DS18B20 Temp. Sensor

#include <stdio.h>
#include <dirent.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

int main (void) {
 DIR *dir;
 struct dirent *dirent;
 char dev = "28215"     // Dev ID
 char devPath[128]; // Path to device
 char buf[256];     // Data from device
 char tmpData[6];   // Temp C * 1000 reported by device 
 char path[] = "/sys/bus/w1/devices"; 
 ssize_t numRead;


      
 sprintf(devPath, "%s/%s/w1_slave", path, dev);


 
 while(1) {
  int fd = open(devPath, O_RDONLY);
  if(fd == -1)
  {
   perror ("Gerät wurde nicht gefunden");
   return 1;   
  }
  while((numRead = read(fd, buf, 256)) > 0) 
  {
   strncpy(tmpData, strstr(buf, "t=") + 2, 5); 
   float tempC = strtof(tmpData, NULL);
   printf("Device: %s  - ", dev); 
   printf("Temp: %.3f C  ", tempC / 1000);
   printf("%.3f F\n\n", (tempC / 1000) * 9 / 5 + 32);
  }
  close(fd);
 } 

}