通过ATmel公司的mega328p芯片作为核心，使用4段移位数码管，通过usb连接电脑串口。用arduino的串口侦查器发送命令实现：
1.显示任何4位数（含小数）。
2.对改数进行末位加一（不进位）。
3.对改数进行乘十，当到达无小数点时自动变成除十，当小到无法显示自动变成乘十。
4.循环左移和循环右移（小数点位置不变）。(Through ATmel company's mega328p chip as the core, the use of 4 segment digital tube, through the USB connection computer serial port. Using Arduino serial detector to send commands to achieve:
1. displays any 4 digits (including decimals).
2. of the number of the last plus one (not carry).
3. the number of changes to multiply ten, when the arrival of no decimal point, automatically changed to ten, when it is too small to display automatically become ten.
4. loop moves left and the loop moves right (where the decimal point remains unchanged).)