I have a problem, I'm new to Arduino and I'm totally a beginner.
I bought a SIM900 Quad-band GSM / GPRS Shield for Arduino (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221176159800&ssPageName=ADME:X:RTQ:US:1123) and I have two problems. (I use the test code that is found in the library)
First the device does not read every message, but only a few. one read and then 3 does not, then 2 read and then 4 do not read .....
Second I do not know how to connect to xively, no examples. I know how to connect and send data via an ethernet shield, but with SIM900 Quad-band GSM / GPRS Shield do not know how.
I download the library from http://www.gsmlib.org/download.html and fix the first problem with sms.
but I do not find a solution to the second problem, and I can not find and I need a simple example to send data to xively.
So if anyone can help I would be grateful
You'll need to learn how to have the SIM900 perform HTTP operations. Study the example shown in Step 8 at this Cooking Hacks tutorial
For posting data to Xively, study this example.
You'll need to merge how you communicate from the SIM900 with the right HTTP sequences in order to upload data to Xively.