Arduino Halloween Project 2022

The Code:

// Include Libraries
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h> 

// Define Temp Sensor
#define DHTType DHT11
#define tempPin 2
DHT HT(tempPin, DHTType);

//Define OLED Settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

//Declare Potentiometer To Control Detection Sensitivity
int potPin = A0; // Analog input pin for the potentiometer
float ALERT_THRESHOLD = 0.01;   // Variable to store the threshold value
float thresholdPotValue;   // Variable to store the potentiometer reading

float currentTemp;
float previousTemp = 0.0;
int ledPin = 10;
int buzzerPin = 12;

void setup() {
  pinMode(ledPin,OUTPUT);
  pinMode(buzzerPin,OUTPUT);
  Serial.begin(9600);
  HT.begin();
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display(); //Display logo
  delay(1000); 
  display.clearDisplay();
}

void loop() {
  // Read the potentiometer value
  thresholdPotValue = analogRead(potPin);
  
  // Map the potentiometer value to your temperature range (e.g., 0.01 to 2.0 degrees Celsius)
  ALERT_THRESHOLD = map(thresholdPotValue, 0, 1023, 1, 100) / 100.0; // Adjust the mapping as needed and convert to float
  Serial.println(ALERT_THRESHOLD);
  
  // Read Temp Sensor
  currentTemp = HT.readTemperature();
  Serial.println(currentTemp);

  // Display Temp on OLED
  oledDisplay();
  
  // Check if the temperature has dropped below the threshold
  if ((previousTemp - currentTemp) >= ALERT_THRESHOLD) {
    
    // Temperature has dropped suddenly; trigger an alert
    Serial.println("Temperature has dropped suddenly!");
    
    // LED and buzzer alerts
    for (int i = 0; i < 2; i++) { // Flash the LED 5 times
      digitalWrite(buzzerPin, HIGH); // Turn the LED on
      delay(200); // Delay for 200 milliseconds (adjust as needed)
      digitalWrite(buzzerPin, LOW);  // Turn the LED off
      delay(200); // Delay for 200 milliseconds
      for (int i = 0; i < 3; i++) { // Sound the buzzer 3 times
        digitalWrite(ledPin, HIGH); // Turn the buzzer on
        delay(500); // Delay for 500 milliseconds (adjust as needed)
        digitalWrite(ledPin, LOW);  // Turn the buzzer off
        delay(500); // Delay for 500 milliseconds
      }
    }  
  }  
  previousTemp = currentTemp; 
  delay(1000); 
}

// OLED display function
void oledDisplay() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(40, 0);
  display.print("Temp");
  display.setCursor(38, 40);
  display.print(currentTemp);
  display.display();
}