Data Hacking

Chapter 12 — GPS Games
Auto TX Delay: This sets the delay (measured in milliseconds) between pressing the
transmit key and sending the GPS data. Set this to 300.
Auto Transmit Rate: This sets the interval between GPS updates. This can be whatever
you want, but you should set it to a short interval initially so you know that the system is
working. I recommend between 5 and 120 initially.
Quiet Time: This sets the duration during which the radio channel must be quiet before
the system transmits a location packet. If the channel is shared with voice, set this to 500.
MIC-E Settings: Leave these options disabled.
Once the preceding settings are specified, the TinyTrak3 is ready for use.
Next, you will need to assemble the TNC. This is available in kit form from http://john.
hansen.net (this is much cheaper than buying a readymade kit, which can be expensive).
Currently, the kit retails at $45. Assembly of this kit is straightforward, but like the TinyTrak3,
it requires some soldering.
Then you need to assemble the cables, of which there are three. Before you begin assembly, you
need a conductor plug that fits the headphone and microphone socket for your radios. These
are available from electrical outlets or you can cannibalize an old set of headphones and microphones
for the job.
The first cable is a GPS-to-serial port cable, the assembly of which is described in Chapter 2.
Next is a cable to connect the TinyTrak3 to the radios. Figure 12-7 shows the wiring details for
the cable to connect the radio to the TinyTrak3.
GND
594837261
+5V
594837261
To TinyTrak
FIGURE 12-7: TinyTrak wiring diagram
299