[SOLVED] Hardware Interface Serial Data to HTML > GPRS internet

[alyeomans]

gprs radio microcontroller

Hi

I'm looking at setting up an interface device that will take 2 X streamed serial data sources and do the following:
* save stream data into memory
* display data as dynamic html (webserver) via GPRS modem to the internet

...Or a datalogger ported to the internet

The modem and interface will always be on and will be run from battery so will need to be low power, batteries will be topped up by solar panel.

What modem should i use (include tcp/ip stack)?
As this acts as a webserver, will i need a chipped webserver software? Have not come across documents on how to impliment a simple hardwired webserver.

Any advice would be greatly appreciated.

Thanks
Alex

 

[GSM Man]

gprs internet hardware

You'll need a GSM-radio module coonected to a microcontroller. I use the SIM300D and SIM340D from SIMCom. These support GPRS and have a built-in TCP/IP stack.

There are hundreds of low-power microcontrollers on the market. You'll need to consider your other requirements to determine which is best for your project. Microchip has an on-line product selector that allows you to enter the features you need and it will provide a list of controllers matching those - https://www.microchip.com/maps/microcontroller.aspx.

The code for a web server is fairly simple if you already have a functional TCP/IP stack. Basically it receieves a GET or POST request, parses the arguments out of the request and sends the web page. We'll need to add code to include your data on the page. Typically this is done using 'tokens' embedded in the web page source. Your program replaces those tokens with specific data.

Microchip has a free TCP/IP stack for their processors (**broken link removed**). It's designed to connect to the Internet via their Ethernet controllers and most of the code is for the lower protocol layers. However, there's enough documentation to explain how it works and you could extract just the HTTP server code from it.

For your device to act as a server, people will need to make a connection to it. You'll find that most service providers will block in-coming request unless you have service contract that supports that. For some carriers this will require you to get an expensive data plan.

 

[alyeomans]

Thanks GSM Man. Your post gave me much food for thought and thus the huge delay in replying. I thought it may be interesting to post the actual used design.

A micro controller takes multiple inputs from the various sensors - serial and logic inputs. The micro sends serial out to a GPRS modem to the internet in an AT command format. The data is send by a form post or get in html format. The posted data is then saved to a database.

With this type of regular communications it was also possible to change settings remotely once the connection was established - but this was not needed in the end.

Alex