ESP8266 IoT Platform using Firebase

This is an easy way to do real-time monitoring with the DHT22/DHT11.

BeginnerFull instructions provided3,776

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

This is for our WiFi

Adafruit DHT22 temperature-humidity sensor

Temperature and humidity

High Brightness LED, White

This is what we can control in the app

Jumper wires (generic)

Connect Components

Breadboard (generic)

Organize Components

Software apps and online services

Arduino IDE

Program ESP8266

Google Firebase

Database

MIT App Inventor 2

App

Story

Videos:

Here are my videos on getting this set up:

Part 1

Part 2

Part 3

Part 4

Part 5

Part 2.1

Part 2.2

Note that I am new to Firebase so they might be internal errors in the app. Tell me if you spot any.

Testing DHT22

Run code and build circuit:

Circuit

//Code
#include "DHT.h"
#define DHTPIN 6
DHT dht;
#define DHTTYPE DHT22     //Change this to any type of DHT Sensor you're Using!
DHT(DHTPIN, DHTTYPE);
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);                               //Starts serial
delay(5000);                                      //Waits before reading from sensor
Serial.println("DHT22 Temp. And Humi. Test");     //Prints the intro
}
void loop() {
// put your main code here, to run repeatedly:
dht.read11(DHTPIN);                             //Reads from the sensor
Serial.println("Humi. ---------- ");            //Prints humidity
Serial.print(DHT.humidity);                       //Prints humidity
Serial.print("%         ");                     //Marks the humidity as %
Serial.print("Temp. ------------ ");            //Prints temperature           
Serial.print(DHT.temperature);                  //Prints temperature
Serial.print("℃");                              //Marks the temperature unit
Serial.println();
Serial.print("***********************************");
Serial.println)
delay(2000);   //fastest is onceevrey 2 seconds
}     //end loop

It should be printing temperature and humidity. If not check the buad rate. Change it to 9600. If it still does not work, this code will print "Hello World!" evrey second to see if you are getting any comunication at all:

//Code
void setup() {
Serial.begin(9600);
delay(5000);
}
void loop() {
Serial.println("Hello World!");
delay(1000);
}

Code

Code

//FirebaseESP8266.h must be included before ESP8266WiFi.h
#include "FirebaseESP8266.h"  // Install Firebase ESP8266 library
#include <ESP8266WiFi.h>
#include <DHT.h> //install DHT Library and Adafruit Unified Sensor Library


#define FIREBASE_HOST "Can be found at Database>Realtime Database at the top" //Without http:// or https:// schemes
#define FIREBASE_AUTH "Can be found in Settings>Service Accounts>Database Secrets"
#define WIFI_SSID "***"
#define WIFI_PASSWORD "***"

#define DHTPIN 4   // Connect Data pin of DHT to D2
int led = 14;     // Connect LED to D5

#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

//Define FirebaseESP8266 data object
FirebaseData firebaseData;
FirebaseData ledData;

FirebaseJson json;


void setup()
{

  Serial.begin(9600);

  dht.begin();
  pinMode(led,OUTPUT);
  
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("Connecting to Wi-Fi");
  while (WiFi.status() != WL_CONNECTED)
  {
    Serial.print(".");
    delay(300);
  }
  Serial.println();
  Serial.print("Connected with IP: ");
  Serial.println(WiFi.localIP());
  Serial.println();

  Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);
  Firebase.reconnectWiFi(true);

}

void sensorUpdate(){
  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  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(F("Failed to read from DHT sensor!"));
    return;
  }

  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.print(F("C  ,"));
  Serial.print(f);
  Serial.println(F("F  "));

  if (Firebase.setFloat(firebaseData, "/FirebaseIOT/temperature", t))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }

  if (Firebase.setFloat(firebaseData, "/FirebaseIOT/humidity", h))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
}
void loop() {
  sensorUpdate();

  if (Firebase.getString(ledData, "/FirebaseIOT/led")){
    Serial.println(ledData.stringData());
    if (ledData.stringData() == "1") {
    digitalWrite(led, HIGH);
    }
  else if (ledData.stringData() == "0"){
    digitalWrite(led, LOW);
    }
  }
  delay(100);
}