1、设计一个由甲、乙双方参赛，有裁判的3人乒乓球游戏机。

2、用8个(或更多个)LED排成一条直线，以中点为界，两边各代表参赛双方的位置，其中一只点亮的LED指示球的当前位置，点亮的LED依此从左到右，或从右到左，其移动的速度应能调节。

3、当“球”(点亮的那只LED)运动到某方的最后一位时，参赛者应能果断地按下位于自己一方的按钮开关，即表示启动球拍击球。若击中，则球向相反方向移动；若未击中，则对方得1分。

4、一方得分时，电路自动响铃3秒，这期间发球无效，等铃声停止后方能继续比赛。

5、设置自动记分电路，甲、乙双方各用2位数码管进行记分显示，每计满21分为1局。

6、甲、乙双方各设一个发光二极管，表示拥有发球权，每隔5次自动交换发球权，拥有发球权的一方发球才有效。-1, design a by A, B both sides of the competition, there are three referees table tennis game.

2, with 8 (or more) LED lined up in a straight line to the midpoint of the border, on both sides of the position on behalf of both sides of the competition, in which a light LED indicates the current location of the ball, From left to right, or　right to left, the speed of its movement should be able to adjust.

3, when the　ball　(the light of the LED) to move to the last of a party, the contestant should be able to decisively press the button on their side of the switch, which means starting racket hit. If hit, the ball moves in the opposite direction　if not hit, then the other 1 point.

4, a party scoring, the circuit automatically rings for 3 seconds, during which the serve is invalid, and so can stop the ring after the game.

5, set the automatic scoring circuit, A, B, the two sides with two digital tube score points show that each of 21 points into a Board.

6, A and B each set up a l