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31  Using Arduino / Networking, Protocols, and Devices / Re: Ethernet stability on: March 08, 2013, 06:37:09 am
Thanks for your input smiley
I have tweaked and adjusted and tried many things but the end result is the same which is after one or two days, it locks-up.
To keep things happening, the watchdog reboots the board and it all seems happy again. Its transparent to the user, the only way I know its happened is an uptime timer on the web-page.
Perhaps I'm just trying to do too much on the one board..
NTP lookup, web-server for control/status and client for posting logging data.
I just dont understand C or C++ well enough to dig deep down. In time perhaps.....
Meantime, I have written a server and client for the wiznet in assembly language. Its a fraction of the size, but not as comprehensive. DNS and NTP still to do....
Driving the W5100 at register level has been quite educational. I certainly learned a lot about the structure of web transactions.
With the low-level access, its easier to see whats going wrong. This highlights the lack of useful diagnostic and status info that is 'missing' from the ethernet library, which is basically a go/no-go affair but nothing available to show whats going on in the background, or at what point something failed.

Now that I know a lot more about the chip, I can have another try at the C-code and see if it makes more sense.

32  Using Arduino / Networking, Protocols, and Devices / Ethernet stability on: February 04, 2013, 03:12:46 am
Hi all,
An outline of what I have is....
An RF network of RFM12 nodes with 1-wire temp sensors and an RFM12-enabled 4 output mains power switch (for lights or whatever) . These communicate to a 'gateway' that collects the info from all the RF nodes and deals with command/responses for the power-switch box.
The gateway links to an Ethermega by RS485.

On the Ethermega, I run a webserver that displays some of the temperatures and lets you turn on/off the 4 power outputs.
Also on the  Ethermega, a client logs the temperatures to both nimbits and thingspeak (every 60-sec for Thingspeak, 90-sec for nimbits).
On startup, the time is retrieved from a NTP timeserver and each midnight thereafter.

What I notice is that when using the client connect with a name lookup, ie, NOT a fixed IP, the client side of the Ethermega eventually hangs up. This can take  up to 6-hrs or even after 20-min , but the server side continues to work when the client side stops.

I am currently trying the client side (logging) with fixed IP addresses (which is not a long term solution) and at the same time the ethermega server is being worked by having a autorefresh request from firefox every 10 sec.
Since moving to fixed IP addresses for the logging, the system has been stable for 24 hours (longest ever!) now of logging to two sites and serving up a webpage every 10 seconds without a hitch ( over 8600 page refreshes).

While trying to investigate this I came across a Wiznet errata document (W3150A+/W5100 Errata Sheet) on the W5100 chip about possible errors relating to ARP requests but I am a very inexperienced at C and I lack the understanding to figure out if the fix for the errata has been included in the ethernet library, or even if the client failure while using lookups could be caused by this so I'm hoping for someone with better C/C++ understanding who has looked into this and may be willing to share their experiences and understanding.

I include the logging code here so perhaps someone may spot something I'm doing wrong. It is only a section of the complete code.

When the client side accumulates 5 successive failures, the whole system is reset by the WDT. I have never had a problem with the ethernet not coming back after a reboot.

Is there any way to check how many W5100 sockets are currently available?

Any help/suggestions gratefully received  smiley



posts to nimbits

Uses the PString.h library.
Instead of making many connections to the server using the usual Arduino ethernet functions
like 'client.print' (every statement is a separate trasnaction), all the data to send in the
POST trasaction is 'assembled' into one large string using the Pstring library,
which then gets sent in one hit. This reduces the IP traffic considerably

void do_weblog() {
    // if 'postinginterval' secs have passed since
    // your last connection, then connect again and send data:
    if((millis() - lastCloudTime > postingInterval)) {
        sendData();    // the POST happens here

