#define SENSOR_IR   2
#define DRV_OUTPUT  3 

void setup() {
  pinMode(SENSOR_IR, INPUT_PULLUP);
  pinMode(DRV_OUTPUT,OUTPUT);
  // put your setup code here, to run once:

} 

void loop() {

  if(!status_sensorIR(SENSOR_IR))
  {
    enable_actuator(HIGH);
  }
  else
  {
    enable_actuator(LOW);
  }

  delay(500);
  // put your main code here, to run repeatedly:

}

int status_sensorIR(int pin)
{
  return digitalRead(pin);
}

void enable_actuator(int status)
{
  digitalWrite(DRV_OUTPUT,status);
}