Published March 17, 2021 © GPL3+

ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

How to make an IoT-based ESP32 Alexa Smart Home System to control 8 home appliances with Alexa & manual switches without using any paid App.

IntermediateFull instructions provided7 hours7,437

ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

Things used in this project

Hardware components

Espressif ESP32S

ControlEverything.com 4-CHANNEL RELAY CONTROLLER FOR I2C

Software apps and online services

Arduino IDE

Amazon Alexa Alexa Voice Service

Hand tools and fabrication machines

Soldering iron (generic)

Story

1 / 2

In this IoT project, I have shown how to make an IoT-based ESP32 Alexa Smart Home System to control 8 home appliances from the manual switch & Amazon Alexa App. If the internet is not available, then you can control the home appliances from manual switches. During the article, I have shown all the steps to make this home automation system.

This ESP32 control smart relay has the following features:

1. Control home appliances with voice commands using Alexa
2. Control home appliances with manual switches.
3. Monitor real-time feedback in the Alexa App.
4. Control home appliances manually without internet.
5. Just need Echo Dot. No third-party app required.

Required Components:

1. ESP32 DEVKIT V1 board

2. 8-channel SPDT 5V Relay Module

3. Alexa Echo Dot

4. Manual Switches

Required Components for the PCB

1. Relays 5v (SPDT) (8 no)

2. BC547 Transistors (8 no)

3. PC817 Optocuplors (8 no)

4. 510-ohm 0.25-watt Resistor (8 no) (R1 - R8)

5. 1k 0.25-watt Resistors (10 no) (R9 - R18)

6. LED 5-mm (10 no)

7. 1N4007 Diodes (8 no) (D1 - D8)

8. Push Buttons (8 no)

9. Terminal Connectors

10. 5V DC supply

Required Software:

1. Arduino IDE

2. Amazon Alexa App

Circuit Diagram of the ESP32 Project:

This is the complete circuit diagram for this home automation project. I have explained the circuit in the tutorial video.

The circuit is very simple, I have used the GPIO pins D23, D22, D21, D19, D18, D5, D25 & D26 to control the 8 relays.

And the GPIO pins D13, D12, D14, D27, D33, D32, D15 & D4 connected with switches to control the 8 relays manually.

I have used the INPUT_PULLUP function in Arduino IDE instead of using the pull-up resistors.

I have used a 5V mobile charger to supply the smart relay module.

Testing the Circuit Before Designing the PCB

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Before designing the PCB, I have made the complete circuit using ESP32, an 8-channel relay module, and manual switches.

As you can see, the relay can be controlled from the manual switches and Amazon Alexa App.

In the following steps, I have explained the complete projects in detail, also shared the code and PCB Garber file.

Control Relays With Voice Commands Using Alexa

If the ESP32 module is connected with the WiFi, then you can control the home appliances from Amazon Alexa App and also from the manual switches.

You can control, monitor the real-time status of the relays in the Alexa App. The ESP32, Amazon Echo Dot should be connected to the same WiFi network.

Control Relays Manually With Switches

If the WiFi is not available, you can control the relays from the manual switches.

The ESP32 will check for the WiFi after every 3 seconds. When the WiFi is available, the ESP32 will automatically connect with the WiFi.

Please refer to the circuit diagram to connect the manual switches.

Design the PCB for This Smart Home System

To make the circuit compact and give a professional look, I have designed the PCB after testing all the features of the smart relay module.

You can download the PCB Gerber file of this home automation project from the following link:

https://drive.google.com/uc?export=download&id=1Y8rXnczq6baxAKOrBEE8aro-uqcK0J93

Order the PCB

After downloading the Garber file you can easily order the PCB

1. Visit https://jlcpcb.com/RAB and Sign in / Sign up

2. Click on the QUOTE NOW button.

3. Click on the "Add your Gerber file" button. Then browse and select the Gerber file you have downloaded.

Uploading the Gerber File and Set the Parameters

4. Set the required parameter like Quantity, PCB masking color, etc.

5. After selecting all the Parameters for PCB click on SAVE TO CART button.

Select Shipping Address and Payment Mode

6. Type the Shipping Address.

7. Select the Shipping Method suitable for you.

8. Submit the order and proceed with the payment.

You can also track your order from the JLCPCB.com.

My PCBs took 2 days to get manufactured and arrived within a week using the DHL delivery option.

PCBs were well packed and the quality was really good at this affordable price.

Solder All the Components on PCB

After that, I have soldered all the components as per the circuit diagram.

Then connect the ESP32 board with PCB.

Program ESP32 Using Arduino IDE

Download the code.

