程式碼部分：

void setup(){

Serial.begin(9600);

pinMode(9, OUTPUT);//trig

pinMode(10, INPUT);//echo

pinMode(7, OUTPUT);//蜂鳴器高電平

pinMode(4, OUTPUT);//蜂鳴器低電平

digitalWrite(4, LOW);

}

void loop(){

digitalWrite(9, LOW);

delayMicroseconds(2);

digitalWrite(9, HIGH);

delayMicroseconds(10);

digitalWrite(9, LOW);

float d = pulseIn(10, HIGH) / 58.00;

delay(10);

if(d<15){//距離小於15報警

digitalWrite(7, HIGH);

}

Serial.println(d);//串列埠列印距離

delay(80);

digitalWrite(7, LOW);

}