This highly portable electronic pocket pinbaIl game circuit may not exactly be a substitute for its big brothers in the amusement arcades, but it still provides a lot of fun. The circuit is relatively simple: three CMOS ICs, nine LEDs, six resistors, one capacitor, one push- button and a 9 V battery. Together with R1, R2 and C1, NOR gates N1 . . . N3 form a clock generator whose signal is applied to decimal counter lC3. For as long as the player presses pushbutton S1, clock pulses are counted. When the button is released, the counter is inhibited for the incoming clock signals and only one of LEDs D1 . . . D7 will light. The carry output of the decimal counter toggles flip-flops FF1 and FF2 which are configured as 2-bit binary counters. Depending on the counter status, the player is entitled to a free ball (LED D8 lights) or he can double the score (LED D9 lights). Obviously, this simple circuit is not equipped with a points counter. The points gained by each player must therefore be noted on a piece of paper. The values are indicated next to the corresponding LEDs on the circuit diagram. If only one of LEDs D5. . . D7 lights, the ball is out of play; with '0’ it was through g the middle, and with '25’ to the { right or left. It is then the turn of l the next player. If, however, D8 lights in addition to the '25' LED, the player has gained a free ball. He can try his luck again. With a little care, the front panel of this electronic pinball game circuit can be designed with the LEDs positioned in such a way that the game resembles the full-scale pinball machine .
