🛠️ IoT Projects – Complete Guide

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>
#include <Adafruit_BMP280.h>

#define DHTPIN 4
#define DHTTYPE DHT22
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

DHT dht(DHTPIN, DHTTYPE);
Adafruit_BMP280 bmp;
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);
  dht.begin();
  bmp.begin(0x76);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
}

void loop() {
  float temp = dht.readTemperature();
  float hum  = dht.readHumidity();
  float pres = bmp.readPressure() / 100.0F;

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);

  display.setCursor(0, 0);
  display.print("Temp: ");
  display.print(temp);
  display.println(" C");

  display.print("Humidity: ");
  display.print(hum);
  display.println(" %");

  display.print("Pressure: ");
  display.print(pres);
  display.println(" hPa");

  display.display();
  delay(2000);
}

#define TRIG 5
#define ECHO 18
#define IN1  25
#define IN2  26
#define IN3  27
#define IN4  32

void setup() {
  Serial.begin(115200);
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(IN1, OUTPUT); pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT); pinMode(IN4, OUTPUT);
}

long getDistance() {
  digitalWrite(TRIG, LOW);  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH); delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  long dur = pulseIn(ECHO, HIGH);
  return dur * 0.034 / 2;
}

void moveForward()  { digitalWrite(IN1,HIGH); digitalWrite(IN2,LOW);
                       digitalWrite(IN3,HIGH); digitalWrite(IN4,LOW); }
void turnRight()    { digitalWrite(IN1,HIGH); digitalWrite(IN2,LOW);
                       digitalWrite(IN3,LOW);  digitalWrite(IN4,HIGH); }
void stopMotors()   { digitalWrite(IN1,LOW); digitalWrite(IN2,LOW);
                       digitalWrite(IN3,LOW); digitalWrite(IN4,LOW); }

void loop() {
  long dist = getDistance();
  Serial.print("Distance: "); Serial.print(dist); Serial.println(" cm");

  if (dist < 20) {
    stopMotors();  delay(300);
    turnRight();  delay(400);
  } else {
    moveForward();
  }
  delay(100);
}

#define SOUND_PIN 27
#define LED_PIN   2
bool ledState = false;

void setup() {
  Serial.begin(115200);
  pinMode(SOUND_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  int soundVal = digitalRead(SOUND_PIN);

  if (soundVal == HIGH) {
    ledState = !ledState;
    digitalWrite(LED_PIN, ledState);
    Serial.println(ledState ? "CLAP → LED ON" : "CLAP → LED OFF");
    delay(300); // Debounce
  }
}

#define TRIG 5
#define ECHO 18
#define BUZZ 19
#define GREEN  25
#define YELLOW 26
#define RED    27

void setup() {
  Serial.begin(115200);
  pinMode(TRIG, OUTPUT); pinMode(ECHO, INPUT);
  pinMode(BUZZ, OUTPUT);
  pinMode(GREEN, OUTPUT); pinMode(YELLOW, OUTPUT); pinMode(RED, OUTPUT);
}

long getDistance() {
  digitalWrite(TRIG, LOW);  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH); delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  return pulseIn(ECHO, HIGH) * 0.034 / 2;
}

void loop() {
  long dist = getDistance();
  Serial.print("Water distance: "); Serial.print(dist); Serial.println(" cm");

  // Reset all
  digitalWrite(GREEN, LOW); digitalWrite(YELLOW, LOW);
  digitalWrite(RED, LOW);   digitalWrite(BUZZ, LOW);

  if (dist > 20) {
    digitalWrite(GREEN, HIGH); // Low level
  } else if (dist > 8) {
    digitalWrite(YELLOW, HIGH); // Medium
  } else {
    digitalWrite(RED, HIGH);  // Overflow!
    digitalWrite(BUZZ, HIGH);
    Serial.println("⚠ TANK OVERFLOW WARNING!");
  }
  delay(1000);
}