GPS/APRS for Weather Ballon Project

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello all!

This is my first post, and I hope that I am posting into the correct area.

I am involved with a weather balloon project in which we are hoping to track our own payload using APRS. We will be using the Arduino Duemilanove microcontroller and possibly a Tinytrak for the GPS.

I am a newly licensed HAM, and I am also a very new Arduino programmer. I'm sure my questions will be very elementary, so I apologize in advance.

What all is involved, hardware and programming-wise, in tracking our payload using APRS? Will we have to program the Arduino to decode the APRS information, and if so, where can I go to read about the process required? In general, is APRS a standardized data formatting protocol?

What will be required for a ground station? Does that involve a TNC? What software will be required to track the payload?

Any and all information will be greatly appreciated. I feel pretty overwhelmed as this project is an extracurricular activity on top of my 20 credit unit semester, so at this point and just being pointed in the correct direction would be a godsend.

Thanks so much in advance!

2

It's ham, not "HAM".

The Tinytrack is a "tracker", not a GPS. Nearly all TTs are encode-only/transmit-only (the TT4 is the only exception I know of). A tracker is generally a microcontroller based devices that encodes APRS/AX.25 packets and generates the tones for 1200 baud AFSK, which an then be fed to a microphone input of a radio. Typically a tracker has a GPS unit attached so that position data can be encoded, but they can be usefully used without a GPS (e.g. weather stations).

The OpenTracker line of trackers is open source (where the TT line is closed source). I have flown many OTs, and I'd recommend you use them because they're open source, if for no other reason.

If all you need to do is track the balloon, you don't need an arduino.

For the ground station, you'll need a TNC, a computer with soundmodem type decoding software, or maybe use an arduino to implement a TNC (which is a non-trivial project).

The easiest way to decode on the ground is with a Kenwood D7/700/710 APRS radio.

-j