int trigger = 4; // PWM signal arduino pin
int led = 13;
int button = 12;
int leds_front = 9;
int leds_back = 8;
int chn2 = 0;    // Receiver channel 2 pwm value
int chn3 = 0;    // Receiver channel 3 pwm value

void setup() {
  pinMode(trigger, INPUT);
  pinMode(button, INPUT);
  Serial.begin(9600);
  pinMode(led, OUTPUT);
  pinMode(leds_front, OUTPUT);
  pinMode(leds_back, OUTPUT);

}

void loop() {
  // Read in the length of the signal in microseconds
  chn3 = pulseIn(button, HIGH, 25000);
  Serial.print("Channel #3: ");
  Serial.println(chn3);
  chn2 = pulseIn(trigger, HIGH, 25000);
  Serial.print("Channel #2: ");
  Serial.println(chn2);
  
 // if ( chn3 < 1500)
 //     blink2(leds_front, leds_back);

  if((chn2 >= 1480) && (chn2 <= 1500)){
    blinking(leds_front, leds_back);

  }else if ( chn2 > 1500){
    digitalWrite(leds_back, HIGH);
  }else if (chn2 < 1480)
     digitalWrite(leds_front, HIGH);
     
     if ( chn3 < 1500)
      blink2(leds_front, leds_back);

}

void blinking (int ld_f, int ld_b){
  digitalWrite(ld_f, HIGH);
  digitalWrite(ld_b, HIGH);
  delay(100);
  digitalWrite(ld_f, LOW);
  digitalWrite(ld_b, LOW);
  delay(100);
}

void blink2(int ld_f, int ld_b){
    digitalWrite(ld_f, HIGH);
  digitalWrite(ld_b, LOW);
  delay(200);
  digitalWrite(ld_f, LOW);
  digitalWrite(ld_b, HIGH);
  delay(200);
}