ESP8266: How to send TCP messages using AT+CIPSEND command - sockets

Question

I am experimenting with Arduino and ESP8266 module, and now I am trying to send some sensor data to a TCP server. For this purposes I am using AT+CIPSTART command (to establish a TCP connection) and AT+CIPSEND to send the data.
If I am testing it using Serial Monitor, it works fine. After entering CIPSEND command I can write some text in a terminal and this message/text will be sent to the TCP server.
When I am trying to make it inside Arduino sketch, then it sends an empty message. The connection works, but I do not see any data.
How can I send a message text (msg) with my TCP packet?
Here is a code snippet
// ESP8266 Client
String cmd = "AT+CIPSTART=\"TCP\",\"";// Setup TCP connection
cmd += IP;
cmd += "\",3103";
sendDebug(cmd);
delay(2000);
if( Serial.find( "Error" ) )
{
debug.print( "RECEIVED: Error\nExit1" );
return;
}
String msg = "test";
Serial.print( "AT+CIPSEND=" );
Serial.println( msg.length() );
if(Serial.find( ">" ) )
{
debug.print(">");
debug.print(msg);
Serial.print(msg);
}
else
{
sendDebug( "AT+CIPCLOSE" );//close TCP connection
}
if( Serial.find("OK") )
{
debug.println( "RECEIVED: OK" );
}
else
{
debug.println( "RECEIVED: Error\nExit2" );
}
}

Answer 1

First of all, Select how much character or byte is needed to transmit. It is better to use softwareSerial library to connect with ESP8266 and send AT commands.
Suppose yow want to send 5 bytes.Type the following AT commands and must give a delay more than 100 millisecond before sending data. Here "\r" is carriage return and "\n" is new line. After including this, ESP8266 can understand you have ended the command.
esp.print("AT+CIPSEND=5\r\n");
delay(1000);
esp.print("Hello");
Your code is not working because you are using unvarnished transmission mode. So to complete a packet you need to transmit 2048 bytes which you are not writing.