#include <Wire.
h>
#include <LiquidCrystal_I2C.h>
#include "Adafruit_SHT4x.h"
// Define pins
const int relay_pin = A1;
const int buzzer_pin = A2;
// Initialize SHT41 sensor
Adafruit_SHT4x sht4x = Adafruit_SHT4x();
// Define LCD parameters
LiquidCrystal_I2C lcd(0x27, 16, 2);
// Non-blocking timer variables for sensor
unsigned long previousSensorMillis = 0;
const long sensorInterval = 1000; // SHT41 can be read more frequently, 1
second is fine
// Non-blocking timer variables for buzzer
unsigned long previousBuzzerMillis = 0;
const long buzzerOnDuration = 100; // Time the buzzer is ON (e.g., 100ms)
const long buzzerOffDuration = 3000; // Time the buzzer is OFF (3 seconds)
// Non-blocking timer variables for "FANMATIC" text
unsigned long previousTextMillis = 0;
const long textInterval = 30000; // 30 seconds
// Sensor data variables
float humidity = 0.0;
float temperature = 0.0;
// State variable for buzzer
bool buzzerState = LOW; // Tracks the current state of the buzzer
void setup() {
Serial.begin(9600);
Wire.begin();
lcd.init();
lcd.backlight();
// SHT41 sensor initialization
if (! sht4x.begin()) {
Serial.println("Couldn't find SHT4x");
while (1) delay(1);
Serial.println("Found SHT4x sensor");
pinMode(relay_pin, OUTPUT);
pinMode(buzzer_pin, OUTPUT);
// Initial read to populate values from SHT41
sensors_event_t humidity_event, temp_event;
sht4x.getEvent(&humidity_event, &temp_event);
if (!isnan(temp_event.temperature) && !
isnan(humidity_event.relative_humidity)) {
temperature = temp_event.temperature;
humidity = humidity_event.relative_humidity;
void loop() {
unsigned long currentMillis = millis();
// Sensor reading logic (runs every 1 second)
if (currentMillis - previousSensorMillis >= sensorInterval) {
previousSensorMillis = currentMillis;
sensors_event_t humidity_event, temp_event;
sht4x.getEvent(&humidity_event, &temp_event);
if (!isnan(temp_event.temperature) && !
isnan(humidity_event.relative_humidity)) {
temperature = temp_event.temperature;
humidity = humidity_event.relative_humidity;
Serial.print("Temp: ");
Serial.print(temperature);
Serial.print(" °C");
Serial.print(" Hum: ");
Serial.print(humidity);
Serial.println(" %");
// "FANMATIC" text display logic (runs every 30 seconds)
if (currentMillis - previousTextMillis >= textInterval) {
previousTextMillis = currentMillis;
// Display "FANMATIC" and then clear after a short delay to be seen
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("FANMATIC");
delay(3000); // Wait for 3 seconds to make the text visible
lcd.clear(); // Clear the screen before the main display loop resumes
// Main LCD display logic (runs continuously unless interrupted by
FANMATIC)
lcd.setCursor(0, 0);
lcd.print("Hum: ");
lcd.print(humidity);
lcd.print(" %");
lcd.setCursor(0, 1);
lcd.print("Temp: ");
lcd.print(temperature);
lcd.print("`C");
// Control buzzer and relay based on humidity OR temperature
if (humidity > 60.0 || temperature > 25.0) {
digitalWrite(relay_pin, LOW);
// Buzzer blinking logic (runs continuously while relay is OFF)
if (buzzerState == LOW && (currentMillis - previousBuzzerMillis >=
buzzerOffDuration)) {
digitalWrite(buzzer_pin, HIGH);
previousBuzzerMillis = currentMillis;
buzzerState = HIGH;
} else if (buzzerState == HIGH && (currentMillis - previousBuzzerMillis >=
buzzerOnDuration)) {
digitalWrite(buzzer_pin, LOW);
