An Arduino project that my son and I collaborated on.

burster_buster.ino

/*
 * wot
 *  water level & low temp alert
 *  
 * status
 *  water level sensor 
 *    https://www.fasttech.com/p/3809800
 *    works
 *  active buzzer 
 *    https://www.fasttech.com/p/1219302
 *    just clicks (wired incorrectly?)
 *  temp module
 *    https://www.fasttech.com/p/1012005
 *    not started
 * 
 * inspired by
 *   https://www.youtube.com/watch?v=3Qvdl0q9soE (sensor values)
 *   and 
 *   https://tkkrlab.nl/wiki/Arduino_KY-012_Active_buzzer_module (wiring the buzzer)
 *   and
 *   http://www.mauroalfieri.it/elettronica/funduino-water-sensor-test.html ()
 */

// temp sensor setup
#include <dht.h>
dht DHT;
#define DHT11_PIN 7
int minimumTemperature = 50;
int theTemperature = 65;

const int analogInPin = A0; 
const int analogOutPin = 9; 

int sensorValue = 0;        
int outputValue = 0;        
int minimumSensorValue = 200;
int minimumOutputValue = 50;

int speakerPin = 8;

bool detectsWater = false;

int debugToConsole = true;

// this function is called once at the beginning
void setup() {  

  if(debugToConsole){
    Serial.println("");  
    Serial.println("* * * * * setup() * * * * *");  
  }
  
  // setup speaker
  pinMode (speakerPin, OUTPUT);

  // setup dht
  // n/a

  // setup output
  if(debugToConsole){
    Serial.begin(9600);  
  }
}

// this function is called over and over again
void loop() {

  if(debugToConsole){
    Serial.println("");  
    Serial.println("* * * * * loop() * * * * *");  
  }

  // get the temp
  theTemperature = getTemperature();

  // check to see if water is detected
  detectsWater = getDetectsWater();

  // if detects water OR the temp is less than the min temp, call the doAlert function
  if(detectsWater || theTemperature < minimumTemperature){
    doAlert();

  // otherwise insert a brief pause
  }else{
    delay(1000); 
  }

  // go around the loop again
}

int getTemperature(){
  int chk = DHT.read11(DHT11_PIN);
  int temperatureCelcius;
  int temperatureFareinheit;
  
  delay(50);

  temperatureCelcius = DHT.temperature;
  temperatureFareinheit = (temperatureCelcius*1.8)+32;

  if(debugToConsole){
    Serial.print("getTemperature(), temperatureFareinheit = ");
    Serial.println(temperatureFareinheit);
  }

  return temperatureFareinheit;
}

bool getDetectsWater(){

  bool waterDetected = false;
  
  sensorValue = analogRead(analogInPin);
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  analogWrite(analogOutPin, outputValue);

  if(sensorValue > minimumSensorValue && outputValue > minimumOutputValue){
    waterDetected = true;
  }

  if(debugToConsole){
    /*
    Serial.print("getDetectsWater(), sensor = ");
    Serial.print(sensorValue);
    Serial.print(" and output = ");
    Serial.println(outputValue);
    */
    Serial.print("getDetectsWater(), waterDetected = ");
    Serial.print(waterDetected);
  }

  return waterDetected;
}

void doAlert(){
  // writeAlert();
  // sendAlert();
  playAlarm(); 
}

void playAlarm(){
  if(debugToConsole){
    Serial.println("playAlarm() !!!");
  }
  analogWrite(speakerPin, 255);
  delay(50);
  analogWrite(speakerPin, 100);
  delay(50);
  analogWrite(speakerPin, 0);
  delay(10);

}