IoT Based Voice Controlled Home Automation Using NodeMCU & Android.

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This tutorial is all about IoT Based Voice Controlled Home Automation Using NodeMCU & Android. Previously we have made similar types of IoT based Home Automation Projects to control relay from NodeMCU web server. We have used Asyncwebserver to control home appliances from a web browser. But, today we will build our own Home Automation Android App using MIT App Inventor. Install it on Android smartphones and control our home appliances using voice commands as well as buttons.

Table Of Contents

Components Required
Block Diagram of Voice Controlled Home Automation using ESP8266
Circuit: Wifi & Voice Controlled Home Automation Using ESP8266
Android App Voice Controlled Home Automation

Creating an Android App Using MIT App Inventor:
Home Automation App Download Link:

Code to find NodeMCU IP Address
Source Code/Program.

This IoT based voice-controlled home automation project, allows you to interface 2/4/8 channel relay with NodeMCU ESP8266 and control different Appliances like Lights, Fan, AC cooler, Pump, etc. We will use an Android app having Several ON/OFF Buttons and voice-controlled system to send a signal to NodeMCU in order to control relay output. We will assign an IP address to NodeMCU and assign the same IP Adress to the Android App. Because our Android phone and NodeMCU should be connected to the same network for access control. Hence this project is also a LAN based Project.

Components Required

Following are the list of the components that are required for making Voice Controlled Home Automation Project Using NodeMCU ESP8266 WiFi Module.

S.N.	Components	Description	Quantity
1	NodeMCU	ESP8266-12E Board	1
2	Relay Module	4-Channel 5V NPN Relay Module	1
3	LED	5mm LED of Any Color	4
4	Resistor	220 ohm	4
5	Power Supply	5V, 1A Power Adapter	1
6	Connecting Wires	Jumper Wires	10
7	Breadboard	–	1

Circuit: Wifi & Voice Controlled Home Automation Using ESP8266

Here we will use a single channel relay and 3 LEDs connected to NodeMCU GPIOs. Simulating them as home appliances. If you have 4 channel relay you can connect them as below.

Circuit Diagram IoT Based Voice Controlled Home Automation Using NodeMCU & Android

NodeMCU ESP8266 GPIOs	Relay Input Pin
GND	GND
GPIO Pin D1	Input Pin 1
GPIO Pin D2	Input Pin 2
GPIO Pin D3	Input Pin 3
GPIO Pin D4	Input Pin 4
Vin/5v	Vcc

Connect Relay Input Pin with NodeMCU ESP8266 as follows:

Similarly, Connect the 4 output to 4 different LEDs as shown in the figure above.

Android App Voice Controlled Home Automation

The Android App will send a string that must be interpreted by the code to activate each one of the relays defined as follows:

Relay1:
Turn-On: “r1on”;
Turn-Off: “r1off”;

Relay2:
Turn-On: “r2on”;
Turn-Off: “r2off”

Relay3:
Turn-On: “r3on”;
Turn-Off: “r3off”

Relay4:
Turn-On: “r4on”;
Turn-Off: “r4off”

Whenever Android App sends as a command: “r1on”, Relay1 must be turn on. We have also defined “group commands” to turn-on all the relay (“All ON”) and turn-off (“All OFF”) simultaneity all devices. Similarly, the voice input option is also given which when clicked gives a pop up for Google Assistant to Accept Voice Command.

Creating an Android App Using MIT App Inventor:

You can skip this step. Because I have provided the link of the android app file that is directly downloadable. Not only that, but I have also added the link of . so that you can modify the app according to your requirements.

To create an Android App Visit MIT App Inventor website and create a new project.

The main components of this app are as shown in the screenshot below:

Home Automation App Download Link:

If you are a beginner and you don’t know to make any Android App, you can simply download the App from the link below.

http://ai2.appinventor.mit.edu/b/488y

Code to find NodeMCU IP Address

Simply copy the code provided below and upload it to Arduino IDE. After Code is uploaded successfully. Simply click on Serial Monitor and get the IP address of NodeMCU. Now note down this IP as it is required for your Android App.

