Hardware Reference
In-Depth Information
These are then hidden in plain sight, such as attached under park benches, hanging
from trees, or in the crevices between rocks. One particularly memorable geocache
is secured inside a large hollow tree by a tension pulley system. You reach inside the
tree, pull a ring, and the geocache would drop down. Pull the ring again, and the cache
goes back up inside the tree.
The ideas behind geocaching are not new by any means; people were doing real-world
treasure hunts in the form of letterboxing for years beforehand. But when GPS was
made available to the public in 1991, followed by the ubiquity of highly accurate GPS
systems and the explosion of the Internet, geocaching-type treasure hunting was able
to flourish.
At the time of this writing,
http://geocaching.com
(the primary website for logging and
adding geocaches) is tracking more than two million active geocaches and more than
six million registered geocachers. It is a game that can be played by people of all ages
and abilities, with nothing more than a smartphone and tenacity. The rules of the game
are simple: find as many as you can, be discreet when finding caches, leave the cache
better than you found it, and log your finds (or failure to finds) so that the cache's
activity can be tracked.
There are other complexities:
Exchange items
Goodies, trinkets, toys, and “treasures” are left by geocachers in caches of sup-
portable sizes. The rule of thumb is that if you take one, you also leave one behind.
Travel bugs and geocoins
Tracked objects that move via geocachers from cache to cache.
Travel bug hotels
Geocaches specifically set up to facilitate the drop-off and retrieval of travel bugs.
These are usually found near transportation hubs, such as airports, so that geo-
cachers can help travel bugs move around the world.
Puzzle caches
Geocaches where the GPS coordinates must be decoded from a puzzle.
Multi-stage caches
Sequences of caches where only the first set of GPS coordinates are provided,
and each cache provides another set of GPS coordinates until they lead you to
the final cache (usually a much larger cache with tradable goodies).
While there are any number of smartphone applications (or add-ons for in-car GPS
systems) to help you find geocaches near you, Jeff Clement created the Cacheberry
Pi (
Figure 4-5
) to be embedded in a car. This Raspberry Pi-based project is primarily
intended to show you what the next nearby geocache is in a big, obvious way (as
