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GPS Puzzle Box


A couple of american friends got married in may (Novastar and his wife Jen) and I wanted to participate & do something useful for that special event but it's wasn't easy from France, not having any contact with the families (couldn't be in touch without disclosing my surprise since I had to ask my friends).
Inspired by this excellent projet, I decided to build my own version of the GPS puzzle box !

The project went here and there, and finally with some friends we decided to collect some fund for their honeymoon trip in France. I collected the money using a very handy paypal widget often used for supporting open source projects like wikipedia, it allows you to setup a target "goal" for the pot and has a thermometer indicating how much you gathered so far.

It was then a e-treasure but I wanted the whole thing to stay in touch with the real world, human beings and tangible objects.
I then started by building the box itself, hand dyed with a dark brown and a clear satin coat to protect the wood, then I galv-etched some metal discs, trying to mix metal colors in a nice way (brass & copper).

Then I worked on the electronics, using a salvaged and dirty crystal focus 4.3 PCB (minus the motion sensor and the luxeon driver). The main difference with the original project is that I didn't use any screen or switch, it's a talking box !
I recorded my own voice, changed it using goldwave to have a bit of a droïd hidden in there, and I also lowered my pitch to sound more like a cave troll for certain messages. The GPS head was F5-scored during sparkfun free day !

The box is built like a saber, with a recharge port, and I knew Matt could recharge it if needed. Two 14500 li-ion cells in a 2xAA battery holder and a little speaker et VOILA ! The electric latch is a simple solenoïd device I got on the shelf, with an additionnal brass rod to reach the eyebolt securing the lid.
I initially thought of a secret electronic backup solution to open the box in case of emergency but I finally went for a simple & mechanical one, using a decoration hex screw that looks like it's securing the 5 eurocents on the right side of the box, but it's just hidding a little hole that allows to push the latching pin to unlock the box. The 5 € cents represents also "my 2 cents" to their wedding, I went for the 5 cents coin cause... well with € going down and inflation... wait no... the 2 cents coin was too small to have the screw fitting nicely.

The built took me about 3 days plus a few hours of debugging my GPS coordinates calculation routines. I had only access to 24 bit fixed point computation and to keep the thing simple I chose to work only in decimal degrees rather than 3 separated numbers (degree/minute/second). The result is a limited accuracy on the calculation of very small distances and I ended up anyway with a 4 meter resolution in my garden.

The first tests were done in the village where I live just to check the distance to the chruch, then I tested the calculation on larger distances between France and California and I compared with a nice google map API that computes the real distance between 2 geo-referenced points and I got an accuracy of 2-3 km over a total trip of 8883km, less than 0.1% of error. Not bad for an embedded device :-)

Then went the time to enter the final coordinates or the e-treasure and close the box to ship it. Stressing moment. A special message is triggered if they are at more than 999 miles from the dest point and it tells them they are lost and they would better go home now. This I was able to test in my garden ^^

I don't remember how we finally decided of the spot, Oakhurst. I think Mike propose the area, being in the neighboorhood. Searching on google maps and streetview I stepped on the picture of the "oakhurst famous talking bear", a local thing to see, and I propose to use that as a DZ. Mike went there to test in situ :-)

[The box opened, it worked !]

Since it's a e-treasure, the box contained instructions printed on a sheet of paper :


If you read this, it means you successfully opened the box. I hope you didn’t use any sharp tool or hammer :-)

So you solved at least one part of the enigma : “Oakhurst & the famous Talking Bear”
To see what your gift is, you need a last effort, and complete this Web URL    
(respect the case on that part of the URL, check it’s valid before moving to the enigma)

  •   I’m famous because I can talk
  •   A smaller version of me
  •   Your cat hear it a lot
  •   10 characters dot html, no weird stuff, no space, lowevercase

If you took your laptop with you, you might give it a try around a cup of something in the local Starbuck Coffee. Also, it’s been a long ride to this place, and it was about time together. The Treasure Quest is almost over, so here’s a list of things you can do in the area :

• Yosemite
• Bass Lake
• Sierra Mono Museum
• Mono Indian Museum
• The Cunningham School
• Wassama Round House
• Fresno Flats Historic Park
• Yosemite Gallery and Indian Territory
• Little Church on the Hill
• Children's Museum Of The Sierra
• The Talking Bear
• Sierra Vista Scenic Byway
• Yosemite Gallery and Indian Territory
• Pay a visit to the 2nd most world famous talking bear living in Fresno (Gravy)

I hope you had fun during this little quest !!
See you in person soon !

with a few more clues (some of them quite disturbing, I had a lot of fun on my side *evil grin*) they quickly found the solution : littlebear.html.

CONGRATULATIONS for your wedding ! And many thanks for jumping in the game !!!!

Video of the box

►Videos of the "Quête" by Novastar & Jenstar

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