Archive for September, 2007
A TinyTrak is a small APRS tracker available for puchase from Byonics. It interfaces with a GPS unit and is tiny enough to fit into a vehicle or carry with you while on a hike. These diverse little units are able to decode incoming serial data (be it from a computer or GPS device,) and then re-encode it into 1200 baud AFSK for broadcast on a radio. The power consumption is very low, making it ideal for environments where power may be limited.
I chose to have the TinyTrak sent to me unassembled. This saves $10 off of the base price and makes for a fun hour of assembly.
The assembly is not difficult, and in fact serves as a great project for those wishing to learn basic soldering skills. Byonics ships the TinyTrak with easy to follow assembly instructions.
The next step is to assemble a cable for your brand of radio. I decided to use it alongside my Kenwood TM-V7, since it normally does not have APRS capability. Later, I will interface it with a more rugged Motorola Maxtrac radio, which will be used soley for APRS. The TM-V7 utilizes a 6-pin Mini-DIN socket, exactly the same as a computer PS2 plug, to send and receive digital data. This makes it easy to sacrifice an old computer PS2 cable. You can see the cable plugged in to its socket on the left-hand side of the radio in the picture below.
The Maxtrac makes use of a 16-pin connector, similar to old floppy and IDE cables, but with fewer pins. Again, sacrificing an old floppy cable to create an interface for the TinyTrak is easy.
Surprisingly, the toughest part of this project was assembling the cable. I spent hours scouring the Internet for accurate interface diagrams before I realized that Byonics had great radio interface diagrams on their website. I wholeheartedly suggest that you look there for a diagram, first. You can click here to see what the diagram for the TM-V7 cable looks like.
After that, it’s a matter of plugging the TinyTrak into a computer to program it via the serial port. The software used to program the device runs on Win32, but fortunately there are lots of old Win32 machines lying around doing nothing. I configured the TinyTrak to beacon every 30 minutes while stationary, and every 60 seconds while on the move.