Introduction: Simple DHT11 Temperature Moniter

About: Master in Electronics Engineering

The project is about Temperature logger system. In this project you can monitor your room temperature on your android smartphone app. It is simple to make and accurate. This project shows temperature, humidity and heat index. It is very simple to make and components are not costly.

Step 1: Components:

1. Arduino Uno or Any

2. DHT11/22

3. Breadboard

4. Resistor 1K x1

5. Bluetooth Hc-05 or Hc-06

7. Patch Cords

8. Battery

9. Android Smartphone

10. Little Knowledge about Arduino

Step 2: Connections:

First Upload sketch from next step to arduino then make connections.

Connect pin 2 of arduino to dht11 pin 2 as shown in ckt diagram.

5volt of arduino to Vcc of dht11 and bluetooth.

Gnd of arduino to Gnd of dht11 & bluetooth.

Tx of the arduino to Rx of Bluetooth .

Connect resisstor 1k ohm between pin 1 & 2 of DHT11 sensor.

Step 3: Upload Sketch:

First Include dht11 library to your arduino ide

Go to>sketch>inclued library>Add zip> select the zip file

Now upload sketch

#include "DHT.h"

#define DHTPIN 2 // pin for connecting dht11/dht22 sensor

#define DHTTYPE DHT11 // DHT 11 : type of sensor you are using


void setup()

{ Serial.begin(9600);

Serial.println("DHT11 Moniter System");



void loop()

{ delay(2000);// Wait a few seconds for sensor to measure

float h = dht.readHumidity();

// Read temperature as Celsius

float t = dht.readTemperature();

// Read temperature as Fahrenheit

float f = dht.readTemperature(true);

// Check if any reads failed and exit early (to try again).

if (isnan(h) || isnan(t) || isnan(f))

{ Serial.println("Failed to read from DHT sensor!");



float hi = dht.computeHeatIndex(f, h); //compute the heat index, must give temp in fahrenheit

Serial.print("Humidity: ");


Serial.print(" %\n\n");

Serial.print("Temperature: ");


Serial.print(" *C \n");


Serial.print(" *F\n");

Serial.print("Heat index: ");


Serial.println(" *F");


Step 4: Installing Android App

You Can also build your own App using MIT Appinventor 2.

Step 5:

Start Bluetooth Of phone Pair with Hc-05 default password is 1234 or 12345

Now open App Select Bluetooth Device Hc-05.

And Moniter the Temperature, Humidity & Heat Index.