[Update: Apr-17-2012]

I have a working library for initializing AT-command compatible modems for TCP/IP over cellular.


Protocols: TCP and UDP (both work)

Mode: Transparent Bridge

Rate: 57600 baud

GCS tested: MP and QGCS

HW: APM1 tested, (APM2 testing soon)

Modems Tested: DroneCell (SIM900D module) and Arduino GSM Shield (SIM900 module)

Development continues...

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If you look at the developers website of drone cell, he has sketches for tcp/ip and all the like... I would start there... also arduino has some good code snippets on their website... 

Eirc over at narobo (dronecell creator), has been very helpful. I have all the docs. I also found some working init scripts... 

I just received the dronecell today, so let's see..

Got the basic init script for "Transparent mode" UDP forwarding on the DroneCell working.

I also have it incorporated into the APM code so that it happens on startup, cleanly and automatically. 

DroneCell is responding and setting up the UDP "connection" (yeah, I know...). 

Possible first field test this weekend

Is there anyone in this group who has a DroneCell and wants to help with testing?

No additional boards, connected directly.

It will work fine with an APM1 2560, I'm testing that as well as an APM2. 

You will also need a SIM card (if your phone has one, and it is GSM, then you can use it. It will need a data plan. The code uses only IP (TCP + UDP), so no SMS charges, or call charges. 

There are a whole lot of different GSM modules out there.

You could try a different brand. 

Are you handy with a soldering iron?

European sources: 



You would need to make sure that the voltage from the Telemetry port is appropriate, or regulate it with some additional components. You will also need a SIM card slot/holder. Perhaps you can find other, more "ready to fly" boards in other European outlets, I honestly don't know the market. 

From a software perspective, it uses an AT command set that is similar (if not identical) to the one on the dronecell module. Whatever code I develop for the DroneCell, will assume that people will have a variety of modules and should be easily portable to other GSM modules. Probably be auto-detected and supported out of the box, since you can ask the modem for a brand name and then pick the appropriate init-string and behavior. 

No guarantees any of it will work, but in principle, we can develop an appropriate AT command to initialize and manage any IP-capable brand of GSM modem. 

Yes,I would test it. Today I am using another to initialize the game module.
Do you detect disconnect ? and blind it up again after GSM loss ? How do you give feedback if connection/UDP failed?

Andke: I do not detect *anything*.

The only code I have so far is a very rudimentary module for initializing the modem from the APM (ie using the APM to send the AT commands before the GCS starts sending.). Once the basic functionality is working and tested, I can add features. For now, I'm just looking to get it working.

I will have code ready for testing this coming week. It's almost ready!


I think that GSM/GPS tracker *will* work!!

It seems to be just a GSM/GPRS quad band modem.

Can you find an AT command set manual?

Can you see if it has serial pins or pads somewhere? Like "TX", "RX"?

From the manufacturers specs, it is a full cellphone and supports voice calls, so it must have a serial console somewhere for AT commands. If it does and you can connect it, it will work!

Ask the manuf. for an AT-command manual and we are in business. If they can't help you, look at the GSM chip (probably on the underside from the photo you sent), and see the model number and brand. It might be a common module like a Telit or SIM800 or something, in which case there will be lots of manuals. If you do not find a manual, we could try standard AT commands and see what happens.

I can't see from the photo.

The GSM module is the one covered in Velcro. Can you see under the Velcro if there is a brand name or model?

hm, that's tough.

I will post a status update on the main thread now.

I found these, if you can order from Amazon:


They use the SIM900 which is the same as on the DroneCell, if you want to try. 


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