3 buttons and 3 LEDs circuit with mutual exclusion

Question

I want to create a simple game for 3 players with 3 push buttons and 3 LEDs. Each button turns on a specific LED. The challenging part is that I need mutual exclusion. Only the LED corresponding to the first button pressed should light up, and the others should remain off.

The game concept is this: A question is shown to 3 students. The first student who knows the answer presses their button and turns on their corresponding LED. Basically, I need to know who pressed first.

My knowledge on electronic is very basic (welding a few components) however I can learn anything, and I'm looking to the simplest way to accomplish this.

Answer 1

Here's one of many ways. It's modular, so you add as many students as needed. Personally, I would probably do this with a microcontroller dev board or Arduino. But here's a hardware only version if you want to build something without software:

^{simulate this circuit – Schematic created using CircuitLab}

Answer 2

As above, this is called a "game show" or "College Bowl" circuit. If you search for 'game show circuit' or game show circuit schematic', you will get many examples of how to do this.

Answer 3

This is the classic "game show" or "Jeopardy" circuit. The first button pressed is registered and locks out any subsequent presses of all other buttons, until a master reset arrives. Over the years, many circuits have been devised for this application, here are just two examples:

This one uses discrete components, specifically SCRs. An SCR can be created using small-signal BJT:
https://forum.allaboutcircuits.com/threads/gameshow-buzzers-how-can-i-illuminate-only-the-first-pressed-button.184475/#post-1701696

This one uses logic gates:
https://forum.allaboutcircuits.com/threads/game-circuit.82641/

A search for "game show first button push" will yield a plethora of results from which to choose from.

Without knowing any other details about your particular application I cannot help further. Details needed to select/design a suitable circuit are:

1. What power supply will be used. Battery or mains operated?
2. Mechanical form-factor required, including the inputs (buttons) and outputs (LEDs). This will determine things like buttons, LEDs, housing, interconnecting cables, radio-links, etc.
3. Interfacing - does this need to provide outputs to some external system?
4. Cost constraints, and production qty. Is this a one-off, or are you planning to make thousands? Selling into various markets requires compliance testing and certification, which can add significant costs to product development.