Reverse GeoCache puzzle gets downsized

[Markus] built his own reverse geocache puzzle box but on a smaller scale than the original. His is based around a PIC 18F2520 and powered by two AAA batteries. The user interface includes one button, a 16×2 character LCD, and a piezo speaker. The box unlocks itself when the GPS module inside detects the proper location on the globe. There is also a secret code that can be tapped on the button to unlock the box prematurely, and another to show the locations in which the user attempted to open the box. This build doesn’t leave much room for a payload, but [Markus] did a great job designing the board and making the components fit as efficiently as possible.

Frustromantic Box, a reverse Geocache

One of the best feelings in the world is when one of our posts inspires a fellow hacker to plan, create, and execute his or her own project.

[Russ] let us know about his Frustromantic Box which he gained inspiration from the original Reverse Geochache we posted about. For those out of the loop, the box is locked and will only open in a certain location. The current distance to the  location is displayed on the screen when a button is pressed, and usually there is a limited number of button presses (3 presses for those that know geometry, 50 for everyone else). As soon as the box is at location, it will open.

The Frustromantic Box uses an Arduino, classic HD44780 display, a servo, and the pièce de résistance EM406 GPS. All built in time to frustrate his wife for Christmas.

Reverse geocache puzzle


[Mikal] wanted to create an awesome electronic wedding gift for his friend who was moving to France. After experimenting with a few things, he settled on creating a puzzle box that would only open in a certain location. Since his friend introduced him to the Arduino, he fittingly used one in the design, along with a serial GPS module and a mini character LCD. The box itself is locked using a servo-controlled chopstick, which could theoretically be snapped if [Mikal] really screwed something up. To save battery life, he used a small Pololu module to provide power that uses only 0.01 microamps in standby, and can be shut off by the Arduino.

The box was designed to be mysterious yet self-explanatory. When the button on the front is pushed, the box comes to life for 3 minutes, displaying the distance away from secret location. Additionally, it warns how many tries are left: the button can only be pushed 50 times before it is sealed “forever”. In order to open the box, you have to be within 2km of the destination. Theoretically, you can narrow down the location to one of 2 points after 2 readings, but a less scientific approach would probably be a lot more fun.

This seems like an amazing gift, and the same concept could be repurposed into hundreds of other devices. For extra fun, he could have placed it at a geocache location.