Hardware Hacking Projects for Geeks

233

12

12. How to Build a

Remote Object Tracker

Cost

Time

Difficulty

$100–200

a weekend

moderate

A few years ago I ran across a new offshoot of amateur radio (also called

ham radio) that caught my interest. This offshoot combined two technology

gadgets that I like: GPS and two-way radios. This new system was called

Automatic Packet Reporting System, or APRS. APRS allows you to track the

location of a transmitter with GPS accuracy and view this location data on a

PDA or a laptop computer. I put together one of these systems and had great

fun tracking the location of a friend while hiking. The system also allowed

us to send and receive text messages. Normally, APRS uses licensed ham

radio transceivers to work, but I decided to use unlicensed Family Radio

Service (FRS) radios instead.

In this hack I will show you how to take a couple of these inexpensive, two-

way Family Radio Service radios, a GPS receiver, two small off-the-shelf

circuit boards, and a PDA, and build a mini-LoJack system for your vehicle,

bike, or any other object. Simply install the small black box on a car, a bike,

a motorcycle, or even a person, and view its location on a real-time, mov-

ing-map display via a PDA or a laptop. You should be able to track objects

up to two miles away. The view from the PDA screen will look something

like Figure 12-1.

Credits

All photographs copyright © 2003 Scott Fullam.

Figure 12-1: PDA map view

What You Need

• A pair of two-way radios

(FRS will do)

• A GPS receiver

• A TinyTrack controller (a kit you

will build)

• A Palm OS device or a laptop

computer

• A Terminal Network Controller

(or a TNC kit)

• Other items listed in

Exhibit A

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