An better version of the Arduino random smoke generator

microfogger-random-smoke-better

#define SMOKE_PIN A0
#define MIN_TIME 1000
#define MAX_TIME 5000

bool isSmoking = false;
int timerDuration = 0;
unsigned long startTime;

void setup() {
  // configure the output pin to control the smoke generator
  pinMode(SMOKE_PIN, OUTPUT);
  // Enable the Arduino device's onboard LED
  pinMode(LED_BUILTIN, OUTPUT);
  // start making smoke. You can do this later based
  // on some other trigger if you want
  startSmoke();
}

void loop() {
  // ===
  // do some stuff
  // ===
  checkSmokeTimer();
  // ===
  // do some other stuff
  // ===
}

void startSmoke() {
  // turn the smoke machine on
  digitalWrite(SMOKE_PIN, HIGH);
  digitalWrite(LED_BUILTIN, HIGH);
  isSmoking = true;
  startTime = millis();  // capture when we started the timer
  // figure out how long it generates smoke (randomly)
  timerDuration = (int)random(MIN_TIME, MAX_TIME);  // milliseconds
}

void startDelay() {
  // turn the smoke machine off, then wait a while
  digitalWrite(SMOKE_PIN, LOW);
  digitalWrite(LED_BUILTIN, LOW);
  isSmoking = false;
  startTime = millis();  // capture when we started the timer
  // figure out how long it waits between generating smoke (random duration)
  timerDuration = (int)random(MIN_TIME, MAX_TIME);  // milliseconds
}

void checkSmokeTimer() {
  // Set `timerDuration` to 0 to stop this process (no smoke)
  if (timerDuration > 0) {
    // check to see if enough time's passed since the timer started
    if ((millis() - startTime) > timerDuration) {
      // timer expired, so time to switch modes
      if (!isSmoking) {
        // we're not smoking, so start the smoke
        startSmoke();
      } else {
        // we're smoking, so switch to delay
        startDelay();
      }
    }
  }
}