[Renaud Schleck] somehow got lucky enough to find a GPS wristwatch in the trash. It had a broken LCD screen so its wouldn’t be of much use on that next hiking trip, but he knew it still had potential. He used the GPS module and a few other parts to build this reverse geocache box.
Reverse geocache is a container that is locked, opening only in a pre-defined geographic location. We’ve seen plenty of these projects around here, like this one that talks, or this one which was given as a Christmas gift. They’re popular projects both because of the unique method of getting at the prize inside, and because it doesn’t take a whole lot of hardware to build one. Once [Renaud] had the GPS module he simply need a user interface, locking mechanism, and a microcontroller to pull it all together.
The interface uses a screen from an old cellphone and one push button. The latching system is a tiny geared motor salvaged from a Laptop optical drive. These, along with the GPS watch board are all monitored by the STM32 microcontroller which he programmed using OpenOCD and the Bus Pirate.
3 thoughts on “Reverse Geocache Based On STM32 And GPS Wristwatch”
I am the person he offered the box to, I can attest it worked great, and if your are nice, I’ll telle you what was inside !!
I’d like to know: has anyone attempted geolocation spoofing to brute-force any such devices? If so, how long does it take?
Brilliant! This would be the most AWESOME way to propose marriage. If/when I find the one, this will be how I do it.
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