说明：  实现继电器开关在市电的零点闭合，以延长继电器的使用寿命。（基于ATMEL单片机 ATTiny13 由AVR studio编写）
(Realize the relay switch in the closed city against electricity to extend the life of the relay. (Based on the ATMEL Singlechip ATTiny13 prepared by the AVR studio))