帮我写个树莓派对DS18B20温度传感器自检的程序

好的，这个问题可以回答。以下是一个简单的 Python 代码示例，可用于自检 DS18B20 温度传感器：

import os

def read_temp_raw(sensor_id):
    device_folder = '/sys/bus/w1/devices/' + sensor_id
    device_file = device_folder + '/w1_slave'
    with open(device_file, 'r') as f:
        lines = f.readlines()
    return lines

def read_temp(sensor_id):
    lines = read_temp_raw(sensor_id)
    while lines[0].strip()[-3:] != 'YES':
        time.sleep(0.2)
        lines = read_temp_raw(sensor_id)
    equals_pos = lines[1].find('t=')
    if equals_pos != -1:
        temp_string = lines[1][equals_pos+2:]
        temp_c = float(temp_string) / 1000.0
        return temp_c

sensor_id = '28-xxxxxxxxxxxx'  # 根据实际设备 ID 修改
temp = read_temp(sensor_id)
print('当前温度为：{:.1f} ℃'.format(temp))