说明：   用光电耦合器测量出重物下降过程中经过任何等距离且在同一垂直线上的三点时间间隔t1,t2,及距离h，然后利用公式g=2h(t1-t2)/t1t2(t1+t2)使用浮点数运算方法计算出g的值。最后由单片机p3口送串行显示。
(Optocoupler used to measure the process of heavy decline any equidistant and at the same vertical line of three time intervals t1, t2, and the distance h, and then use the formula g = 2h (t1-t2)/t1t2 (t12B ! t2) the use of floating-point method to calculate the value of g. Finally, I sent Singlechip p3 serial display.)