2-1 Quiz Buzzer

Summary
Description
Circuit Diagram
Components

Summary

Quiz games are becoming very popular these days. The main concept behind these games is the use of fastest finger first indicators which are used to test the reaction time of the contestants. When the players press the button then the designated player’s number is displayed with the use of audio-visual alarm. The project here has a circuit that can be used for 2 players or teams only. It can be used to identify which of the two has first pressed the button and locks out the other on. The project is made up of two 555 timers which are sometimes known as Schmitt trigger as they work in bistable state i.e. produce either a low or a high output. In this circuit when the trigger input is low the output of the circuit becomes high and when the reset input is low the output also becomes low.e.

Description

Both the contestants have a trigger push switch and a corresponding LED. Whenever any of the contestants press the switch, it triggers the bistable output (pin 3), the LED lights up and the beeper sounds due to which the other players switch stops working and it becomes easy to find that which switch was first pressed. In this a diode is used to link the output with the trigger line. Now the third switch comes into picture which is used to reset the circuit and it is with the quiz master. As soon as that switch is pressed the beeper gets cancelled and the LED turns off so that the circuit becomes ready for the next question.

Both the reset inputs are connected together and operated by a single reset switch. The switches for the contestants are connected to the bistable trigger so as to prevent quiz master from resetting the circuit until the trigger switches are released by the contestants. This bistable switch (pin 2) passes through a 0.1 µF capacitor so that only the primary pressing of the switch triggers the timer and then even if the switch is closed it has no effect. This is also known as edge triggering.

This circuit is designed for two teams only and if we want to increase the number of teams it is possible by adding the number of 555 timers.

Circuit Diagram

Components


12,380-Reads	Resistor Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it. They are omnipresent in electronic circuits. ...
8,758-Reads	Capacitor Capacitor is a passive component used to store charge. The charge (q) stored in a capacitor is the product of its capacitance (C) value and the voltage (V) applied to it. Capacitors offer infinite reactance to zero frequency so they are used for blocking DC components or bypassing the AC signals. The capacitor undergoes through a recursive cycl...
18,882-Reads	LED Light emitting diodes (LEDs) are semiconductor light sources. The light emitted...
20,073-Reads	Piezo Buzzer The piezo buzzer produces sound based on reverse of the piezoelectric effect. The generation of pressure variation or strain by the application of electric potential across a piezoelectric material is the underlying...
92,974-Reads	555 Timer IC 555 is a very commonly used IC for generating accurate timing pulses. It is an 8pin timer IC and has mainly two modes of operation: monostable and astable. In monostable mode time delay of the pulses can be precisely controlled by an external resistor and a capacitor whereas in astable mode the frequency & duty cycle are controlled by two external resistors and a...