Code to find NodeMCU IP Address:
#include <ESP8266WiFi.h>
WiFiClient client;
WiFiServer server(80);
const char* ssid = "xxxxxxx";
const char* password = "xxxxxxx";
 
void setup()
{
Serial.begin(115200);
connectWiFi();
server.begin();
}
 
void loop()
{
}
 
/* connecting WiFi */
void connectWiFi()
{
Serial.println("Connecting to WIFI");
WiFi.begin(ssid, password);
while ((!(WiFi.status() == WL_CONNECTED)))
{
delay(300);
Serial.print("..");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("NodeMCU Local IP is : ");
Serial.print((WiFi.localIP()));
}

IoT Based Voice Controlled Home Automation Using NodeMCU & AndroidSource Code/Program:
#include <ESP8266WiFi.h>
WiFiClient client;
WiFiServer server(80);
const char* ssid = "xxxxxxxx";
const char* password = "xxxxxxxx";
String  command =""; // Command received from Android device
 
// Set Relay Pins
int relay1 = D1;
int relay2 = D2;
int relay3 = D3;
int relay4 = D4;
 
void setup()
{
  Serial.begin(115200);
 
  pinMode(relay1, OUTPUT); 
  pinMode(relay2, OUTPUT);  
  pinMode(relay3, OUTPUT);  
  pinMode(relay4, OUTPUT);  
 
  digitalWrite(relay1,HIGH);
  digitalWrite(relay2,HIGH);
  digitalWrite(relay3,HIGH);
  digitalWrite(relay4,HIGH);
      
  connectWiFi();
  server.begin();
}
 
void loop()
{
    client = server.available();
    if (!client) return; 
    command = checkClient ();
 
         if (command == "r1on"  || command == "turn on relay 1"    || command == "relay 1 on")        digitalWrite(relay1,0);
    else if (command == "r1off" || command == "turn off relay 1" || command == "relay 1 off")     digitalWrite(relay1,1);
    else if (command == "r2on"  || command == "turn on relay 2"    || command == "relay 2 on")      digitalWrite(relay2,0);     
    else if (command == "r2off" || command == "turn off relay 2" || command == "relay 2 off")   digitalWrite(relay2,1);
    else if (command == "r3on"  || command == "turn on relay 3"    || command == "relay 3 on")      digitalWrite(relay3,0);
    else if (command == "r3off" || command == "turn off relay 3" || command == "relay 3 off")   digitalWrite(relay3,1);
    else if (command == "r4on"  || command == "turn on relay 4"    || command == "relay 4 on")    digitalWrite(relay4,0);
    else if (command == "r4off" || command == "turn off relay 4" || command == "relay 4 off") digitalWrite(relay4,1);
    else if (command == "allon" || command == "Turn on all devices" || command == "all on") 
    {
      digitalWrite(relay1,LOW);
      digitalWrite(relay2,LOW);
      digitalWrite(relay3,LOW);
      digitalWrite(relay4,LOW);
    }
    else if (command == "alloff" || command == "Turn off all devices" || command == "all off") 
    {
      digitalWrite(relay1,HIGH);
      digitalWrite(relay2,HIGH);
      digitalWrite(relay3,HIGH);
      digitalWrite(relay4,HIGH);
    }
    sendBackEcho(command); // send command echo back to android device
    command = "";
}
 
/* connecting WiFi */
void connectWiFi()
{
  Serial.println("Connecting to WIFI");
  WiFi.begin(ssid, password);
  while ((!(WiFi.status() == WL_CONNECTED)))
  {
    delay(300);
    Serial.print("..");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("NodeMCU Local IP is : ");
  Serial.print((WiFi.localIP()));
}
 
/* check command received from Android Device */
String checkClient (void)
{
  while(!client.available()) delay(1); 
  String request = client.readStringUntil('\r');
  request.remove(0, 5);
  request.remove(request.length()-9,9);
  return request;
}
 
/* send command echo back to android device */
void sendBackEcho(String echo)
{
  client.println("HTTP/1.1 200 OK ");
  client.println("Content-Type: text/html");
  client.println("");
  client.println("<!DOCTYPE HTML>");
  client.println("<html>");
  client.println(echo);
  client.println("</html>");
  client.stop();
  delay(1);
}

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