ESP8266 + DHT11/22 + Photoresistor

Team weilovka: Martin Václavík, Michal Joska, jarda123

Published November 23, 2019

Air Quality of Office Rooms Application

Measuring quality of air to improve quality of work, improving mental health of employees.

IntermediateWork in progress1,284

Things used in this project

Hardware components

Breadboard (generic)

Arduino UNO

HARDWARIO Core Module

HARDWARIO CO2 Module

Micro-USB to USB Cable (Generic)

Jumper wires (generic)

Capacitor 470 µF

HARDWARIO Climate Module

HARDWARIO Radio Dongle

Raspberry Pi 3 Model B+

Resistor 10k ohm

Espressif ESP8266 ESP-01

DHT22 Temperature Sensor

Photo resistor

USB-A to Mini-USB Cable

Story

We are making application with our hardware device that will show you quality of air in your area. This device could be used as one single unit, for example in small home office, or maybe in large companies with multiple devices. This device is able to read humidity, temperature, amount of CO2 in air etc.

We made it because in better quality of air you are more productive and it is more healthier.

1) First we need to connect CO2 module, core module and climate module together like on this photo:

2) Then we connect it to Raspberry pi with radio dongle + output

Type IP of rasberry to browser (for example: 10.10.1.11.22 )

You will have to press button start pairing and button on Raberry pi untill it appears like this:

Then you type code like this in function folder

ESP8266 + DHT11/22 + Photoresistor

We use ESP8266 for connecting to WiFi and send the temperature and humidity to Firebase.

1) Download Arduino IDE from official sites.

We use latest version - 1.8.10

https://www.arduino.cc/en/Main/Software

2) Create new project

In Arduino IDE click on File -> New

3) Download required libraries for our project

For ESP8266 Wifi:

Copy this link to board manager:

https://arduino.esp8266.com/stable/package_esp8266com_index.json

In File -> Preferences -> Additional Boards Manager URLs: -> Paste in the box link -> And click Ok

Now go to Tools -> Board:"Arduino/Genuino Uno" -> Boards Manager -> In top right search bar type ESP8266 and select latest version and click Install. Now you have library for ESP8266 WiFi.

For DHT11/22

Download library from github.com/adafruit/DHT-sensor-library -> Go to Arduino IDE -> Select Sketch -> Include library -> Add .ZIP library -> Select downloaded library and select Open -> Now you jave installed library for DHT sensor.

For Firebase

Donwnoad library from https://github.com/FirebaseExtended/firebase-arduino -> And repeat the same action as with the previous library.

4) Include libraries

We include libraries, because we use component that aren't included in default Arduino IDE.

5) Define DHT sensor

In this step, we define DHT sensor 11 or 22, and Pin where we connect DHT11/22 to ESP8266

6) Declaring variables

We declarate 2 variables for temperature and humidity.

7) Defining WiFi SSID and Password

In SSID write your WiFi name, and define password.

8) Start your serial monitor

This command we type in void setup() {}

9) Establishing connection to network

10) Start measuring of DHT and Firebase

11) Now, let's roll to DHT sensor

For temperature we use dht.readTemperature() and for humidity dht.readHumidity()

But, if the sensors sending wrong data, for that problem there is IF condition and type "Failed to read from DHT sensor!"

12) Getting values from photoresistor

First command declaring sensorValue where we get values from Analog input. In next step we dividing 1023(scale of number of bits) by 3.3(voltage on DHT photoresistor) on Arduino Uno it can be 5V.

13)Sending data to Firebase

Start typing with Firebase and pushFloat, we use float to get decimal number and pushing values to our database. In scopes, we saying where on Firebase will be saved, and typing the variables to be printed on web.

Code

#include <ESP8266WiFi.h>        // Include the Wi-Fi library
#include <DHT.h>
#include <FirebaseArduino.h>

#define FIREBASE_AUTH "Zojx6nlQZPsrHmJ9O51hojJnI25r3zEjpVhrctNJ"
#define FIREBASE_HOST "airq-e073b.firebaseio.com"


#define DHTTYPE DHT22
#define DHTPIN D1

DHT dht(DHTPIN, DHTTYPE);
float temperature;
float humidity;



const char* ssid     = "ssid";         // The SSID (name) of the Wi-Fi network you want to connect to
const char* password = "password";     // The password of the Wi-Fi network

void setup() {
  Serial.begin(115200);         // Start the Serial communication to send messages to the computer
  delay(10);
  Serial.println('\n');
  
  WiFi.begin(ssid, password);      // Connect to the network
  Serial.print("Connecting to ");
  Serial.print(ssid); Serial.println(" ...");

  int i = 0;
  while (WiFi.status() != WL_CONNECTED) {    // Wait for the Wi-Fi to connect
    delay(1000);
    Serial.print(++i); Serial.print(' ');
  }

  Serial.println('\n');
  Serial.println("Connection established!");  
  Serial.print("IP address:\t");
  Serial.println(WiFi.localIP());         // Send the IP address of the ESP8266 to the computer

  dht.begin();
  Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH); 
}

void loop() 
{
  temperature = dht.readTemperature();
  humidity = dht.readHumidity();
  if (isnan(humidity) || isnan(temperature)) {      // Check if any reads failed and exit early (to try again).
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }

  int sensorValue = analogRead(A0);
  float voltage = sensorValue * (3.3 / 1023.0);

  
  Serial.println(temperature);
  Serial.println(humidity);
  Serial.println(voltage);

  delay(4000);
  
  Firebase.pushFloat("/DHT11_2/Humidity", humidity);         //setup path and send readings
  Firebase.pushFloat("/DHT11_2/Temperature", temperature);   //setup path and send readings
  Firebase.pushFloat("/Photoresistor_2/Value", voltage);
  



  
}

Air Quality of Office Rooms Application

Things used in this project

Hardware components

Story

ESP8266 + DHT11/22 + Photoresistor

Code

Code

Credits

Martin Václavík

Michal Joska

jarda123

Comments

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Air Quality of Office Rooms Application

Air Quality of Office Rooms Application

Things used in this project

Hardware components

Story

ESP8266 + DHT11/22 + Photoresistor

Code

Code

Credits

Martin Václavík

Michal Joska

jarda123

Comments

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