previousBuzzerMillis = currentMillis;
buzzerState = LOW;
} else {
// If conditions are not met, ensure both are off
digitalWrite(buzzer_pin, LOW);
digitalWrite(relay_pin, HIGH);
}
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
// Define pins
const int relay_pin = A1;
const int buzzer_pin = A2;
const int DHTPIN = 2; // Pin where the DHT sensor is connected
const int DHTTYPE = DHT11; // Can be DHT11 or DHT22
// Initialize DHT sensor
DHT dht(DHTPIN, DHTTYPE);
// Define LCD parameters
LiquidCrystal_I2C lcd(0x27, 16, 2);
// Non-blocking timer variables for sensor
unsigned long previousSensorMillis = 0;
const long sensorInterval = 2000; // DHT sensors require a 2-second interval
// Non-blocking timer variables for buzzer
unsigned long previousBuzzerMillis = 0;
const long buzzerOnDuration = 100; // Time the buzzer is ON (e.g., 100ms)
const long buzzerOffDuration = 3000; // Time the buzzer is OFF (3 seconds)
// Non-blocking timer variables for "FANMATIC" text
unsigned long previousTextMillis = 0;
const long textInterval = 30000; // 30 seconds
// Sensor data variables
float humidity = 0.0;
float temperature = 0.0;
// State variable for buzzer
bool buzzerState = LOW; // Tracks the current state of the buzzer
void setup() {
Serial.begin(9600);
Wire.begin();
lcd.init();
lcd.backlight();
dht.begin();
pinMode(relay_pin, OUTPUT);
pinMode(buzzer_pin, OUTPUT);
// Initial read to populate values
humidity = dht.readHumidity();
temperature = dht.readTemperature();
void loop() {
unsigned long currentMillis = millis();
// Sensor reading logic (runs every 2 seconds)
if (currentMillis - previousSensorMillis >= sensorInterval) {
previousSensorMillis = currentMillis;
float newHumidity = dht.readHumidity();
float newTemperature = dht.readTemperature();
if (!isnan(newHumidity) && !isnan(newTemperature)) {
humidity = newHumidity;
temperature = newTemperature;
Serial.print("Temp: ");
Serial.print(temperature);
Serial.print(" °C");
Serial.print(" Hum: ");
Serial.print(humidity);
Serial.println(" %");
// "FANMATIC" text display logic (runs every 30 seconds)
if (currentMillis - previousTextMillis >= textInterval) {
previousTextMillis = currentMillis;
// Display "FANMATIC" and then clear after a short delay to be seen
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("FANMATIC");
delay(3000); // Wait for 3 seconds to make the text visible
lcd.clear(); // Clear the screen before the main display loop resumes
// Main LCD display logic (runs continuously unless interrupted by
FANMATIC)
lcd.setCursor(0, 0);
lcd.print("Hum: ");
lcd.print(humidity);
lcd.print(" %");
lcd.setCursor(0, 1);
lcd.print("Temp: ");
lcd.print(temperature);
lcd.print("`C");
// Control buzzer and relay based on humidity OR temperature
if (humidity > 60.0 || temperature > 25.0) {
digitalWrite(relay_pin, LOW);
// Buzzer blinking logic (runs continuously while relay is OFF)
if (buzzerState == LOW && (currentMillis - previousBuzzerMillis >=
buzzerOffDuration)) {
digitalWrite(buzzer_pin, HIGH);
previousBuzzerMillis = currentMillis;
buzzerState = HIGH;
} else if (buzzerState == HIGH && (currentMillis - previousBuzzerMillis >=
buzzerOnDuration)) {
digitalWrite(buzzer_pin, LOW);
previousBuzzerMillis = currentMillis;
buzzerState = LOW;
} else {
// If conditions are not met, ensure both are off
digitalWrite(buzzer_pin, LOW);
digitalWrite(relay_pin, HIGH);
Final
