Table of Contents
In this post we will see how to control an LED connected to NodeMCU using Google Firebase. We will see how to create a database in firebase and then establish communication from NodeMCU to Firebase to control the LED from anywhere.
What is Google Firebase ?
Firebase is Google’s database platform which is used to create, manage and modify data generated from any android application, web services, sensors etc. For more information on Firebase please visit the official website of Firebase.
Benefits of Using Google Firebase
- You can operate LED from anywhere using Internet (on Global Sever)
- Your Data will be stored and can be accessed anytime from anywhere
- Google Firebase is easy to understand and free for up to 10 GB data, which is sufficient for Home based Projects
Setting Up NodeMCU With LED
Before starting with Google Firebase, we need to set up the LED to NodeMCU. So, refer the components required section and connection figure below.
Components required
- NodeMCU ESP8266(12E)
- Resistor (100 Ω)
- An LED
LED Connection from NodeMCU
- Positive terminal of LED to D3 Pin of NodeMCU (Via Resistor)
- LED Negative terminal to GND Pin of NodeMCU
Refer the fig. for Connection :
Adding Required libraries for Firebase Connection
Their are two libraries which need to be downloaded for connection to Google Firebase in your Arduino IDE
- Arduino JSON
- Firebase Arduino
To Download Arduino JSON
Open Arduino IDE << Go to Tools << Library Manager << Search “arduino json” << Download “ArduinoJson by Benoit Blanchon”
Refer the Fig for Library:
To Download Firebase Arduino
Open Arduino IDE << Go to Tools << Manage Library << Download ZIP file of Firebase Arduino library from GitHub << ADD ZIP File
GitHub Link for Firebase Arduino Library : https://github.com/FirebaseExtended/firebase-arduino/blob/master/src/Firebase.h
Setting Up Firebase Console
Create a Project by going to : https://firebase.google.com/
Once your Project will created you’ll see :
After that create Realtime Database by going to Realtime Database Console :
Set the database in “Test Mode” :
Once your Realtime database is created , Copy the Database URL and Create a Node with Name “LED_STATUS” keeping in “off” , Refer the figure below :
Now copy the Authentication Database Secret key by going into Project settings, refer the fig below :
Copy the Database URL and Authentication Database Secrets key in Notepad, since they will be required in programming
Programming NodeMCU for using Google Firebase
Firstly include the libraries for using NodeMCU and firebase
#include <ESP8266WiFi.h #include <FirebaseArduino.h
Define Firebase Database URL and Authentication Database Secrets Key
#define FIREBASE_HOST "your-project.firebaseio.com" // Database URL #define FIREBASE_AUTH "06dEpqanFg***************qAwnQLwLI" // the secret key generated from firebase Database Secrets
Define SSID (WIFI Name) and Password for Internet Connection
#define WIFI_SSID "xxxxxxxxxxxxx" // input your home or public wifi name #define WIFI_PASSWORD "xxxxxxxxxxxxxx" //password of wifi ssid
Initialize Wifi and Firebase Connection
WiFi.begin(WIFI_SSID, WIFI_PASSWORD); //try to connect with wifi while (WiFi.status() != WL_CONNECTED) { Serial.print("."); delay(500); } Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH); // connect to firebase
Setting Firebase String and Get request commands
Firebase.setString("LED_STATUS", "OFF"); //send initial string of led status fireStatus = Firebase.getString("LED_STATUS"); // get ld status input from firebase if (fireStatus == "ON" || fireStatus == "on") { // compare the input of led status received from firebase Serial.println("Led Turned ON"); digitalWrite(LED_BUILTIN, HIGH); // make bultin led ON digitalWrite(led, HIGH); // make external led ON } else if (fireStatus == "OFF" || fireStatus == "off") { // compare the input of led status received from firebase Serial.println("Led Turned OFF"); digitalWrite(LED_BUILTIN, LOW); // make bultin led OFF digitalWrite(led, LOW); // make external led OFF } else { Serial.println("Wrong Credential! Please send ON/OFF"); }
After Flashing this code you can go to your Realtime database console and change the LED_STATUS to “on” and observe that your LED will glow
Full Code:
#include <ESP8266WiFi.h> // esp8266 library #include <FirebaseArduino.h> // firebase library #define FIREBASE_HOST "your-project.firebaseio.com" // the project name address from firebase id #define FIREBASE_AUTH "06dEpqanFg***************qAwnQLwLI" // the secret key generated from firebase #define WIFI_SSID "xxxxxxxxxxxxx" // input your home or public wifi name #define WIFI_PASSWORD "xxxxxxxxxxxxxx" //password of wifi ssid String fireStatus = ""; // led status received from firebase int led = D3; // for external led void setup() { Serial.begin(9600); delay(1000); pinMode(LED_BUILTIN, OUTPUT); pinMode(led, OUTPUT); WiFi.begin(WIFI_SSID, WIFI_PASSWORD); //try to connect with wifi Serial.print("Connecting to "); Serial.print(WIFI_SSID); while (WiFi.status() != WL_CONNECTED) { Serial.print("."); delay(500); } Serial.println(); Serial.print("Connected to "); Serial.println(WIFI_SSID); Serial.print("IP Address is : "); Serial.println(WiFi.localIP()); //print local IP address Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH); // connect to firebase Firebase.setString("LED_STATUS", "OFF"); //send initial string of led status } void loop() { fireStatus = Firebase.getString("LED_STATUS"); // get ld status input from firebase if (fireStatus == "ON") { // compare the input of led status received from firebase Serial.println("Led Turned ON"); digitalWrite(LED_BUILTIN, LOW); // make bultin led ON digitalWrite(led, HIGH); // make external led ON } else if (fireStatus == "OFF") { // compare the input of led status received from firebase Serial.println("Led Turned OFF"); digitalWrite(LED_BUILTIN, HIGH); // make bultin led OFF digitalWrite(led, LOW); // make external led OFF } else { Serial.println("Wrong Credential! Please send ON/OFF"); } }

I am a Embedded System and IoT Developer , I work on Firmware and Electronics Designing , Currently in 3rd Year pursuing Btech from Guru Gobind Singh Indraprastha University , Delhi in Electrical and Electronics Engineering