Is there a way to simplify this circuit ? (2 players reaction tester game)

[tigrou]

This circuit is a 2 players reaction game.
The goal is to be the first to press a button after some random event (eg: buzz sound). This is not from me but from Kosmos 2000 electronic kit.



I was wondering if it was possible to do a 3 players (or more) version and ended with this.
While it works, it use 6 transistors and the 4 players version is going to use 12 transistors !
Is there a way to simplify it ? (eg: use less components)

[amyk]

Is there a way to simplify it ? (eg: use less components)

Use a microcontroller

[coromonadalix]

you have many possibilities, 555 based, transistor based. mcu   list goes on and on  etc ...

this one is simple in a way :
https://www.circuits-diy.com/school-college-quiz-buzzer-circuit-electronics-projects/

you can add many stages as you want ...   but simplicity mmm   

your  link does offer some simplicity too, you add more stages ...

[KrudyZ]

This circuit is a 2 players reaction game.
The goal is to be the first to press a button after some random event (eg: buzz sound). This is not from me but from Kosmos 2000 electronic kit.



I was wondering if it was possible to do a 3 players (or more) version and ended with this.
While it works, it use 6 transistors and the 4 players version is going to use 12 transistors !
Is there a way to simplify it ? (eg: use less components)

The problem with this circuit is that you also "win" by hitting the button before the event happens.
Also, why are the two base resistors of different value???

[tigrou]

Is there a way to simplify it ? (eg: use less components)

Use a microcontroller

Sure, but where is the fun ?

The problem with this circuit is that you also "win" by hitting the button before the event happens.

There is other flaws as well, like pressing all 3 buttons at once, then releasing the winning one (and still holding the 2 other buttons) might end up lighting 2 LEDs.
Maybe this only happen in the simulation (which is close to perfect unlike real world).

Also, why are the two base resistors of different value???

Probably because the kit only provide a limited set of resistors, so two different values had to be used.
The circuit is here.

you have many possibilities, 555 based, transistor based. mcu   list goes on and on  etc ...

this one is simple in a way :
https://www.circuits-diy.com/school-college-quiz-buzzer-circuit-electronics-projects/

you can add many stages as you want ...   but simplicity mmm   

your  link does offer some simplicity too, you add more stages ...

I like it. Thanks. I also start thinking about using a bunch of logic gates (usually multiple ones are packed in a single IC).

[jpanhalt]

I think you need a latch.  In Jeopardy, some (most) contestants hit the button and release.  That would allow a very close second place light to stay on if its button was held.

A switch debouncer circuit may work, but I second the micro as the simplest solution.  Plus, the micro will give you the option of showing reaction time in milliseconds.

[tigrou]

I think you need a latch.  In Jeopardy, some (most) contestants hit the button and release.  That would allow a very close second place light to stay on if its button was held.

A switch debouncer circuit may work, but I second the micro as the simplest solution.  Plus, the micro will give you the option of showing reaction time in milliseconds.

Something like that.

As a bonus :
- Reset pin is used to reset the whole thing
- D pin is used to prevent players pressing button before they are allowed to do so (input is ignored). Holding button before that signal will have no effect.

[jpanhalt]

That does seem to work and latches.  But, it's a lot of parts and still doesn't give the time.  Being the fastest of three is important, but an actual time that you can wear on an arm band is more impressive for bragging rights.

[tigrou]

Here is 555 version, based on coromonadalix answer.

Improved version of the OP circuit, using only transistors / resistors / diodes
There is probably lot of things to be improved (suggestions are welcome) but it's much better as it can scale easily.

[amyk]

If you don't want to use an MCU, how about a small CPLD?

[tigrou]

Challenge accepted 

Code: [Select]

module quizz (
    input wire reset,      
    input wire enabled,
    input wire player1,    
    input wire player2,    
    input wire player3,    
    output reg led1,       
    output reg led2,       
    output reg led3        
);
  wire allowed = !(led1 | led2 | led3) && enabled; 

  always @(posedge player1 or posedge reset) begin
      if (reset) begin
            led1 = 1'b0;
        end else begin
            led1 = allowed;
        end
    end
  
  always @(posedge player2 or posedge reset) begin
      if (reset) begin
            led2 = 1'b0;
        end else begin
            led2 = allowed;
        end
    end  
  
  always @(posedge player3 or posedge reset) begin
      if (reset) begin
            led3 = 1'b0;
        end else begin
            led3 = allowed;
        end
    end    

endmodule

Can be tested here

The synthetized layout is as simple as it can be :

[jimmc]

How about this, can be expanded as required

[DavidAlfa]

Here you have, unlimited players, zero parts, the one that touches enables a very bright indicator.

[tigrou]

How about this, can be expanded as required

Works like a charm.

Here you have, unlimited players, zero parts, the one that touches enables a very bright indicator.

(Attachment Link)