Hands-On Robotics Programming with C++

The HC-SR04 sensor program

After wiring up the HC-SR04 sensor to the Raspberry Pi, let's write a program for measuring the distance between an object from an ultrasonic sensor. The distance measurement program is called DistanceMeasurement.cpp and you can download it from the Chapter04 folder of the GitHub repository.

The code for measuring the distance is as follows:

#include <stdio.h>#include <iostream>#include <wiringPi.h>using namespace std;#define trigger 12#define echo 13long startTime;long stopTime;int main(){ wiringPiSetup(); pinMode(trigger,OUTPUT); pinMode(echo, INPUT); for(;;){ digitalWrite(trigger,LOW); delay(500); digitalWrite(trigger,HIGH); delayMicroseconds(10); digitalWrite(trigger,LOW);  while(digitalRead(echo) == LOW); ...