IoT Sensor Systems —
পড়ো তোমার চারপাশ

// ══ Jontro-Tantrik Lab | IoT Sensor Series ══
// Tutorial: DHT11 Temperature & Humidity Reading

#include <DHT.h>

#define DHT_PIN   2        // DATA পিন
#define DHT_TYPE  DHT11    // সেন্সরের মডেল

DHT dht(DHT_PIN, DHT_TYPE);

void setup() {
  Serial.begin(9600);
  dht.begin();
  Serial.println("=== DHT11 Ready ===");
}

void loop() {
  delay(2000);  // DHT11-এর জন্য ২ সেকেন্ড বিরতি জরুরি

  float humidity    = dht.readHumidity();
  float temperature = dht.readTemperature(); // ডিফল্ট সেলসিয়াস

  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("ERROR: Sensor read failed!");
    return;
  }

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" C");

  Serial.print("Humidity:    ");
  Serial.print(humidity);
  Serial.println(" %");
  Serial.println("--------------------");
}

// ══ Jontro-Tantrik Lab | LDR Auto Night Mode ══

#define LDR_PIN    A0   // এনালগ পিন
#define LED_PIN    13   // বিল্ট-ইন LED
#define THRESHOLD  400  // ৪০০-এর নিচে = অন্ধকার

void setup() {
  Serial.begin(9600);
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  int lightVal = analogRead(LDR_PIN);

  Serial.print("Light Level: ");
  Serial.println(lightVal);

  if (lightVal < THRESHOLD) {
    digitalWrite(LED_PIN, HIGH); // অন্ধকারে LED জ্বালাও
    Serial.println(">> Night Mode: ON");
  } else {
    digitalWrite(LED_PIN, LOW);  // আলোয় LED নেভাও
    Serial.println(">> Day Mode: OFF");
  }

  delay(500);
}

// ══ Jontro-Tantrik Lab | HC-SR04 Distance Sensor ══

#define TRIG_PIN  9
#define ECHO_PIN  10

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

long getDistance() {
  // TRIG পিনে ১০ মাইক্রোসেকেন্ডের pulse পাঠাও
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // ECHO পিনে pulse-এর সময় মাপো (microseconds)
  long duration = pulseIn(ECHO_PIN, HIGH);

  // দূরত্ব: (সময় × ০.০৩৪) / ২ = সেন্টিমিটার
  return (duration * 0.034) / 2;
}

void loop() {
  long dist = getDistance();

  Serial.print("Distance: ");
  Serial.print(dist);
  Serial.println(" cm");

  if (dist < 20) {
    Serial.println(">> ALERT: Object too close!");
  }

  delay(200);
}

// ══ Jontro-Tantrik Lab | Smart Room Monitor ══
// Sensors: DHT11 + LDR + HC-SR04

#include <DHT.h>

#define DHT_PIN   2
#define DHT_TYPE  DHT11
#define LDR_PIN   A0
#define TRIG_PIN  9
#define ECHO_PIN  10

DHT dht(DHT_PIN, DHT_TYPE);

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

void setup() {
  Serial.begin(9600);
  dht.begin();
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.println("=== Smart Room Monitor v1.0 ===");
}

void loop() {
  delay(2000);

  float temp  = dht.readTemperature();
  float hum   = dht.readHumidity();
  int   light = analogRead(LDR_PIN);
  long  dist  = getDistance();

  Serial.println("+--------------------------+");
  Serial.print("| Temp:     "); Serial.print(temp);  Serial.println(" C");
  Serial.print("| Humidity: "); Serial.print(hum);   Serial.println(" %");
  Serial.print("| Light:    "); Serial.println(light);
  Serial.print("| Distance: "); Serial.print(dist); Serial.println(" cm");

  // স্বয়ংক্রিয় সতর্কতা
  if (temp > 35.0)  Serial.println("| [!] HIGH TEMPERATURE!");
  if (hum  > 80.0)  Serial.println("| [!] HIGH HUMIDITY!");
  if (dist < 15)    Serial.println("| [!] OBJECT DETECTED!");
  Serial.println("+--------------------------+");
}