DHT11、DHT21系列的传感器小伙伴们一定很熟悉,单片机一接,写个小的APP,可以做个小型的室内温湿度监测系统。
材料清单:
元器件名称 | 数量 |
---|---|
DHT11 | 1 |
Respberry Pi Pico | 1 |
10k电阻 | 1 |
面包板 | 1 |
电气接线图:

Demo:
#include <stdio.h>
#include <math.h>
#include "pico/stdlib.h"
#include "hardware/gpio.h"
const uint LED_PIN = PICO_DEFAULT_LED_PIN;
const uint DHT_PIN = 15;
const uint MAX_TIMINGS = 85;
typedef struct {
float humidity;
float temp_celsius;
} dht_reading;
void read_from_dht(dht_reading *result);
int main() {
stdio_init_all();
gpio_init(LED_PIN);
gpio_init(DHT_PIN);
gpio_set_dir(LED_PIN, GPIO_OUT);
while (1) {
dht_reading reading;
read_from_dht(&reading);
float fahrenheit = (reading.temp_celsius * 9 / 5) + 32;
printf("Humidity = %.1f%%, Temperature = %.1fC (%.1fF)\n",
reading.humidity, reading.temp_celsius, fahrenheit);
sleep_ms(2000);
}
}
void read_from_dht(dht_reading *result) {
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);
gpio_put(LED_PIN, 1);
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++;
}
}
gpio_put(LED_PIN, 0);
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");
}
}
CMakelist.txt:
add_executable(dht
dht.c
)
target_link_libraries(dht pico_stdlib)
pico_add_extra_outputs(dht)
# add url via pico_set_program_url
example_auto_set_url(dht)
终端的输出如下:
