string(247) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%BF%83%E7%8E%87%E9%87%87%E9%9B%86%E7%94%B5%E8%B7%AF%E7%9A%84%E8%AE%BE%E8%AE%A1 => Failed to connect to 14.18.117.71 port 38164: Connection refused"
心率采集电路的设计
