Danger-alarm/SOFTWARE/Source/DTH11.cpp

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1.7 KiB
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2024-06-03 16:27:41 +08:00
#include "DTH11.hpp"
typedef struct {
float humidity;
float temp_celsius;
} dht_reading;
void read_from_dht(dht_reading * result, int DHT_PIN)
{
int data[5] = { 0, 0, 0, 0, 0 };
uint last = 1;
uint j = 0;
gpio_set_dir(DHT_PIN, GPIO_OUT);
gpio_put(DHT_PIN, 0);
sleep_ms(20);
gpio_set_dir(DHT_PIN, GPIO_IN);
for (uint i = 0; i < MAX_TIMINGS; i++) {
uint count = 0;
while (gpio_get(DHT_PIN) == last) {
count++;
sleep_us(1);
if (count == 255)
break;
}
last = gpio_get(DHT_PIN);
if (count == 255)
break;
if ((i >= 4) && (i % 2 == 0)) {
data[j / 8] <<= 1;
if (count > 16)
data[j / 8] |= 1;
j++;
}
}
if ((j >= 40) && (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF))) {
result->humidity = (float)((data[0] << 8) + data[1]) / 10;
if (result->humidity > 100) {
result->humidity = data[0];
}
result->temp_celsius = (float)(((data[2] & 0x7F) << 8) + data[3]) / 10;
if (result->temp_celsius > 125) {
result->temp_celsius = data[2];
}
if (data[2] & 0x80) {
result->temp_celsius = -result->temp_celsius;
}
} else {
printf("Bad data\n");
}
}
int DTH11_(int DHT_PIN)
{
stdio_init_all();
gpio_init(DHT_PIN);
dht_reading reading;
read_from_dht(&reading, DHT_PIN);
float fahrenheit = (reading.temp_celsius * 9 / 5) + 32;
printf("Humidity = %.1f%%, Temperature = %.1fC (%.1fF)\n", reading.humidity, reading.temp_celsius, fahrenheit);
sleep_ms(2000);
return 0;
}