Set the pitch for the buzzer tone
#define LED_PIN 12

int timeUnit = 100;  // This variable will be used to measure dots, dashes, breaks, and pauses
char input;          // Variable to save the input to



void setup() {
  Serial.begin(9600);  //for the connect with the boared
  pinMode(LED_PIN, OUTPUT);
}

void loop() {

  digitalWrite(LED_PIN, LOW);
  if (Serial.available()) {
    input = Serial.read();                       //read the input
    if (input == 'a' || input == 'A') { lA(); }  //if the input is a or A go to function lA
    if (input == 'b' || input == 'B') { lB(); }  //same but with b letter
    if (input == 'c' || input == 'C') { lC(); }
    if (input == 'd' || input == 'D') { lD(); }
    if (input == 'e' || input == 'E') { lE(); }
    if (input == 'f' || input == 'F') { lF(); }
    if (input == 'g' || input == 'G') { lG(); }
    if (input == 'h' || input == 'H') { lH(); }
    if (input == 'i' || input == 'I') { lI(); }
    if (input == 'j' || input == 'J') { lJ(); }
    if (input == 'k' || input == 'K') { lK(); }
    if (input == 'l' || input == 'L') { lL(); }
    if (input == 'm' || input == 'M') { lM(); }
    if (input == 'n' || input == 'N') { lN(); }
    if (input == 'o' || input == 'O') { lO(); }
    if (input == 'p' || input == 'P') { lP(); }
    if (input == 'q' || input == 'Q') { lQ(); }
    if (input == 'r' || input == 'R') { lR(); }
    if (input == 's' || input == 'S') { lS(); }
    if (input == 't' || input == 'T') { lT(); }
    if (input == 'u' || input == 'U') { lU(); }
    if (input == 'v' || input == 'V') { lV(); }
    if (input == 'w' || input == 'W') { lW(); }
    if (input == 'x' || input == 'X') { lX(); }
    if (input == 'y' || input == 'Y') { lY(); }
    if (input == 'z' || input == 'Z') { lZ(); }
    if (input == ' ') { wordPause(); }
    Serial.println(input);
  }
}
//Letter functions
void lA() {
  dot();
  dash();
  letterPause();
}  //letter A in morse code!
void lB() {
  dash();
  dot();
  dot();
  dot();
  letterPause();
}  //same for B
void lC() {
  dash();
  dot();
  dash();
  dot();
  letterPause();
}
void lD() {
  dash();
  dot();
  dot();
  letterPause();
}
void lE() {
  dot();
  letterPause();
}
void lF() {
  dot();
  dot();
  dash();
  dot();
  letterPause();
}
void lG() {
  dash();
  dash();
  dot();
  letterPause();
}
void lH() {
  dot();
  dot();
  dot();
  dot();
  letterPause();
}
void lI() {
  dot();
  dot();
  letterPause();
}
void lJ() {
  dot();
  dash();
  dash();
  dash();
  letterPause();
}
void lK() {
  dash();
  dot();
  dash();
  letterPause();
}
void lL() {
  dot();
  dash();
  dot();
  dot();
  letterPause();
}
void lM() {
  dash();
  dash();
  letterPause();
}
void lN() {
  dash();
  dot();
  letterPause();
}
void lO() {
  dash();
  dash();
  dash();
  letterPause();
}
void lP() {
  dot();
  dash();
  dash();
  dot();
  letterPause();
}
void lQ() {
  dash();
  dash();
  dot();
  dash();
  letterPause();
}
void lR() {
  dot();
  dash();
  dot();
  letterPause();
}
void lS() {
  dot();
  dot();
  dot();
  letterPause();
}
void lT() {
  dash();
  letterPause();
}
void lU() {
  dot();
  dot();
  dash();
  letterPause();
}
void lV() {
  dot();
  dot();
  dot();
  dash();
  letterPause();
}
void lW() {
  dot();
  dash();
  dash();
  letterPause();
}
void lX() {
  dash();
  dot();
  dot();
  dash();
  letterPause();
}
void lY() {
  dash();
  dot();
  dash();
  dash();
  letterPause();
}
void lZ() {
  dash();
  dash();
  dot();
  dot();
  letterPause();
}

void dot()  //Emit sound for 100 milliseconds
{
  tone(buzzer, note, timeUnit);
  digitalWrite(LED_PIN, HIGH);
  delay(timeUnit * 2);
  digitalWrite(LED_PIN, LOW);  // 根据声音长短，灯闪动长短
  delay(100);
}

void dash()  //Emit sound for 300 milliseconds
{
  tone(buzzer, note, timeUnit * 3);
  digitalWrite(LED_PIN, HIGH);
  delay(timeUnit * 4);
  digitalWrite(LED_PIN, LOW);
  delay(100);
}

void letterPause()  //Delay between letters for 300 milliseconds
{
  delay(timeUnit * 3);
}

void wordPause() {
  delay(timeUnit * 7);
}