arduino reads serial input from the pc

from_pc_to_arduino_serial.ino

int incomingByte = 0;   // for incoming serial data
const int ledPinRed =  2;      // the number of the LED pin
const int ledPinGreen =  3;      // the number of the LED pin
const int ledPinYellow = 4; 
const int ledPinBlue = 5;

void setup() {
    Serial.begin(9600);     // opens serial port, sets data rate to 9600 bps
    pinMode(ledPinRed, OUTPUT);
    pinMode(ledPinGreen, OUTPUT);
    pinMode(ledPinYellow, OUTPUT);
    pinMode(ledPinBlue, OUTPUT);
}

void loop() {

    // send data only when you receive data:
    if (Serial.available() > 0) {
        // read the incoming byte:
        incomingByte = Serial.read();

        // say what you got:
        Serial.print("I received: ");
        Serial.println(incomingByte, DEC);
        switch(incomingByte) {
          case 114: digitalWrite(ledPinRed, HIGH); delay(500); digitalWrite(ledPinRed, LOW); break;
          case 103: digitalWrite(ledPinGreen, HIGH); delay(500); digitalWrite(ledPinGreen, LOW); break;
          case 121: digitalWrite(ledPinYellow, HIGH); delay(500); digitalWrite(ledPinYellow, LOW); break;
          case 98: digitalWrite(ledPinBlue, HIGH); delay(500); digitalWrite(ledPinBlue, LOW); break;
          default: break;
        }

        delay(300);
    }
}