Hi All.
I am/have been working on a data-logger graphing device for RS232 Devices. and i want to bring it into the 21 century by adding WiFi capability. its running on an Arduino Mega 1280 (hopefully will be updating to the Due in some time). I have an RN-XV wifi socket that i plan to use. I am hopeing to beable to do 2 things with it.
host a website. that is self updating with streaming data. (data comes in once every 30+seconds) that has a graph of all the data. and That can select between different files on the sd card to graph and display. (only the newest file will have new data).
send an email/notification somehow when the data is below a set point.
My question is what is the most complete library to start from? compatible with Arduino 1.0.1 or greater.
Also is it even posible for the RN-XV/WiFly to upload data from an SD Card?
To generate graphs the Mega1280 is not equipped with enough RAM. You'll get such things a lot cheaper if you use one of the routers capable of running OpenWRT, there you have all the graphing utilities you need for such stuff and the WiFi for free. If you buy one with an USB port you can connect a simple Arduino (like the UNO) to do the low level stuff.
Also is it even posible for the RN-XV/WiFly to upload data from an SD Card?
Yes, this is possible but it won't be very fast.
If you wanna use your RN-XV, use it only for the data transfer to a web server and do all the graphical stuff there.
i was hoping to beable to use RGraph.net on the Arduino. Tied in with AJAX. (i am clueless on website stuff.) so its not realy graphical.
I understand the limits of ram, expecialy since i already have an LVDS 3.2" display and touch screen running, displaying a graph, parsing data from an RS232 DataStream, calculating max, min, avg, and St.Dev, on the fly. adding Unix timestamp and saving to an SD Card and printing on a thermal printer.
I figured a website wouldnt use much RAM. all the files/data stored on the SD Card. when a request for one of the pages is made the arduino responds with that page. if its a request for the active file, the requested page would poll for new data periodically.
This way your doing the graphical stuff on the client. This is possible but still the Arduino with the RN-XV is limited to about 10kB/s because it's communicating over the USART with the Arduino. The libraries folder of RGraph.net is about 1.6 MB. If the client has to pull all the stuff contained there it needs about 3 minutes just to get that from the Arduino. So although your idea is possible it's not practical. If you use another web server and just get the data from the Arduino, you're fine because transferring the data doesn't need that much bandwidth.