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push button circuit for quiz

Discussion in 'General Electronics Discussion' started by Vikkstar123, Sep 19, 2015.

  1. Vikkstar123

    Vikkstar123

    3
    0
    Sep 19, 2015
    I need a block diagram for this project please.
    This project can be used for a quiz with up to 4 contestants (or teams). Each contestant has a trigger push-switch and LED. When a trigger switch is pressed it lights the corresponding LED, sounds the bleeper and prevents the other trigger switches from working - therefore showing which contestant was the first to press their switch. A reset push-switch (operated by the quizmaster) cancels the bleeper and switches off the LED so the circuit is ready for the next question.

    Take great care to arrange the parts correctly on the compact stripboard layout. The LEDs are shown mounted directly on the stripboard but you may prefer to mount them on a box using short wires. The trigger switches need long cables of about 2 metres so they can be held by, or placed near, the contestants.
    The circuit consists of four 555 timer bistables which are triggered or reset when their inputs are low. Their reset inputs are connected together and operated by a single reset push-switch. The trigger switches are connected to the bistable trigger (pin 2) through a 0.1µF capacitor so that only the initial press triggers the bistable; continuing to hold the switch closed will have no effect. This is callededge triggering.

    Connecting the switch directly to the bistable would prevent the quizmaster from resetting the circuit until the trigger switch was released and trials showed that many contestants kept the switch pressed until asked to give their answer! When triggered the bistable output (pin 3) lights an LED and makes the 'trigger line' high - this prevents any other bistable being triggered and sounds the bleeper. A diode is used to link the output to the trigger line.
     
  2. Arouse1973

    Arouse1973 Adam

    5,164
    1,078
    Dec 18, 2013
    Hello

    You need to supply a block diagram and we help you with the circuit, that's how it works! When you say the project can be used for a quiz game, what else can it be used for? Is this homework?

    Do you have to use 555 timers?

    Thanks
    Adam
     
  3. Martaine2005

    Martaine2005

    2,372
    626
    May 12, 2015
    Hi vikkstar123,
    This should give you some good ideas.
    There are a few around the forum. Click on ADAM.

    Martin
     
    Arouse1973 likes this.
  4. AnalogKid

    AnalogKid

    2,289
    646
    Jun 10, 2015
    There are many quiz show circuits on the innergoogle, some dating back to the 50's. While it can be done with a bank of 555's, there are many better ways. You instructions sound like they were copied from a project on a website. Can you post a link to the original information, or at least the schematic?

    Way back, the first project I built for someone other than myself was a quiz show circuit. The circuit linked in post#3 deserves an award.

    ak
     
    Arouse1973 and Martaine2005 like this.
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