"Lockout, Mr. Blackbeard!" game
74HC00, 74HC191, 74HC4028
In this project, you're going to stick a sword into the pirate Mr. Blackbeard locked in a barrel, competing with your fellows to first force him into a scream. This game uses keys in place of swords. You don't see a barrel, but you can hear a scream from Mr. Blackbeard.
When you finish wiring, make sure that the keys S1 - S8 are OFF, then turn power ON. Start by flicking Start.
LED 1 flashes a number of times, which depends on the time when S1 was pressed.
After LED 1 goes out, you're ready for the game. One of the keys S1 - S7 let Mr. Blackbeard scream. In a two-player game, for example, you and your opponent alternately press keys. If you pressed a key and heard a sound from the speaker, you won it.
To start the next round, you press S8 again, but this time, probably a different key is that key.
The counter U3 takes one of seven values. The value it has at a given time depends on the number of pulses from the NAND multivibrator U1.
When S8 is pressed and then released, U1 oscillates and sends clock pulses to the counter U3, until C1 is discharged. As such, this section comprises a random number generator. When this generator is operating, LED 1 stays lit.
The counter U3's outputs Q0 - Q3 are decoded by U4, so that one of Q0 - Q6 becomes High. When the High output is selected by pressing a key (one of S1 - S7 which are connected to Q0 - Q6), the NAND multivibrator U2 oscillates to generate a scream from the speaker.