John Hansen (W2FS) provided us with a great paper and a pretty entertaining presentation on a special version of his TNC-X he created for use with the Raspberry Pi, called (of course) TNC-Pi.
A Terminal Node Controller (TNC) is… Hell, I think of it as a computer interface to the radio to let you do digital things. I’m sure there’s a more complicated explanation for it. Actual standalone TNCs are relatively rare now, I gather, since much of the work can be done by any soundcard-equipped PC with a halfway decent processor. But that assumes you want to cart around a PC, and even then, you have to set the volume levels carefully, since you’re doing actual real audio-to-digital conversion and back again. A serial port (or, more commonly now, USB) TNC handles that stuff automatically.
Anyway, the TNC-Pi handles the cool interfacing between the Raspberry Pi and the radio. The Pi can then run something exciting and useful, such as the Xastir (“ex”-astir, we learned) APRS client. (APRS is a real-time messaging and tracking protocol over amateur radio and, increasingly, the Internet.) John walked us through the project and how he put it together for remarkably little money; I think it ended up running under $200 for the Pi, TNC-Pi, a small monitor, keyboard/trackpad, and accessories and widgets. At some point I stopped taking notes, but hopefully his presentation will make its way to the TAPR DCC site.
I saw a lot of cool stuff that I didn’t really understand this weekend, but I could easily see the potential of this. First, Raspberry Pi is inherently cool and I’d love to have an application for one. Second, depending on the display (and his example was a 7″ screen for use as a car backup camera), I could probably fit this into my backpack HF kit as well or better than my netbook; certainly it would be easier to power for long periods of time.
The kit is $40 on his site. I hope he sells a ton of them. I wouldn’t mind picking one up myself, but my budget is still recovering from the unplanned FT-817ND purchase last month. And will be for quite a while.