Quiz Game Show Buzzer using Arduino

I’ve decided to try my idea with an Arduino prototype.

The different buttons are for each “team” and for the master of the game to accept or reject an answer, giving the point to the team answering the question or not.

The leds lit up to know which team can currently answer.

The speaker plays a little tune… but it’s not amplified, so it’s not very loud.

The display shows the current score for each teams.

Step 4: The Code

So… I’m including my code, but I’m not explaining it… and yes I know there is no comments… if you have questions, feel free to ask me, but I didn’t do this to make a programming tutorial.

First you need to include “pitches.h”… but to be able to include it, you need to get it from here… Arduino Tone Tutorial

#include “pitches.h”

Then let’s define some arrays to help ourselves for later when we need to use the 8 digits 7 segments display

// array to activate particular digit on the 8x7segment module<br>// it is the common anode of 7 segment
byte digit[8] = { 
  0b10000000,  //digit 1 from right
  0b01000000,  //digit 2 from right
  0b00100000,  //digit 3 from right
  0b00010000,  //digit 4 from right
  0b00001000,  //digit 5 from right
  0b00000100,  //digit 6 from right
  0b00000010,  //digit 7 from right
  0b00000001   //digit 8 from right                                         
};
<br><p>//array for decimal number, it is the cathode, please refer to the datasheet.
//therefore a logic low will activete the particular segment
//PGFEDCBA, segment on 7 segment, P is the dot
byte number[12] = {
  0b11000000,  // 0
  0b11111001,  // 1
  0b10100100,  // 2
  0b10110000,  // 3
  0b10011001,  // 4
  0b10010010,  // 5
  0b10000010,  // 6
  0b11111000,  // 7
  0b10000000,  // 8
  0b10010000,  // 9  
  0b01111111,  //dot                  
  0b11111111   //blank
};</p>

We should also define some constants that will help us identify input and output pins later in the code

const int blueLEDPin = 12;
const int greenLEDPin = 11;
const int redLEDPin = 10;
const int yellowLEDPin = 9;

const int teamPinDiff = 5;  //to help with computations later<

const int blueButton = 17;
const int greenButton = 16;
const int redButton = 15;
const int yellowButton = 14;
const int acceptButton = 18;
const int refuseButton = 19;

const int speakerPin = 8;

const int latchPin = 7;  //connect to RCK of 8x7segment module 
const int clockPin = 6;  //connect to SCK of 8x7segment module 
const int dataPin = 5;  //connect to DIO of 8x7segment module

const int multiplexDelay = 1;

const int dotNumber = 10;
const int blankNumber = 11;

We also need to keep some variables to know what’s going on in the program

int currentTeam = 0;
int blueScore = 0;
int greenScore = 0;
int redScore = 0;
int yellowScore = 0;byte blueDigit1 = number[blankNumber];
byte blueDigit2 = number[0];
byte greenDigit1 = number[blankNumber];
byte greenDigit2 = number[0];
byte redDigit1 = number[blankNumber];
byte redDigit2 = number[0];
byte yellowDigit1 = number[blankNumber];
byte yellowDigit2 = number[0];

Then we setup the pin modes and the display

void setup()
{  
  pinMode(blueLEDPin, OUTPUT);
  pinMode(greenLEDPin, OUTPUT);
  pinMode(redLEDPin, OUTPUT);
  pinMode(yellowLEDPin, OUTPUT);
  pinMode(blueButton, INPUT);
  pinMode(greenButton, INPUT);
  pinMode(redButton, INPUT);
  pinMode(yellowButton, INPUT);
  pinMode(acceptButton, INPUT);
  pinMode(refuseButton, INPUT);
  pinMode(speakerPin, OUTPUT);
  
  digitalWrite(blueLEDPin, LOW);
  digitalWrite(greenLEDPin, LOW);
  digitalWrite(redLEDPin, LOW);
  digitalWrite(yellowLEDPin, LOW);
  
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  digitalWrite(latchPin, HIGH);
}

