Arduino World Mood Light using Twitter and WiShield

This is an implementation of the recent article on instructables.com describing a Twitter World Mood Light, ported to use the WiShield wireless networking device.

I thought that the idea of creating an embedded device that can perform complex analysis of realtime data, and then go on to produce a simplified result to be fascinating. So I had to build one. I just couldn’t bring myself to pay $90 for the WiFly, and found the WiShield at a more palatable $55. The biggest issue with processing web data in a microcontroller is that you just don’t have enough RAM to capture the whole page, so you have to process it in smaller chunks.

The original article is here:
http://www.instructables.com/id/Twitter-Mood-Light-The-Worlds-Mood-in-a-Box/

Even though the Twitter interface is working very well, I currently have my doubts about the LED – it’s not changing to the correct colors at the moment, need to check my wiring, and then take a look at the update routines.

    bool GetHttpWebRequest(char* s)
    {
      // Create the webrequest
      GETrequest getTweets(twitter_ip, 80, "www.twitter.com", s);
      getTweets.setReturnFunc(printData);
      getTweets.submit();
      int count = 0;
      // Process
      while(getTweets.isActive())
      {
        WiServer.server_task();
        delay(10);
        count++;
        // Timeout = 20 seconds approx
        if (count > 2000)
           return false;
      }
      return true;
    }

UPDATE: I found out what was wrong with the LED – the library (as supplied) subtracted color values from 255 when setting the pins, I don’t think this is correct – it should set the color values directly – like this

    // replace this
    analogWrite(m_redPin, 255 - currentColor.r);
    analogWrite(m_greenPin, 255 - currentColor.g);
    analogWrite(m_bluePin, 255 - currentColor.b);
    // with this
    analogWrite(m_redPin, currentColor.r);
    analogWrite(m_greenPin, currentColor.g);
    analogWrite(m_bluePin, currentColor.b);

wherever analogWrite is called in LED.cpp.

UPDATE UPDATE: I had a quick chat with the original developer and his LED could well be an inverse configuration to mine – so this fix might not be necessary, depending on the type of LED you use.