设计一个心率检测计， 能够使用单片机实时显示当前被检测人的
心率。老师提供红外传感器，需要自行设计接收到变化信号后的
放大电路及单片机实时计算心率的程序(Heart rate meter
A heart rate detector can be used to display the current person in real time using a single chip computer.
Heart rate. The teacher provides an infrared sensor that needs to be designed to receive the change signal.
A program for real-time calculation of heart rate by amplifying circuit and single chip microcomputer)