Read a FULL / NONE signal from an RC airplane receiver, and control an IO pin with it

rc_pwm.ino

void setup(){
  pinMode(4, OUTPUT);
  pinMode(5, INPUT);
  Serial.begin(9600);
}
 
void loop(){
  int length = pulseIn(5, HIGH);
  Serial.println(length);
  if(length < 1500) digitalWrite(4, LOW); // range is about 1000-2000 microseconds
  else digitalWrite(4, HIGH);
}