초음파 거리센서 URM37 코딩
 
// # Editor    :Zrh from DFRobot
// # Data      :29.08.2014
// # Product name:ultrasonic scanner 
// # Product SKU:SEN0001
// # Version :  1.0
 
// # Description:
// # The sketch for using the URM37 autonomous  mode from DFRobot  
// #   and writes the values to the serialport
 
// # Connection:
// #       Vcc (Arduino)      -> Pin 1 VCC (URM V4.0)
// #       GND (Arduino)      -> Pin 2 GND (URM V4.0)
// #       Pin 3 (Arduino)    -> Pin 4 ECHO (URM V4.0)
// #       Pin TX1 (Arduino)  -> Pin 8 RXD (URM V4.0)
// #       Pin RX0 (Arduino)  -> Pin 9 TXD (URM V4.0)
// # Working Mode: autonomous  mode.
int URECHO = 3; // PWM Output 0－25000US，Every 50US represent 1cm
unsigned int x=0;
uint8_t EnPwmCmd[4]={0x44,0x02,0xaa,0xf0};    // distance measure command
 
void setup(){                                 // Serial initialization
  Serial.begin(9600);                         // Sets the baud rate to 9600
  AutonomousMode_Setup();
}
 
void loop()
{
 AutonomousMode();
 delay(100);
}                      //PWM mode setup function
 
void AutonomousMode_Setup(){ 
  pinMode(URECHO, INPUT);                      // Sending Enable PWM mode command
  for(int i=0;i<4;i++){
      Serial.write(EnPwmCmd[i]);
   } 
}
void AutonomousMode(){                              
    unsigned long DistanceMeasured=pulseIn(URECHO,LOW);
    if(DistanceMeasured>=45000){              // the reading is invalid.
      Serial.print("Invalid");    
   }
    else{
      x=DistanceMeasured/50;           // every 50us low level stands for 1cm
      Serial.print("Distance=");
      Serial.print(x);
      Serial.println("cm");
   }
  
}
 
 
 
 
이 코딩을 가지고
거리가 1.8m 이상일때는 흰색 점등 유지상태, 1.8m이하일때엔 빨간색이 1초간 점등되게 만들고 싶습니다.
 
if문을 활용하면 쉽다고 하는데 시도해봐도 실패해서 질문 드립니다.