Until now, you have installed and configured the Arduino IDE for ESP8266 and learned how to control a LED, read an analog input, and dim a LED.

Now it is time to connect ESP8266 to Wi-Fi. Include ESP8266's Wi-Fi library and set up the SSID name and the Wi-Fi password:

#include <ESP8266WiFi.h> 
const char* ssid     = "your_wifi_name"; 
const char* password = "your_wifi_password"; 

In the setup section, Serial is started and configured to send data at 115200 bps; a 10 ms delay is added to allow Serial to finish and the GPIO from 12 to 15 are configured as output and their value is set to LOW:

void setup() { 
Serial.begin(115200); 
delay(10); 
pinMode(12, OUTPUT); 
pinMode(13, OUTPUT); 
pinMode(14, OUTPUT); 
pinMode(15, OUTPUT); 
 
digitalWrite(12,LOW); 
digitalWrite(13,LOW); 
digitalWrite(14,LOW); 
digitalWrite(15,LOW); 

We will start by connecting to a Wi-Fi network:

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

We wait until the status indicates that ESP8266 is connected to the Wi-Fi network. After this, the Wi-Fi connected message is displayed along with the IP address assigned to it by the router. Your router needs to be DHCP capable and have the DHCP feature enabled:

while (WiFi.status() != WL_CONNECTED) { 
delay(500); 
Serial.print("."); 
  } 
 
Serial.println(""); 
Serial.println("WiFi connected");   
Serial.println("IP address: "); 
Serial.println(WiFi.localIP()); 
} 

In the loop section, the code checks to see whether the chip is connected to Wi-Fi and if this is true, the green LED will light on the Witty module:

void loop() 
{ 
if(WiFi.status() == WL_CONNECTED) 
digitalWrite(12, HIGH);   
} 

The Serial Monitor will show the IP address assigned by the router, as follows: