[Arduino]Day6-超音波感測器

下面範例是計算出距離後，如果距離大於100,就顯示其中一顆LED，沒有就另一顆亮

int ECHO_Pin=4;  // ultrasonic ECHO
int TRIG_Pin=5; // ultrasonic TRIG
int Near_LED = 9;
int Far_LED = 10;

void setup()
{
  Serial.begin(9600);
  pinMode(ECHO_Pin, INPUT);
  pinMode(TRIG_Pin, OUTPUT);
}
void loop()
{
  digitalWrite(TRIG_Pin, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_Pin, HIGH); // Pulse for 10 micro sec to trigger ultrasonic detection
  delayMicroseconds(10);
  digitalWrite(TRIG_Pin, LOW);
  int distance = pulseIn(ECHO_Pin, HIGH);  // Read receiver pulse time
  distance= distance/58;   // Transform pulse time to distance
  Serial.println(distance);   //Output distance

  if(distance > 100)
  {
    digitalWrite(Far_LED, HIGH);
    digitalWrite(Near_LED, LOW);
  }else{
    digitalWrite(Far_LED, LOW);
    digitalWrite(Near_LED, HIGH);
  }
  delay(50);
}



超音波模組運作原理
http://coopermaa2nd.blogspot.tw/2012/09/hc-sr04.html
http://mcudiy.blogspot.tw/2012/12/usm-ultrasonic-module-hc-sr04.html

datasheet
https://www.google.com.tw/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwjPxZqsgIrOAhUDEpQKHfkICa4QFggnMAI&url=http%3A%2F%2Fwww.micropik.com%2FPDF%2FHCSR04.pdf&usg=AFQjCNGQka2FGj3tvAzU2HEDfgZvvCQpNw&sig2=axF9GWdLv_KJdj3alHP1aA


DataSheet裡的波形圖

新學到的

PulseIn:量測input腳位的高電位或低電位脈波長度

https://www.arduino.cc/en/Reference/PulseIn