Check out my previous posts on WIFI ESP8266 1.AT COMMANDS  ,  2. TCP CLIENT/SERVER
In this post we shall see how to connect ESP module with an ANDROID Mobile device & communicate.
On ESP side following are the AT commands to configure :
AT+CWLAP   –  Lists all surrounding Access Points
AT+CWJAP = “SSID”,”password”     – Join with your preferred AP
AT+CWMODE=1       ESP on STATION Mode
AT+CIPMUX=1     Allow multiple connections
AT+CIPSERVER=1,80   start the SERVER on port 80
AT+CIFSR    to get the STATION IP Address

Image127
On your Android Mobile open SETTINGS & switch ON WI FI

DSC00139

Surrounding Access Points will be listed automatically.Select the one to which the ESP module has joined already.Here it is MBLAZE , which is a secured one.

DSC00140

Open the preferred WIFI access point & connect to it by providing the Password.

DSC00143
Now , my Mobile has connected to the Access point where ESP is already connected with.

DSC00145

From the Market , install a TELNET client on your Mobile
Image118

Open the TELNET Client
TELNET waits to get the Local Host IP & the Port number.
DSC00149

Enter the IP as 192.168.1.2 & Port as 80  .
This IP is the one we got from AT+CIFSR previously & we’ve started a Server on port 80 already with ESP.
Touch on Connect to Server
DSC00150
Now the TELNET Client is connected to the ESP server on port 80.
Type in some characters & touch Enter

DSC00153

The characters are received by the ESP Module
Image125

To send data to TELNET ,use the AT command
AT+CIPSEND=0,15
This command is to send 15 characters on channel 0

Image126

The message is received by the TELNET screen.

DSC00156