라즈베리파이3 B+ 초음파 센서 HC-SR04 테스트 C코드

센서와 연결도 참고사진

 

 

 

소스코드

 

#include<stdio.h>
#include<wiringPi.h>

#define trigPin 29	//gpio 21
#define echoPin 1	//gpio 18

//old #define trigPin 21	//gpio 5
//old #define echoPin 4	//gpio  J16-pin3 GPIO 23

int main(void)
{
	int distance=0;
	int pulse = 0;
	
	long startTime;
	long travelTime;
	
	if(wiringPiSetup () == -1)
	{
		printf("Unable GPIO Setup"); 
		return 1;
	}
		
	pinMode (trigPin, OUTPUT);
	pinMode (echoPin, INPUT);
	
	for(;;)
	{
		digitalWrite (trigPin, LOW);
		usleep(2);
		digitalWrite (trigPin, HIGH);
		usleep(20);
		digitalWrite (trigPin, LOW);
		
		while(digitalRead(echoPin) == LOW);
		
		startTime = micros();
		
		while(digitalRead(echoPin) == HIGH);
		travelTime = micros() - startTime;
		
		int distance = travelTime / 58;
		
		printf( "Distance: %dcm\n", distance);
		delay(200);
	}
}