中文说明：本程序用MATLAB读写串口。具体功能为读一个传感器。首先发送读指令，然后等待传感器反应。用MATLAB定时器定时，每秒读写1次。程序中使用了回调函数，包括串口接收回调函数和定时器回调函数。
English Description：
This program uses MATLAB to read and write serial port. The specific function is to read a sensor. First send read command, then wait for sensor response. Timer with MATLAB, read and write once per second. Callback functions are used in the program, including serial port receiving callback function and timer callback function.