Data Hacking

FIGURE 11-30: A Glowring
Chapter 11 — Hacking Geocaching
Glowrings are designed to be attached to key rings to make them easy to find in the dark. They
work because they contain a tiny vial of radioactive tritium gas. This radioactive gas emits electrons
as it decays, and these electrons strike the phosphorescent coating inside the vial, causing
a faint glow of light to be emitted. These devices have a very long life span (over ten years) and
require no maintenance.
Glowrings come in a variety of colors, but green is usually the brightest.
All you need to do to add a Glowring element to your GPS is get yourself one (do an Internet
search, which will bring up a whole raft of suppliers) and some good glue (epoxy is best).
When you get the Glowring, take a sharp knife and carefully split the casing in half along the
join, as shown in Figure 11-31.
This exposes the fragile glass vial containing the tritium. Take great care not to break this! Set
it aside safely for a moment.
When you have the two halves, carefully remove the lug from one of the halves to make a flat
surface.
Epoxy the plastic, along with the glass vial, to the GPS case, as shown in Figure 11-32. Don’t
glue it to the screen, to the buttons, or over the antenna. Anywhere else should be fine.
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