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

#define MAXTIMINGS 85
#define DHTPIN 7

int dht11_dat[5] = { 0, 0, 0, 0, 0 };

void read_dht11_dat() {
    uint8_t laststate = HIGH;
    uint8_t counter = 0;
    uint8_t j = 0, i;
    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(40);

    pinMode(DHTPIN, INPUT);

    for (i = 0; i < MAXTIMINGS; i++) {
        counter = 0;
        while(digitalRead(DHTPIN) == laststate) {
            counter++;
            delayMicroseconds(1);
            if (counter ==255) break;
        }

        laststate = digitalRead(DHTPIN);

        if (counter == 255)
            break;

        if ((i >= 4) && (i % 2 == 0)) {
            dht11_dat[j/8] <<= 1;
            if (counter > 16)
                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 ))) {
        f = dht11_dat[2] * 9. / 5. + 32;
        printf("Humidity = %d.%d %% Temperature = %d.%d C (%.1f F)\n",
               dht11_dat[0], dht11_dat[1], dht11_dat[2], dht11_dat[3], f);
    } else {
        printf("Data not good, skip \n");
    }
}

int main(void) {
    printf("Raspberry Pi wiriingPi DHT11 Temperature test program\n");

    if (wiringPiSetup() == -1) {
        exit(-1);
    }
    while (1) {
        read_dht11_dat();
        delay(1000);
    }

    return(0);
}