// this makes a HTTP connection to the logging server:

void sendData() {

byte cloud[] = { 74, 125, 31, 121 }; //

        str.begin();    // reset the into-string pointer. This is the 'main' string being assembled.
        cont.begin();   // and for the actual content ie payload string

// Create the 'content' of the string to send. Its assembled from the user details, then the sensor data
// 1st part of content is access details
        cont.print("email=XXXXXXXXXXXXXXXX&key=YYYYYYYYYYYYYY");    // store in the string 'cont'

// the sensor data is aquired from the RFM12 gateway that receives all the assorted temp sensor data
// get the data and store it in the 'cont' string. Data is requested from the RFM12 'gateway' using RS485.
        GetTemperature(0);        // hot water address
        cont.print(temptemp);    //
        GetTemperature(5);        // turning circle sensor adress
        cont.print(temptemp);    //
        GetTemperature(7);        // library sensor address
        cont.print(temptemp);    //
        GetTemperature(6);        // freezer in pantry address
        cont.print(temptemp);    //
        GetTemperature(1);        // workshop address
        cont.print(temptemp);    //
 // now get the length of the assembled content string. This string is the complete 'content'
        int contlen = (cont.length());
 // Got the content assembled so try and connect to the web-site

    EthernetClient Logging_client;      // client for both logging services
    Serial2.println("Attempting to connect to Nimbits...");

    if (Logging_client.connect(cloud, 80))
//    if (Logging_client.connect("", 80))
        str.println("POST /service/batch HTTP/1.1");
        str.println("Connection: close");
        str.println("Cache-Control: max-age=0");
        str.print("Content-Length: ");
        str.println("Content-Type: application/x-www-form-urlencoded");
        str.println(cont);    // the actual content (data points)

// the total string ('post' headers and content) is sent to the ethernet connection in one hit
        Logging_client.print(str);  // ethernet send to COSM

        Serial2.println();        // for debug
        Serial2.print(str);       // this is a copy of whats sent to the ethernet (same string)
        Serial2.println();        // for debug
        Serial2.println();        // for debug

      bufindex = 0;

// look for response
    while (Logging_client.connected()) {
      if (Logging_client.available()) {
        char c =;
        if (bufindex < 198) {
          //store characters to string
         content[bufindex] = c;
         bufindex = bufindex+1;
      content[bufindex] = 0;

    if (strstr(content, "200 OK") != 0) {
       failcount = 0;    // reset after every successfull connect
    else {
        // if you couldn't make a connection:
        failcount = failcount + 1;
// The above is when the connection succeeds and data is sent/received   

// if the connection fails then here is next
    else {
        // if you couldn't make a connection:
        failcount = failcount + 1;
        Serial2.print("Connection failed ");
// and after here for either good or bad connection
      Logging_client.flush();    // ensure no data left in buffer (wont allow close if present)
      Logging_client.stop();     // and finish the socket

      Serial2.print("failcount ");

        if (failcount > 5) {    // if connection consistently failing then reboot.
          WDTreboot();        // sets up an 8-sec timeout
    lastCloudTime = millis();

33  Using Arduino / Networking, Protocols, and Devices / Switching between ethernet client & server on: April 20, 2012, 12:17:07 am
This is probably a simple one when you know what your doing or can dig into the library code in the ethernet files but I am having difficulty in figuring out how to switch between my ethernet board being a server then switching to a client and back again.
I have an embedded application that allows me to switch lights on and off & display the temperature of my solar hot water system. The web side of it runs on an ethermega and as it serves my pages, embedded tokens get filled in by the real-world data (via RS485 & RFM12 links). This all works OK.
Now what I would like to do is from time-to-time, send some of the temperature data to Pachube but I cant figure out how to stop the board being a server and switch to a client to allow the Pachube stuff, then back to a server again.
Any help with this would be appreciated.
I am not a 'C' programmer but bit by painful bit I'm getting less worse. Usually I write embedded stuff in assembly but as Arduino seemed the way to go for the web-interface side, I'm slowly trying to get there....
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