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  • Game Buzzer (Answer/Finish First) Circuit

  • Created: Oct 02, 2014

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The game buzzer project is designed for competition gameplay. This system notifies all the competitors that one of them had pressed a designated button first. This is used for games with crucial time like quiz-bee. The number assigned to each competitors will also be revealed on the display panel. And the notification is accomplished Through an audio signaling device, buzzer.

This project is playable up to 8 competitors, assigned with each single switch. initial setup of the project is to press the reset switch of the N74F373D Octal transparent latch, which will set all its output to HIGH. All eight outputs of N74F373D are connected to inputs of priority encoder 74HC147D 10-to-4 line priority encoder as well as 8-input NAND gate N74F30D. After inversion by NAND gate N2, the output of N74F30D thus becomes LOW which is applied to latch-enable pin 11 of N74F373D. With all input pins of 74HC147D being HIGH, its BCD output will be "0000", which is inputted to the 7-segment driver HEF4511BT after inversion by hex inverter gates inside N74F04D. When one of the buttons are switched, the corresponding output line of the N74F373D is latched at LOW level and the display indicates the number associated with the specific switch. When the output of N74F30D becomes high, which causes outputs of both 74AHC2G00DP gates N1 and N2 to go to LOW state. LOW output of gate N2 inhibits N74F373D, thus pressing of any other switch is disabled. And the LOW output of gate N1 drives the buzzer via BC547 pnp transistor. The buzzer as well the display can be reset by pressing of reset switch for the next round to start.



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