First, you have to install the required libraries. I have shared all the links in the code.

ESPAlexa: https://github.com/Aircoookie/Espalexa
AceButton Library: https://github.com/bxparks/AceButton

Then enter the WiFi name, WiFi password & DevicesNames in the code.

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

After that select the DOIT ESP32 DEVKIT V1 board and the PORT. Then click on the upload button.

While uploading if you see the "Connecting.....___" text, press the BOOT button of ESP32.

Configure the Alexa App for the Smart Home System

Open Amazon Alexa App and follow the steps:

1. Tap on Devices. Then Tap on the "+" icon.

2. Tap on "Light", then select "Others".

3. Goto Alexa and tap on "DISCOVER DEVICES".

It will take a minute to add devices. During this time the ESP32 should be connected with the WiFi.

4. Tap on "Devices", and tap on "Lights" to see all the devices.

Testing the PCB With Alexa

After uploading the code, if the ESP32 connects with the WiFi, the blue LED will turn on.

Then you can control the relay module from Amazon Alexa App.

Connect the Home Appliances

Connect the 8 home appliances as per the circuit diagram. Please take proper safety precautions while working with high voltage.

Connect 5-volt DC supply with the PCB. (I have used my old mobile charger)

Turn ON the Supply

Turn on the 110V/230V supply and 5V DC supply.

Finally!! the Alexa Home Automation System Is Ready

Now you can control your home appliances in a smart way.

I hope you have liked this Alexa home automation project. I have shared all the required information for this project. I will really appreciate it if you share your valuable feedback.

Also if you have any query please write in the comment section. Thank you & Happy Learning.

Schematics

Code

Code for ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

/**********************************************************************************
 *  TITLE: Manual (Switch) + Alexa control 8 channel Relay Module using ESP32
 *  Click on the following links to learn more. 
 *  YouTube Video: 
 *  Related Blog : 
 *  by Subhajit (Tech StudyCell)
 *  
 *  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 ESP32 : https://github.com/espressif/arduino-esp32
 *  
 *  Download the libraries:
 *  Espalexa Library: https://github.com/Aircoookie/Espalexa
 *  AceButton Library: https://github.com/bxparks/AceButton
 *  
 **********************************************************************************/

#include <WiFi.h>
#include <Espalexa.h>
#include <AceButton.h>
using namespace ace_button;

Espalexa espalexa;

// define the GPIO connected with Relays and switches
#define RelayPin1 23  //D23
#define RelayPin2 22  //D22
#define RelayPin3 21  //D21
#define RelayPin4 19  //D19
#define RelayPin5 18  //D18
#define RelayPin6 5   //D5
#define RelayPin7 25  //D25
#define RelayPin8 26  //D26

#define SwitchPin1 13  //D13
#define SwitchPin2 12  //D12
#define SwitchPin3 14  //D14
#define SwitchPin4 27  //D27
#define SwitchPin5 33  //D33
#define SwitchPin6 32  //D32
#define SwitchPin7 15  //D15
#define SwitchPin8 4   //D4

#define wifiLed    2   //D2

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

// device names
String Device_1_Name = "Study Lamp";
String Device_2_Name = "CFL";
String Device_3_Name = "Yellow light";
String Device_4_Name = "Night Lamp";
String Device_5_Name = "Studio Light";
String Device_6_Name = "Outdoor Light";
String Device_7_Name = "Kitchen Light";
String Device_8_Name = "Room Light";

// 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);
void sixthLightChanged(uint8_t brightness);
void senventhLightChanged(uint8_t brightness);
void eighthLightChanged(uint8_t brightness);

ButtonConfig config1;
AceButton button1(&config1);
ButtonConfig config2;
AceButton button2(&config2);
ButtonConfig config3;
AceButton button3(&config3);
ButtonConfig config4;
AceButton button4(&config4);
ButtonConfig config5;
AceButton button5(&config5);
ButtonConfig config6;
AceButton button6(&config6);
ButtonConfig config7;
AceButton button7(&config7);
ButtonConfig config8;
AceButton button8(&config8);

void handleEvent1(AceButton*, uint8_t, uint8_t);
void handleEvent2(AceButton*, uint8_t, uint8_t);
void handleEvent3(AceButton*, uint8_t, uint8_t);
void handleEvent4(AceButton*, uint8_t, uint8_t);
void handleEvent5(AceButton*, uint8_t, uint8_t);
void handleEvent6(AceButton*, uint8_t, uint8_t);
void handleEvent7(AceButton*, uint8_t, uint8_t);
void handleEvent8(AceButton*, uint8_t, uint8_t);

boolean wifiConnected = false;

