Check out Flickr user Rumtopf’s fancy take on the reverse geocache box. For those who don’t know, a reverse geocache is a box that unlocks itself when the GPS sensor inside senses that it’s in a specific spot on the globe. Rumtopf used a snazzy doorbell button to wake an Arduino, which checks the GPS and displays the distance from that spot on an LCD. He also used a magnetic child safety lock as a backdoor to access the inside of the briefcase in case of malfunction. And if you’re ever in a position which requires you to solve a reverse geocache, he also created a web-based utility to help narrow down the location and unlock your prize, whatever it may be. [via the MAKE Flickr pool]


Matt Richardson

Matt Richardson

Matt Richardson is a San Francisco-based creative technologist and Contributing Editor at MAKE. He’s the co-author of Getting Started with Raspberry Pi and the author of Getting Started with BeagleBone.

  • Jeff Highsmith

    Wow, I just discovered that this project was covered in Make! Cool, way to go, little suitcase! To clarify on the solving page, I intend it only for builders of puzzle boxes to test their math, not for recipients to open their gift. It shouldn’t be too easy. Break out the topographical map and build yourself a nail-and-pencil-on-a-yardstick compass to draw those circles. :)