基于DS18B20数字温度传感器的温度计C语言程序

好的，以下是基于DS18B20数字温度传感器的温度计C语言程序的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#define BUFFER_SIZE 256
#define DEVICE_PATH "/sys/bus/w1/devices/28-*/w1_slave"

float read_temperature(char *device_path) {
    int fd = open(device_path, O_RDONLY);
    if (fd == -1) {
        fprintf(stderr, "Failed to open device file: %s\n", device_path);
        return -1;
    }
    char buffer[BUFFER_SIZE];
    ssize_t num_read = read(fd, buffer, BUFFER_SIZE);
    if (num_read == -1) {
        fprintf(stderr, "Failed to read from device file: %s\n", device_path);
        close(fd);
        return -1;
    }
    char *pos = strstr(buffer, "t=");
    if (pos == NULL) {
        fprintf(stderr, "Unable to find temperature in buffer: %s\n", buffer);
        close(fd);
        return -1;
    }
    pos += 2;
    float temperature = strtof(pos, NULL) / 1000.0;
    close(fd);
    return temperature;
}

int main() {
    while (1) {
        char device_path[BUFFER_SIZE];
        sprintf(device_path, "%s", DEVICE_PATH);
        float temperature = read_temperature(device_path);
        if (temperature < 0) {
            fprintf(stderr, "Failed to read temperature from device: %s\n", device_path);
        } else {
            printf("Temperature: %.2f C\n", temperature);
        }
        sleep(1);
    }
    return 0;
}

这个程序首先定义了一些常量和需要用到的函数，然后在 `main()` 函数中不断读取温度并打印输出。`read_temperature()` 函数打开传感器的设备文件，读取原始数据并解析出摄氏温度值。在主程序中，我们循环读取所有传感器的温度并输出。注意，这个程序需要在树莓派上运行，并且需要在编译时链接 `libm` 库，以支持浮点数运算。