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

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

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

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

void fifthLightChanged(uint8_t brightness)
{
  //Control the device
  if (brightness == 255)
    {
      digitalWrite(RelayPin5, LOW);
      Serial.println("Device5 ON");
    }
  else
  {
    digitalWrite(RelayPin5, HIGH);
    Serial.println("Device1 OFF");
  }
}

void sixthLightChanged(uint8_t brightness)
{
  //Control the device
  if (brightness == 255)
    {
      digitalWrite(RelayPin6, LOW);
      Serial.println("Device6 ON");
    }
  else
  {
    digitalWrite(RelayPin6, HIGH);
    Serial.println("Device6 OFF");
  }
}

void seventhLightChanged(uint8_t brightness)
{
  //Control the device
  if (brightness == 255)
    {
      digitalWrite(RelayPin7, LOW);
      Serial.println("Device7 ON");
    }
  else
  {
    digitalWrite(RelayPin7, HIGH);
    Serial.println("Device7 OFF");
  }
}

void eighthLightChanged(uint8_t brightness)
{
  //Control the device
  if (brightness == 255)
    {
      digitalWrite(RelayPin8, LOW);
      Serial.println("Device8 ON");
    }
  else
  {
    digitalWrite(RelayPin8, HIGH);
    Serial.println("Device8 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;
}

void addDevices(){
  // 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.addDevice(Device_6_Name, sixthLightChanged);
  espalexa.addDevice(Device_7_Name, seventhLightChanged);
  espalexa.addDevice(Device_8_Name, eighthLightChanged);

  espalexa.begin();
}

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

  pinMode(RelayPin1, OUTPUT);
  pinMode(RelayPin2, OUTPUT);
  pinMode(RelayPin3, OUTPUT);
  pinMode(RelayPin4, OUTPUT);
  pinMode(RelayPin5, OUTPUT);
  pinMode(RelayPin6, OUTPUT);
  pinMode(RelayPin7, OUTPUT);
  pinMode(RelayPin8, OUTPUT);

  pinMode(wifiLed, OUTPUT);

  pinMode(SwitchPin1, INPUT_PULLUP);
  pinMode(SwitchPin2, INPUT_PULLUP);
  pinMode(SwitchPin3, INPUT_PULLUP);
  pinMode(SwitchPin4, INPUT_PULLUP);
  pinMode(SwitchPin5, INPUT_PULLUP);
  pinMode(SwitchPin6, INPUT_PULLUP);
  pinMode(SwitchPin7, INPUT_PULLUP);
  pinMode(SwitchPin8, INPUT_PULLUP);

  //During Starting all Relays should TURN OFF
  digitalWrite(RelayPin1, HIGH);
  digitalWrite(RelayPin2, HIGH);
  digitalWrite(RelayPin3, HIGH);
  digitalWrite(RelayPin4, HIGH);
  digitalWrite(RelayPin5, HIGH);
  digitalWrite(RelayPin6, HIGH);
  digitalWrite(RelayPin7, HIGH);
  digitalWrite(RelayPin8, HIGH);

  config1.setEventHandler(button1Handler);
  config2.setEventHandler(button2Handler);
  config3.setEventHandler(button3Handler);
  config4.setEventHandler(button4Handler);
  config5.setEventHandler(button5Handler);
  config6.setEventHandler(button6Handler);
  config7.setEventHandler(button7Handler);
  config8.setEventHandler(button8Handler);

  button1.init(SwitchPin1);
  button2.init(SwitchPin2);
  button3.init(SwitchPin3);
  button4.init(SwitchPin4);
  button5.init(SwitchPin5);
  button6.init(SwitchPin6);
  button7.init(SwitchPin7);
  button8.init(SwitchPin8);


  // Initialise wifi connection
  wifiConnected = connectWifi();

  if (wifiConnected)
  {
    addDevices();
  }
  else
  {
    Serial.println("Cannot connect to WiFi. So in Manual Mode");
    delay(1000);
  }
}

void loop()
{
   if (WiFi.status() != WL_CONNECTED)
  {
    //Serial.print("WiFi Not Connected ");
    digitalWrite(wifiLed, LOW); //Turn off WiFi LED
  }
  else
  {
    //Serial.print("WiFi Connected  ");
    digitalWrite(wifiLed, HIGH);
    //Manual Switch Control
    //WiFi Control
    if (wifiConnected){
      espalexa.loop();
      delay(1);
    }
    else {
      wifiConnected = connectWifi(); // Initialise wifi connection
      if(wifiConnected){
      addDevices();
      }
    }
  }
  button1.check();
  button2.check();
  button3.check();
  button4.check();
  button5.check();
  button6.check();
  button7.check();
  button8.check();
}

