arduino ultrasonic

Specification:Working Voltage : 5V(DC)
Static Current: Less than 2mA.
Output Signal: Electric frequency signal, high level 5V, low level 0V.
Sensor Angle: Not more than 15 degrees.
Detection Distance: 2cm-400cm.
High Precision: Up to 0.3cm
Input Trigger Signal: 10us TTL impulse
Echo Signal : output TTL PWL signal



โค้ดตัวอย่างการใช้งาน

/*  HC-SR04 Ping distance sensor:  VCC to arduino 5v   GND to arduino GND  Echo to Arduino pin 7   Trig to Arduino pin 8  This sketch originates from Virtualmix: http://goo.gl/kJ8Gl  Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html  And modified further by ScottC here: http://arduinobasics.blogspot.com.au/2012/11/arduinobasics-hc-sr04-ultrasonic-sensor.html  on 10 Nov 2012.  */ 
#define echoPin 7 // Echo Pin 
#define trigPin 8 // Trigger Pin 
#define LEDPin 13 // Onboard LED 
int maximumRange = 200; // Maximum range needed 
int minimumRange = 0; // Minimum range needed 
long duration, distance; // Duration used to calculate distance 
void setup() 
{ 
 Serial.begin (9600); 
 pinMode(trigPin, OUTPUT); 
 pinMode(echoPin, INPUT); 
 pinMode(LEDPin, OUTPUT); // Use LED indicator (if required) 
} 
void loop() 
{ /* The following trigPin/echoPin cycle is used to determine the  distance of the nearest object by bouncing soundwaves off of it. */ digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 
 digitalWrite(trigPin, HIGH); 
 delayMicroseconds(10); 
 digitalWrite(trigPin, LOW); 
 duration = pulseIn(echoPin, HIGH); //Calculate the distance (in cm) based on the speed of sound. 
 distance = duration/58.2; 
if (distance >= maximumRange || distance <= minimumRange){ /* Send a negative number to computer and Turn LED ON   to indicate "out of range" */ 
 Serial.println("-1"); 
 digitalWrite(LEDPin, HIGH); 
} 
else { /* Send the distance to the computer using Serial protocol, and  turn LED OFF to indicate successful reading. */ 
 Serial.println(distance); digitalWrite(LEDPin, LOW); 
} //Delay 50ms before next reading. delay(50); 
}