Sunday, March 24, 2013
Friday, March 22, 2013
Wednesday, March 20, 2013
Sunday, March 10, 2013
Once the TNCPi has been assembled, attached to the Raspberry Pi and tested, getting aprx running on it is fairly straightforward.
1) Install the subversion client:
sudo apt-get install subversion
Fetch the aprx sources:
svn co http://repo.ham.fi/svn/aprx src
./configure && make clean all
sudo make install
2) Configure aprx
Refer to the aprx documentation for full details and sample configurations, available at aprx's home page and keep the following in mind:
- The name of the serial device is /dev/ttyAMA0
- Baud rate is fixed at 19200
Note: this is the data rate for the serial interface between the Raspberry Pi and the TNCPi, the RF data rate is fixed at 1200 baud.
The file to edit is /etc/aprx.conf
3) Run it!
To test the configuration, you can run aprx as follows:
aprx -i -vvv -ddd
The switches are:
-i makes it interactive rather than background
-vvv makes the status messages very verbose
-ddd makes the debug messages very verbose
You can stop aprx with ctrl-C to make changes to the file, then start it again with the same command.
There are sample startup scripts in aprx's documentation that you can use to build one to suit your needs.
Once you have the configuration right, you can start it in the background simply by typing:
Saturday, March 9, 2013
I built a TNCPi, which as the name suggests is a TNC for the Raspberry Pi. It has the same footprint as the Pi, takes power from it, and plugs straight into the GPIO pins.
The TNC appears as a serial device on the Pi, /dev/ttyAMA0, with the data rate fixed at 19200 baud, and the on-air data rate is fixed at 1200 baud.
Note the DB9 connector on the photo: it's used to hook up the radio.
It even worked the first time I powered it up! Assembly is a breeze, I'd call it a one evening project. Only basic tools are needed, and the documentation is good. All of the components are provided with the kit.