void button1Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT1");
  EspalexaDevice* d1 = espalexa.getDevice(0); //this will get "first device", the index is zero-based
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d1->setPercent(100); //set value "brightness" in percent
      digitalWrite(RelayPin1, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d1->setPercent(0); //set value "brightness" in percent
      digitalWrite(RelayPin1, HIGH);
      break;
  }
}

void button2Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT2");
  EspalexaDevice* d2 = espalexa.getDevice(1);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d2->setPercent(100);
      digitalWrite(RelayPin2, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d2->setPercent(0);
      digitalWrite(RelayPin2, HIGH);
      break;
  }
}

void button3Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT3");
  EspalexaDevice* d3 = espalexa.getDevice(2);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d3->setPercent(100);
      digitalWrite(RelayPin3, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d3->setPercent(0);
      digitalWrite(RelayPin3, HIGH);
      break;
  }
}

void button4Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT4");
  EspalexaDevice* d4 = espalexa.getDevice(3);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d4->setPercent(100);
      digitalWrite(RelayPin4, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d4->setPercent(0);
      digitalWrite(RelayPin4, HIGH);
      break;
  }
}

void button5Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT5");
  EspalexaDevice* d5 = espalexa.getDevice(4);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d5->setPercent(100);
      digitalWrite(RelayPin5, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d5->setPercent(0);
      digitalWrite(RelayPin5, HIGH);
      break;
  }
}

void button6Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT6");
  EspalexaDevice* d6 = espalexa.getDevice(5);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d6->setPercent(100);
      digitalWrite(RelayPin6, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d6->setPercent(0);
      digitalWrite(RelayPin6, HIGH);
      break;
  }
}

void button7Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT7");
  EspalexaDevice* d7 = espalexa.getDevice(6);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d7->setPercent(100);
      digitalWrite(RelayPin7, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d7->setPercent(0);
      digitalWrite(RelayPin7, HIGH);
      break;
  }
}

void button8Handler(AceButton* button, uint8_t eventType, uint8_t buttonState) {
  Serial.println("EVENT8");
  EspalexaDevice* d8 = espalexa.getDevice(7);
  switch (eventType) {
    case AceButton::kEventPressed:
      Serial.println("kEventPressed");
      d8->setPercent(100);
      digitalWrite(RelayPin8, LOW);
      break;
    case AceButton::kEventReleased:
      Serial.println("kEventReleased");
      d8->setPercent(0);
      digitalWrite(RelayPin8, HIGH);
      break;
  }
}

Credits

Subhajit

46 projects • 122 followers

I have studied Electrical Engineering. I do love to make different DIY electronics projects & share it on my YouTube channel Tech StudyCell.

ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Required Components:

Required Components for the PCB

Required Software:

Circuit Diagram of the ESP32 Project:

Testing the Circuit Before Designing the PCB

Control Relays With Voice Commands Using Alexa

Control Relays Manually With Switches

Design the PCB for This Smart Home System

Order the PCB

Uploading the Gerber File and Set the Parameters

Select Shipping Address and Payment Mode

Solder All the Components on PCB

Program ESP32 Using Arduino IDE

Configure the Alexa App for the Smart Home System

Testing the PCB With Alexa

Connect the Home Appliances

Turn ON the Supply

Finally!! the Alexa Home Automation System Is Ready

Custom parts and enclosures

PCB Gerber File

Schematics

ESP32 Alexa Smart Home System Circuit

Code

Code for ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

Credits

Subhajit

Comments

Embed the widget on your own site

ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Required Components:

Required Components for the PCB

Required Software:

Circuit Diagram of the ESP32 Project:

Testing the Circuit Before Designing the PCB

Control Relays With Voice Commands Using Alexa

Control Relays Manually With Switches

Design the PCB for This Smart Home System

Order the PCB

Uploading the Gerber File and Set the Parameters

Select Shipping Address and Payment Mode

Solder All the Components on PCB

Program ESP32 Using Arduino IDE

Configure the Alexa App for the Smart Home System

Testing the PCB With Alexa

Connect the Home Appliances

Turn ON the Supply

Finally!! the Alexa Home Automation System Is Ready

Custom parts and enclosures

PCB Gerber File

Schematics

ESP32 Alexa Smart Home System Circuit

Code

Code for ESP32 Alexa Smart Home System With Echo Dot & Manual Switch

Credits

Subhajit

Comments

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