Arduino code for the Clap-Activated Applause Machine https://hackaday.io/project/166959-clap-activated-applause-machine

clapper.ino

//***************************************************************************************
// Clap-Activated Applause Machine
//
// By: Dillon Nichols
// @Dillon1337
// https://hackaday.io/project/166959-clap-activated-applause-machine
//
// This work is licensed under a Creative Commons Attribution 3.0 Unported License.
//***************************************************************************************

// pin definitions
const int motor = 9;
const int button = 7;
const int mic = 3;
const int led = A3;

// delay after an interrupt is triggered
const int debounceDelay = 50;

// counter for time between claps
int ms_ellapsed = 0;

// disable the microphone interrupts while clapping
bool interruptEnabled = false;

// when the first clap is detected
bool firstDetected = false;

// when the second clap is detected
bool startClapping = false;

// a reasonable time between claps (as compared to a human)
#define CLAP_DELAY 286

// SUPER SECRET ALGORITHIM
// (just clap a bunch of times)
void clapAlgorithim(void) {
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  clapWithDelay(CLAP_DELAY);
  
  // extra code to fake turning itself off
  /*delay(1000);
  clapWithDelay(150);
  clapWithDelay(150);
  */
}

// interrupt triggers this function
void soundDetected(void) {
  // only run if interrupt is enabled
  if(interruptEnabled) {
    // on first clap detection
    if(firstDetected == false) {
      firstDetected = true;
      // start the counter at the debounce delay value
      // because we waited that long earlier without counting
      ms_ellapsed = debounceDelay;
      //Serial.println("1st sound detected");
    }
    // second clap detected
    else {
      //Serial.print("2nd sound detected at ");
      //Serial.println(ms_ellapsed);

      // 2 claps with 0.2 to 1 second in between triggers the machine
      if(ms_ellapsed > 200 && ms_ellapsed < 1000) {
        startClapping = true;
      }

      // reset variables
      ms_ellapsed = 0;
      firstDetected = false;
    }

    // disable the interrupt for a bit (debouncing)
    interruptEnabled = false;
  }
}

void setup() {
  // make the mic an input and trigger a function if the pin rises
  pinMode(mic, INPUT);
  attachInterrupt(digitalPinToInterrupt(mic), soundDetected, RISING);
  interruptEnabled = true;

  // enable all Serial lines for debugging
  //Serial.begin(115200);

  // configure other pins
  pinMode(led, OUTPUT);
  pinMode(motor, OUTPUT);
  pinMode(button, INPUT);
}

// clap by spinning the motor one revolution and then waiting
void clapWithDelay(int waitTime) {
  // spin the motor until button is pressed
  while(digitalRead(button) == LOW)
  {
    digitalWrite(motor, HIGH);
  }
  // then turn off motor
  digitalWrite(motor, LOW);

  // wait some time
  delay(waitTime);
}

void loop() {
  // loop once per millisecond
  delay(1);

  // count up the timer between claps
  if(firstDetected){
    ms_ellapsed++;
  }
  
  // after 2.5 seconds between claps, reset the timer (timeout)
  if (ms_ellapsed > 2500) {
    ms_ellapsed = 0;
    firstDetected = false;
    //Serial.println("Timeout.. resetting..");
  }
  
  // mic input debouncing
  // wait some time after disabling the interrupt to enable it again
  if (interruptEnabled == false) {
    //Serial.println("Interrupt disabled.. waiting..");
    delay(debounceDelay);
    interruptEnabled = true;
  }

  // when it is time to clap..
  if(startClapping) {
    // turn on the applause light
    digitalWrite(led, HIGH);
    // start clapping
    clapAlgorithim();
    // turn off the light
    digitalWrite(led, LOW);
    startClapping = false;
  }
}