MEASURING DISTANCE TO OBSTACLE USING THE HC-SR04

Code:

Distance = rate * time
Time = PingTravelTime
Rate = speed of sound  miles per hour - need microseconds
Below
1 second = 1,000,000 micro seconds
I hour = 3600 seconds
Inches to mile
Feet 5280  = 1 mile
12 in = 1 foot


int Trig=A5;
int Echo=A4;
int pingT;
float targ00 secondsetDistance;
void setup() {
  // put your setup code here, to run once:
pinMode(Trig,OUTPUT);
pinMode(Echo,INPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
targetDistance=measDist();
Serial.println(targetDistance);
delay(500);

}

int pingTime(){
  int pingTravelTime;
  digitalWrite(Trig, LOW);   
  delayMicroseconds(2);
  digitalWrite(Trig, HIGH);  
  delayMicroseconds(20);
  digitalWrite(Trig, LOW);   
  pingTravelTime = pulseIn(Echo, HIGH);        
  return pingTravelTime; 
}
float measDist(){
  int pingTravelTime;
  float Dist;
  pingTravelTime=pingTime();
  Dist=(pingTravelTime*761.*5280.*12.)/(1000000.*3600.);
  Dist=Dist/2;
  return Dist;
}