--->>> 예제 dth11.c  <<<-----------------------------------
#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#define MAXTIMINGS 83
#define DHTPIN 7

int dht11_dat[5] = {0, } ;

void read_dht11_dat()
{
  uint8_t laststate = HIGH ;
  uint8_t counter = 0 ;
  uint8_t j = 0, i ;
  uint8_t flag = HIGH ;
  uint8_t state = 0 ;
  float f ;
  dht11_dat[0] = dht11_dat[1] = dht11_dat[2] = dht11_dat[3] = dht11_dat[4] = 0 ;

  pinMode(DHTPIN, OUTPUT) ;
  digitalWrite(DHTPIN, LOW) ;
  delay(18) ;

  digitalWrite(DHTPIN, HIGH) ;
  delayMicroseconds(30) ;
  pinMode(DHTPIN, INPUT) ;

  for (i = 0; i < MAXTIMINGS; i++) {
    counter = 0 ;
    while ( digitalRead(DHTPIN) == laststate) {
      counter++ ;
      delayMicroseconds(1) ;
      if (counter == 200) break ;
    }
    laststate = digitalRead(DHTPIN) ;
    if (counter == 200) break ; // if while breaked by timer, break for
    if ((i >= 4) && (i % 2 == 0)) {
      dht11_dat[j / 8] <<= 1 ;
      if (counter > 20) dht11_dat[j / 8] |= 1 ;
      j++ ;
    }
  }

  if ((j >= 40) && (dht11_dat[4] == ((dht11_dat[0] + dht11_dat[1] + dht11_dat[2] + dht11_dat[3]) & 0xff))) {
    printf("humidity = %d.%d %% Temperature = %d.%d *C \n", dht11_dat[0], dht11_dat[1], dht11_dat[2], dht11_dat[3]) ;
  }
  else printf("Data get failed\n") ;
}

int main(void)
{
  printf("dht11 Raspberry pi\n") ;
  if (wiringPiSetup() == -1) exit(1) ;

  while (1) {
    read_dht11_dat() ;
    delay(1000) ;
  }
  return 0 ;
}
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$ gcc  -o  dht11  dht11.c  -lwiringPi
$ sudo ./dht11_cprog