显示行驶时间,将所测转速显示在数码管。 金属检测传感器。每检测到一次金属就产生中断一次，蜂鸣器报警，小车停止5秒，记录金属数量和保存转的圈速。 -Display with time, the measured speed is displayed in digital Metal detection sensor. Each time the metal is detected an interrupt is generated once, the buzzer alarm, the