Subhajit
Published © GPL3+

Alexa Home Automation System Using NodeMCU & Relay Module

You can easily control light, fan, and other home appliances with the voice commands using the NodeMCU and Relay module.

IntermediateFull instructions provided10 hours15,440
Alexa Home Automation System Using NodeMCU & Relay Module

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board
NodeMCU ESP8266 Breakout Board
×1
Echo Dot
Amazon Alexa Echo Dot
×1
Grove - 2-Channel SPDT Relay
Seeed Grove - 2-Channel SPDT Relay
×1

Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)

Story

Read more

Schematics

Circuit of the Alexa control relay module

Code

Code for Alexa Control Relay module using NodeMCU or ESP32

Arduino
/**********************************************************************************
 *  TITLE: Alexa control 5 channel Relay Module using NodeMCU or ESP32
 *  Click on the following links to learn more. 
 *  YouTube Video: https://youtu.be/tIFEtHVLexw
 *  Related Blog : https://easyelectronicsproject.com/esp32-projects/
 *  by Subhajit (Tech StudyCell)
 *  
 *  Download the libraries:
 *  https://github.com/Aircoookie/Espalexa
 *  
 *  Preferences--> Aditional boards Manager URLs : 
 *  https://dl.espressif.com/dl/package_esp32_index.json, http://arduino.esp8266.com/stable/package_esp8266com_index.json
 *  
 *  Download Board:
 *  For ESP8266 NodeMCU (2.5.1): https://github.com/esp8266/Arduino
 *  For ESP32                  : https://github.com/espressif/arduino-esp32
 **********************************************************************************/

#ifdef ARDUINO_ARCH_ESP32
#include <WiFi.h>
#else
#include <ESP8266WiFi.h>
#endif
#include <Espalexa.h>
// define the GPIO connected with Relays
#define RelayPin1 5  //D1
#define RelayPin2 4  //D2
#define RelayPin3 13 //D7
#define RelayPin4 14 //D5
#define RelayPin5 12 //D6

// prototypes
boolean connectWifi();

//callback functions
void firstLightChanged(uint8_t brightness);
void secondLightChanged(uint8_t brightness);
void thirdLightChanged(uint8_t brightness);
void fourthLightChanged(uint8_t brightness);
void fifthLightChanged(uint8_t brightness);

// WiFi Credentials
const char* ssid = "WiFi Name";
const char* password = "WiFi Password";

// device names
String Device_1_Name = "Room light";
String Device_2_Name = "Blue bulb";
String Device_3_Name = "Yellow bulb";
String Device_4_Name = "Red bulb";
String Device_5_Name = "CFL bulb";

boolean wifiConnected = false;

Espalexa espalexa;

void setup()
{
  Serial.begin(115200);

  pinMode(RelayPin1, OUTPUT);
  pinMode(RelayPin2, OUTPUT);
  pinMode(RelayPin3, OUTPUT);
  pinMode(RelayPin4, OUTPUT);
  pinMode(RelayPin5, OUTPUT);

  // Initialise wifi connection
  wifiConnected = connectWifi();

  if (wifiConnected)
  {
    // Define your devices here.
    espalexa.addDevice(Device_1_Name, firstLightChanged); //simplest definition, default state off
    espalexa.addDevice(Device_2_Name, secondLightChanged);
    espalexa.addDevice(Device_3_Name, thirdLightChanged);
    espalexa.addDevice(Device_4_Name, fourthLightChanged);
    espalexa.addDevice(Device_5_Name, fifthLightChanged);

    espalexa.begin();
  }
  else
  {
    while (1)
    {
      Serial.println("Cannot connect to WiFi. Please check data and reset the ESP.");
      delay(2500);
    }
  }
}

void loop()
{
  espalexa.loop();
  delay(1);
}

//our callback functions
void firstLightChanged(uint8_t brightness)
{
  //Control the device
  if (brightness == 255)
    {
      digitalWrite(RelayPin1, HIGH);
      Serial.println("Device1 ON");
    }
  else
  {
    digitalWrite(RelayPin1, LOW);
    Serial.println("Device1 OFF");
  }
}

void secondLightChanged(uint8_t brightness)
{
  //Control the device 
  if (brightness == 255)
    {
      digitalWrite(RelayPin2, HIGH);
      Serial.println("Device2 ON");
    }
  else
  {
    digitalWrite(RelayPin2, LOW);
    Serial.println("Device2 OFF");
  }
}

void thirdLightChanged(uint8_t brightness)
{
  //Control the device  
  if (brightness == 255)
    {
      digitalWrite(RelayPin3, HIGH);
      Serial.println("Device3 ON");
    }
  else
  {
    digitalWrite(RelayPin3, LOW);
    Serial.println("Device3 OFF");
  }
}

void fourthLightChanged(uint8_t brightness)
{
  //Control the device 
  if (brightness == 255)
    {
      digitalWrite(RelayPin4, HIGH);
      Serial.println("Device4 ON");
    }
  else
  {
    digitalWrite(RelayPin4, LOW);
    Serial.println("Device4 OFF");
  }
}

void fifthLightChanged(uint8_t brightness)
{
  //Control the device 
  if (brightness == 255)
    {
      digitalWrite(RelayPin5, HIGH);
      Serial.println("Device5 ON");
    }
  else
  {
    digitalWrite(RelayPin5, LOW);
    Serial.println("Device5 OFF");
  }
}

// connect to wifi  returns true if successful or false if not
boolean connectWifi()
{
  boolean state = true;
  int i = 0;

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  Serial.println("");
  Serial.println("Connecting to WiFi");

  // Wait for connection
  Serial.print("Connecting...");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    if (i > 20) {
      state = false; break;
    }
    i++;
  }
  Serial.println("");
  if (state) {
    Serial.print("Connected to ");
    Serial.println(ssid);
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  }
  else {
    Serial.println("Connection failed.");
  }
  return state;
}

Credits

Subhajit

Subhajit

25 projects • 43 followers
I have studied Electrical Engineering. I do love to make different DIY electronics projects & share it on my YouTube channel Tech StudyCell.
Thanks to Sohini.

Comments