Arduino: Ping dengan hc sr04

Sumber: http://www.instructables.com/id/Easy-ultrasonic-4-pin-sensor-monitoring-hc-sr04/

Diagram

Code

int vcc  = 2; //attach pin 2 to vcc
int trig = 3; // attach pin 3 to Trig
int echo = 4; //attach pin 4 to Echo
int gnd  = 5; //attach pin 5 to GND

void setup() { 
    pinMode (vcc,OUTPUT);
    pinMode (gnd,OUTPUT);
    // initialize serial communication:
    Serial.begin(9600);
}

void loop() {
    digitalWrite(vcc, HIGH);
    // establish variables for duration of the ping,
    // and the distance result in inches and centimeters:
    long duration, inches, cm;
    
    // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
    // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
    pinMode(trig, OUTPUT);
    digitalWrite(trig, LOW);
    delayMicroseconds(2);
    digitalWrite(trig, HIGH);
    delayMicroseconds(5);
    digitalWrite(trig, LOW);  
    
    // The same pin is used to read the signal from the PING))): a HIGH
    // pulse whose duration is the time (in microseconds) from the sending
    // of the ping to the reception of its echo off of an object.
    pinMode(echo,INPUT);
    duration = pulseIn(echo, HIGH); 
     
    // convert the time into a distance
    inches = microsecondsToInches(duration);
    cm     = microsecondsToCentimeters(duration); 

    Serial.print(inches);
    Serial.print("in, ");
    Serial.print(cm);
    Serial.print("cm");
    Serial.println(); 
     
    delay(100);
} 

long microsecondsToInches(long microseconds)
{
    // According to Parallax's datasheet for the PING))), there are
    // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
    // second). This gives the distance travelled by the ping, outbound
    // and return, so we divide by 2 to get the distance of the obstacle.
    // See: http://www.parallax.com/dl/docs/prod/acc/28015-PI...
    return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{
    // The speed of sound is 340 m/s or 29 microseconds per centimeter.
    // The ping travels out and back, so to find the distance of the
    // object we take half of the distance travelled.
    return microseconds / 29 / 2;
}

Monitor

Hasil monitor akan keluar, seperti,

1838in, 4691cm
3in, 9cm
4in, 12cm
4in, 12cm
1842in, 4701cm
3in, 8cm
1818in, 4639cm
3in, 8cm
1823in, 4654cm
3in, 9cm
1832in, 4675cm

Referensi

• http://www.instructables.com/id/Easy-ultrasonic-4-pin-sensor-monitoring-hc-sr04/