8.2 Code

Steps to do coding in Arduino IDE :

1. Open Arduino IDE.

2. For writing this code, we have to add espalexa library.

#ifdef ARDUINO_ARCH_ESP32
#include
#else
#include
#endif
#include
// define the GPIO connected with Relays
#define RelayPin1 5 //D1
#define RelayPin2 4 //D2
#define RelayPin3 14 //D5
#define RelayPin4 12 //D6
//direct callback functions
void device1Changed(uint8_t brightness);
void device2Changed(uint8_t brightness);
void device3Changed(uint8_t brightness);
void device4Changed(uint8_t brightness);
//special callback functions
void devFunc1Changed(uint8_t brightness);
void devFunc2Changed(uint8_t brightness);
void devFunc3Changed(uint8_t brightness);
// device names
String Device_1_Name = “Red light”;
String Device_2_Name = “Green light”;
String Device_3_Name = “Blue light”;
String Device_4_Name = “Yellow light”;
// device_function names
String Dev_Func_1_Name = “Living Room”;
String Dev_Func_2_Name = “Bed Room”;
String Dev_Func_3_Name = “All Home Devices”;
Espalexa espalexa;
boolean connectWifi(); // prototypes
// WiFi Credentials
const char* ssid = “YOUR SSID HERE”;
const char* password = “YOUR PASSWORD HERE”;
boolean wifiConnected = false;
void setup()
{ Serial.begin(115200);
pinMode(RelayPin1, OUTPUT);
pinMode(RelayPin2, OUTPUT);
pinMode(RelayPin3, OUTPUT);
pinMode(RelayPin4, OUTPUT);
wifiConnected = connectWifi(); // Initialise wifi connection
if (wifiConnected)
{ // Define your devices here.
espalexa.addDevice(Device_1_Name, device1Changed);
espalexa.addDevice(Device_2_Name, device2Changed);
espalexa.addDevice(Device_3_Name, device3Changed);
espalexa.addDevice(Device_4_Name, device4Changed);
// Define your devices functions here.
espalexa.addDevice(Dev_Func_1_Name, devFunc1Changed);
espalexa.addDevice(Dev_Func_2_Name, devFunc2Changed);
espalexa.addDevice(Dev_Func_3_Name, devFunc3Changed);
espalexa.begin(); }
else
{
while (1)
{
Serial.println(“Cannot connect to WiFi.
Please check data and reset the ESP.”);
delay(2500);
} } }
void device3Changed(uint8_t brightness)
{ if (
brightness == 255) //Control the device
{
digitalWrite(RelayPin3, HIGH);
Serial.println(“Device3 ON”);
}
else
{
digitalWrite(RelayPin3, LOW);
Serial.println(“Device3 OFF”);
} }
void device4Changed(uint8_t brightness)
{
if (brightness == 255) //Control the device
{
digitalWrite(RelayPin4, HIGH);
Serial.println(“Device4 ON”);
} else
{
digitalWrite(RelayPin4, LOW);
Serial.println(“Device4 OFF”);
} }

void devFunc1Changed(uint8_t brightness)
{
if (brightness == 255) //Control the device
{
digitalWrite(RelayPin1, HIGH);
digitalWrite(RelayPin2, HIGH);
Serial.println(“Living Room ON”);
}
else
{ digitalWrite(RelayPin1, LOW);
digitalWrite(RelayPin2, LOW);
Serial.println(“Living Room OFF”);
}
}
void devFunc2Changed(uint8_t brightness)
{
if (brightness == 255) //Control the device
{
digitalWrite(RelayPin3, HIGH);
digitalWrite(RelayPin4, HIGH);
Serial.println(“Bed Room ON”);
}
else
{ digitalWrite(RelayPin3, LOW);
digitalWrite(RelayPin4, LOW);
Serial.println(“Bed Room OFF”);
} }
void devFunc3Changed(uint8_t brightness)
if (brightness == 255) //Control the device
{
digitalWrite(RelayPin1, HIGH);
digitalWrite(RelayPin2, HIGH);
digitalWrite(RelayPin3, HIGH);
digitalWrite(RelayPin4, HIGH);
Serial.println(“All Home Devices ON”);
}
else
{
digitalWrite(RelayPin1, LOW);
digitalWrite(RelayPin2, LOW);
digitalWrite(RelayPin3, LOW);
digitalWrite(RelayPin4, LOW);
Serial.println(“All Home Devices 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;
}

Demonstration :