Shooting game II
74HC00, 74HC02, 74HC191, 74HC4028
With the game you're going to build in this project, LEDs 1-8 light in rapid succession and you must shoot LED 8 to make a hit. If you shoot it right, you'll be awarded with a monotone from the speaker. The trigger of your gun is the key S1. Are you a good shooter?
When you finish wiring, make your finger ready for pressing the key S1, then turn power ON. You'll see LEDs 1-8 lighting in turn. Press S1 while LED 8 is lighting. If you did it right, a monotone sounds from the speaker.
After LED 8 lights, all LEDs go out to finish the game. To restart the game, press the start key S5.
The counter U2 counts up with the pulses from the NAND multivibrator U1.
The output of the counter U2 is decoded by the decoder U3, so that LEDs 1-8 light one after another.
When S1 is pressed, the R-S flip-flop U1 is set, and R5 and C3 cause the NAND gate U4 to put out a pulse. If this pulse occurs during lighting of LED 8, the output of U4 stays H for a certain period, so that the NAND multivibrator U5 oscillates to sound a monotone from the speaker. When the start key S5 is pressed, the value of the counter U2 is cleared to 0 and also the R-S flip-flop U1 is reset.