And we create the loop function that will run after setup

void loop() 
{
  ProgramLoop();
  WriteScore();
}

As you see, I’ve created functions to separate my code a bit better… so let’s create those functions

void ProgramLoop()
{
  if (currentTeam == 0) {
    if (digitalRead(blueButton) == HIGH) {
      currentTeam = blueLEDPin;
      PlayAnswerBlue();
    }
    else if (digitalRead(greenButton) == HIGH) {
      currentTeam = greenLEDPin;
      PlayAnswerGreen();
    }
    else if (digitalRead(redButton) == HIGH) {
      currentTeam = redLEDPin;
      PlayAnswerRed();
    }
    else if (digitalRead(yellowButton) == HIGH) {
      currentTeam = yellowLEDPin;
      PlayAnswerYellow();
    }
  }
  else
  {
    digitalWrite(currentTeam, HIGH);
    if (digitalRead(currentTeam + teamPinDiff) == LOW) {
      if (digitalRead(acceptButton) == HIGH) {
        PlayAccept();
        IncrementScore();
      }
      else if (digitalRead(refuseButton) == HIGH) {
        PlayDeny();
        ResetState();
      }
    }
  }
}

void ResetState()
{
  currentTeam = 0;
  digitalWrite(blueLEDPin, LOW);
  digitalWrite(greenLEDPin, LOW);
  digitalWrite(redLEDPin, LOW);
  digitalWrite(yellowLEDPin, LOW);
}

void IncrementScore()
{
  switch (currentTeam) {
  case blueLEDPin:
    blueScore++;
    if (blueScore > 9) {
      if (blueScore > 99) {
        blueScore = 0;
      }
      blueDigit1 = number[blueScore / 10];
    }
    blueDigit2 = number[blueScore % 10];
    break;
  case greenLEDPin:
    greenScore++;
    if (greenScore > 9) {
      if (greenScore > 99) {
        greenScore = 0;
      }
      greenDigit1 = number[greenScore / 10];
    }
    greenDigit2 = number[greenScore % 10];
    break;
  case redLEDPin:
    redScore++;
    if (redScore > 9) {
      if (redScore > 99) {
        redScore = 0;
      }
      redDigit1 = number[redScore / 10];
    }
    redDigit2 = number[redScore % 10];
    break;
  case yellowLEDPin:
    yellowScore++;
    if (yellowScore > 9) {
      if (yellowScore > 99) {
        yellowScore = 0;
      }
      yellowDigit1 = number[yellowScore / 10];
    }
    yellowDigit2 = number[yellowScore % 10];
    break;
  }
  ResetState();
}

void WriteScore()
{
  display8x7segment(digit[0], number[dotNumber]);
  display8x7segment(digit[0], blueDigit2);
  display8x7segment(digit[1], blueDigit1);
  display8x7segment(digit[2], number[dotNumber]);
  display8x7segment(digit[2], greenDigit2);
  display8x7segment(digit[3], greenDigit1);
  display8x7segment(digit[4], number[dotNumber]);
  display8x7segment(digit[4], redDigit2);
  display8x7segment(digit[5], redDigit1);
  display8x7segment(digit[6], number[dotNumber]);
  display8x7segment(digit[6], yellowDigit2);
  display8x7segment(digit[7], yellowDigit1);
}

void display8x7segment(byte digit, byte number)
{
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digit); // clears the right display
  shiftOut(dataPin, clockPin, MSBFIRST, number); // clears the left display
  digitalWrite(latchPin, HIGH);  
  delay(1);
}

void PlayAnswerBlue() 
{
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_C5, 100);
  delay(25);
  beep(speakerPin, NOTE_C5, 100);
  delay(25);
  beep(speakerPin, NOTE_C5, 100);
}

void PlayAnswerGreen() {
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_D5, 100);
  delay(25);
  beep(speakerPin, NOTE_D5, 100);
  delay(25);
  beep(speakerPin, NOTE_D5, 100);
}

void PlayAnswerRed() {
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_E5, 100);
  delay(25);
  beep(speakerPin, NOTE_E5, 100);
  delay(25);
  beep(speakerPin, NOTE_E5, 100);
}

void PlayAnswerYellow() {
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_F5, 100);
  delay(25);
  beep(speakerPin, NOTE_F5, 100);
  delay(25);
  beep(speakerPin, NOTE_F5, 100);
}

void PlayAccept() {
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_C5, 75);
  delay(10);
  beep(speakerPin, NOTE_D5, 75);
  delay(10);
  beep(speakerPin, NOTE_E5, 75);
  delay(10);
  beep(speakerPin, NOTE_G5, 75);
  delay(10);
  beep(speakerPin, NOTE_E5, 75);
  delay(10);
  beep(speakerPin, NOTE_G5, 75);
  delay(10);
  beep(speakerPin, NOTE_C6, 75);
}

void PlayDeny() {
  display8x7segment(digit[7], number[blankNumber]);
  beep(speakerPin, NOTE_A4, 1000);
}

void beep (unsigned char speakerPin, int frequencyInHertz, long timeInMilliseconds)
{
  int x;      
  long delayAmount = (long)(1000000/frequencyInHertz);
  long loopTime = (long)((timeInMilliseconds*1000)/(delayAmount*2));
  for (x=0; x < loopTime; x++)
  {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(delayAmount);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(delayAmount);
  }
}

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