Arduino - AdHoc Network Setup

Posted by methodMan on Stack Overflow See other posts from Stack Overflow or by methodMan
Published on 2012-09-27T18:25:07Z Indexed on 2012/09/28 21:37 UTC
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I`m currently working with an arduino trying to build an adhoc network to which a device can connect to and send web request to. The problem I am currently having is that I can only set up one connection and then when that connection is terminated (client.stop()) all subsequent connections are not picked up by the server, even a curl command just sits there spinning. The first connection I start when I reset the server works fine and I am able to talk to the server; but after that, the arduino can no longer find new clients (even though it's trying with the library given).

I`m using the sparkfun library for the wifly shield cloned from github, along with an Arduino Uno.

My current code is based off their default example 'WiFly_AdHoc_Example' but I had to remove a few things to get the network to start up which might be the cause of this problem.

Here is the .ino file that I am running.

#include <SPI.h>
#include <WiFly.h>
//#include <SoftwareSerial.h>

//SoftwareSerial mySerial( 5, 4); //Part from example not used(see below)   

WiFlyServer server(80);

void setup() 
{
    Serial.begin(9600);

    //The code below is from the example but when I run it the WiFly will hang
    // on Wifly.begin(). Without it the WiFly starts up fine but only works for
    // one request.
    //mySerial.begin(9600);
    //WiFly.setUart(&mySerial); // Tell the WiFly library that we are not 
                                //using the SPIUart

    Serial.println("**************Starting WiFly**************");
    // Enable Adhoc mod
    WiFly.begin(true);
    Serial.println("WiFly started, creating network.");

    if (!WiFly.createAdHocNetwork("wifly")) 
    {
        Serial.print("Failed to create ad hoc network.");
        while (1) 
        {
          // Hang on failure.
        }
    }
    Serial.println("Network created");
    Serial.print("IP: ");
    Serial.println(WiFly.ip());

    Serial.println("Starting Server...");
    server.begin();
    Serial.print("Server started, waiting for client.");

}

void loop() 
{
    delay(200);
    WiFlyClient client = server.available();
    if (client) 
    {
        Serial.println("Client Found.");

        // a string to store received commands
        String current_command = "";

        while (client.connected()) 
        {
            if (client.available()) 
            {
                //Gets a character from the sent request.
                char c = client.read();
                if (c=='#' || c=='\n') //End of extraneous output
                {
                    current_command = "";
                }
                else if(c!= '\n')
                {
                    current_command+=c;
                }

                if (current_command== "get") 
                {
                    // output the value of each analog input pin
                    for (int i = 0; i < 6; i++) 
                    {
                        client.print("analog input ");
                        client.print(i);
                        client.print(" is ");
                        client.print(analogRead(i));
                        client.println("<br />");
                    }     
                }
                else if(current_command== "hello")
                {
                    client.println("Hello there, I'm still here.");
                }
                else if (current_command== "quit")
                {
                    client.println("Goodbye...");
                    client.stop();
                    current_command == "";
                    break;
                }
                else if (current_command == "*OPEN*")
                {
                    current_command == "";
                }
            }
        }
        // give the web browser time to receive the data
        delay(200);
        // close the connection
        client.stop();
    }
}

If anyone understands this better then I (I`m new to arduino) please leave some helpful comments. Or just help me out on getting this little web server up and running so that I can hit it with more then one request.

If there is any other helpful information I can provide please let me know.

Thanks for reading and hope you can help.

EDIT: Using telnet I can successfully connect (the first time) and send commands to the arduino including one to terminate the connection (calls the client.stop() method). But when I try to reconnect though telnet, it says the connection was successful but on the arduino it's still looping thinking the client is still false. WHAT??? I know right, I'm getting mixed messages from telnet vs arduino. None of the commands work obviously since the ardunio is still looping waiting for a client that evaluates to true. I'm gonna take a look at WiFlyServer from the library I imported and see if I can dig up the problem because somehow that server.available() method isn't finding new clients.

Noticing a lot of TODO's in the library code....

EDIT: So I found the reason for the problem, it was in WiFlyServer.cpp file from the sparkfun library. The code that was causing the reconnect issue was infact in the server.availible() method. Right at the top of the method, there is a check:

// TODO: Ensure no active non-server client connection.

if (!WiFly.serverConnectionActive) {
    activeClient._port = 0;
}

For some reason when I comment this out, I can reconnect fine and everything works as it should. I will now dive into the library and see if I can fix this, I'm not exactly sure what this is doing but it gets called when the server connection is not active and is somehow blocking subsequent connections. Does anyone have any ideas how I might get to the root of this problem without using this commenting hack? Please help, no-one has commented or answered yet!

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