const int buttonPin = 0;     // the number of the pushbutton pin
const int ledPin1 =  1;      // the number of the LED pin
const int ledPin2 =  2;      // the number of the LED pin
const int ledPin3 =  3;      // the number of the LED pin
int incomingByte = 0;

// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status
int buttonCount =  0;

int delay_interval = 0;

void setup() {
  Serial.begin(115200);
  // initialize the LED pin as an output:
  pinMode(ledPin1, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(ledPin2, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(ledPin3, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {

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

    Serial.print("I received: ");
    Serial.println((char)incomingByte, DEC);
  }

  if ( incomingByte == '0') {  //do nothing

  } else if ( incomingByte == '1') {
    digitalWrite(ledPin1, HIGH); // turn on LED1
  } else if (incomingByte == '2') {
    digitalWrite(ledPin2, HIGH);
  } else if (incomingByte == '3') {
    digitalWrite(ledPin3, HIGH);
  } else if ( incomingByte == '4') {
    digitalWrite(ledPin1, LOW);
  } else if (incomingByte == '5') {
    digitalWrite(ledPin2, LOW);
  } else if (incomingByte == '6') {
    digitalWrite(ledPin3, LOW);

  } else if (incomingByte == '9') {
    digitalWrite(ledPin1, LOW);
    digitalWrite(ledPin2, LOW);
    digitalWrite(ledPin3, LOW);
  } else {
  }
}

// say what you got:
// Serial.print("I received: ");
// Serial.println(incomingByte, DEC);
// }