Using wireless would be difficult if contestants ring in at the same time.
This was discussed awhile back using a wired network:
/*jeopardy style game-- master button (masClick) will enable 20+ other buttons (chiClick) to "buzz" in.
Once a player button is pressed, the others are locked out and the player's corresponding LED is lit indicating
which player buzzed in first. The loop resets after 5 seconds and waits for the master to be pressed again.
*/
//LarryD
#define pushed LOW //pushing gives a LOW
//#define pushed HIGH //pushing gives a HIGH
#define LEDon HIGH
#define LEDoff LOW
const byte masClick = 53; // iteration should commence once masClick pin 53 goes HIGH
const byte masClickLED = 52; // will illuminate when master button is pressed
const byte chiClick[] = { 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23};
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
const byte chiClickLED[] = {24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45};
const byte pinCount = 22;
const unsigned int onTime = 5000; //after you have a winner leave LED on for this time
const unsigned int debounceDelay = 25; //scans switches every 25 milliseconds
unsigned long debounceMillis; //used in timing switch checking
unsigned long FiveSecMillis; //used in timing after first person has been detected
unsigned long masterMillis; //used for flashing master LED after cheating is detected
unsigned long delayMillis; //used after cheating has been acknowledgment by master push
unsigned long winnerMillis; //used in timing to flash the winners LED
byte winnerIndex; //the array index number of the winner
bool FiveSecFlag = false; //false = not in 5 second timing mode
bool polingFlag = false; //flase = not scanning the contestant switches
bool cheatFlag = true; //true = check to see if contestant button is pressed before it should be
bool flashFlag = false; //false = flash the master LED
//*********************************************************
void setup()
{
pinMode(masClick, INPUT_PULLUP);
pinMode(masClickLED, OUTPUT);
digitalWrite(masClickLED, LEDoff);
for (int i = 0; i < pinCount; i++)
{
pinMode(chiClick[i], INPUT_PULLUP);
pinMode(chiClickLED[i], OUTPUT);
digitalWrite(chiClickLED[i], LEDoff);
}
//Lamp test, flash LEDs 10 times at reset, an even number here leaves the LEDs off
for (int x = 0; x < 20; x++)
{
for (int i = 0; i < pinCount; i++)
{
digitalWrite(chiClickLED[i], !digitalRead(chiClickLED[i]));
}
digitalWrite(masClickLED, !digitalRead(masClickLED));
delay(500);
}
} //END of s e t u p ( )
//*********************************************************
void loop()
{
//NON-blocking code goes here
//**************************
//if there is any cheating flash master LED
if (flashFlag == true)
{
if (millis() - masterMillis >= 250)
{
masterMillis = millis();
//toggle master LED
digitalWrite(masClickLED, !digitalRead(masClickLED));
}
}
//**************************
//are we in the 5 second timeout period?
if (FiveSecFlag == true && millis() - winnerMillis > 100ul)
{
//flash winners LED
winnerMillis = millis();
//toggle LED
digitalWrite(chiClickLED[winnerIndex], !digitalRead(chiClickLED[winnerIndex]));
}
else if (FiveSecFlag == true && millis() - FiveSecMillis >= onTime)
{
//five seconds has gone by, disable timeout
FiveSecFlag = false;
//turn off contestant LEDs
for (int i = 0; i < pinCount; i++)
{
digitalWrite (chiClickLED[i], LEDoff) ;
}
//turn off master LED
digitalWrite (masClickLED, LEDoff);
//allow cheat checking
cheatFlag = true;
}
//**************************
//time to scan the switches?
if (millis() - debounceMillis >= debounceDelay)
{
debounceMillis = millis();
readSwitches();
}
} // END of l o o p ( )
//*********************************************************
void readSwitches()
{
//**************************
//should we check for cheating?
if (cheatFlag == true)
{
//check to see if any number of contestants are holding their switch down
for (int i = 0; i < pinCount; i++)
{
if (digitalRead(chiClick[i]) == pushed)
{
//turn on the cheaters LED
digitalWrite (chiClickLED[i], LEDon);
//notify master that a switch is being pressed too early
flashFlag = true;
}
}
}
//**************************
//if there is cheating, has the master acknowledged it
if (flashFlag == true && digitalRead(masClick) == pushed)
{
//Stop master LED flashing
flashFlag = false;
//turn off Master LED
digitalWrite (masClickLED, LEDoff);
//turn off all contestant LEDs
for (int i = 0; i < pinCount; i++)
{
digitalWrite (chiClickLED[i], LEDoff) ;
}
//must give some time after cheat acknowledgment
delayMillis = millis();
}
//**************************
//Start the game?
//not in 5 second mode, no cheating, we are not currently poling, 2 seconds has gone by since
//the last cheat acknowledgment and the master switch is now pressed
if (FiveSecFlag == false && flashFlag == false && polingFlag == false && millis() - delayMillis > 2000
&& digitalRead(masClick) == pushed)
{
//turn on master LED
digitalWrite (masClickLED, LEDon);
//allow scanning
polingFlag = true;
//disable check checking
cheatFlag = false;
}
//**************************
//should we scan for a winner?
if (polingFlag == true)
{
//scan for the first LOW switch
for (int i = 0; i < pinCount; i++)
{
if (digitalRead(chiClick[i]) == pushed)
{
//save the winners array index
winnerIndex = i;
winnerMillis = millis();
//turn on the winner LED
digitalWrite (chiClickLED[i], LEDon);
//disable further scanning
polingFlag = false;
//Enable the 5 second countdown timer
FiveSecFlag = true;
FiveSecMillis = millis();
//we found the winner, stop looking any further
break;
}
}
}
} // END of r e a d S w i t c h e s ( )
//*********************************************************