Projects:GCSHA - SHA2017 Geo Cache

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Current status

  • So long and thanks for all the fish
  • 8-8 the cache is down. I repeat the cache is down. Still Caching anyway? [[1]] and [[2]]
  • Everything is back to normal
  • WP6 is incorrect. It should read: redacted.
  • Will be replacing it soon!
  • All beacons have been hidden. The GeoCache is now open!!!!

GCSHA2017 - The 'Official' SHA2017 unofficial GeoCache

Welcome to the SHA2017 geocache. A geocache with a techie twist. Instead of looking for physical objects, you will be looking for the SSIDs of bluetooth beacons hidden on the SHA2017 campground

Your mission

Your mission, should you choose to accept it, it to find 15 hidden bluetooth modules. Each of these bluetooth modules will give you a letter and it's relative position to the previous letter. Those 15 will form a sentense that will allow you to have some fun at the end coordinates of the geocache trail.

Geocache properties

Starting coordinates: N 52° 17.047' E 5° 31.555'

Type: Multicache Difficulty : 2.5 Terrain: 2.5 Size: Other

Other properties:

  • Fee to get in
  • Available 24/7
  • Camping
  • Parking
  • Picknick tables nearby
  • Potable water nearby
  • Public toilets nearby
  • Phones nearby
  • Requires special tools
  • <10 KM walk
  • Restaurant nearby
  • Wireless transmitter
  • Field puzzle
  • Still Hacking Anyway

What do you need?

You will need some special equipment:

  • Access to SHA2017
  • A device to get your GPS coordinates and to find other GPS coordinates
  • A device to show the SSIDs of BlueTooth Low Energy (BLE) devices around you

Luckily most smartphones actually have both properties.

Android ios Other
GPS Coordinate finder C:Geo -

Use the 'Any Destination' feature

GCTools - You can also use a dedicated GPS device
BLE scanner One of: BLE Scanner 4.0 - The badge should be able too, but you would need to write some micropython... ;) Who's up for the challenge?

How does it work

Below is an example of five waypoints. This is NOT the answer.

The first coordinate is given: N 52° 17.032' E 5° 31.521'

When you go here you open your bluetooth finder/scanner. (There is actually nothing there, this is an example.)

In the scanner you see the following SSID: GCSHA1-030-062+3S this SSID consits of 4 parts.

GCSHA1 -030 -062 +3S
GCSHA indicates that this is a GCSHA beacon

1 indicates that this is waypoint 1

N coordinate hint E coordinate hint Letter hint

In order to find waypoint 2 (WP2) you will need to add the N coordinate hint to the last three digits of the N coordinate and the E coordinate hint to the last three digits of the E coordinate.

N 52° 17.032' - 0.030' = N 52° 17.002
E  5° 31.521' - 0.062' = E  5° 31.459

You also need to place the letter in a grid of 5 letters.

. . . . .
1 2 3 4 5

+3S indicates that you have to move 3 places to the right and place the S there:

. . S . .
1 2 3 4 5

That's all the puzzling you need to do at WP1. You can now go to N 52° 17.002' E 5° 31.459' to find WP2 which reads: GCSHA2+045+016-2G

The next coordinate will thus be:

N 52° 17.002' + 0.045' = N 52° 17.047' 
E  5° 31.459' + 0.016' = E  5° 31.459'

-2G tells you to place the G two positions left of the last letter.

G . S . .
1 2 3 4 5

Now, try to solve the puzzle when I give you the last three waypoint names:

WP Name Coordinate Hint Letter hint
1 GCSHA1-030-062+3S N 52° 17.032' E 5° 31.521' +3S
2 GCSHA2+045+016-2G N 52° 17.002' E 5° 31.459' -2G
3 GCSHA3-036+036+1C
4 GCSHA4+009-048+3A
5 GCSHA5+012+058-1H
End N/A
G . S . .
1 2 3 4 5

If you added everything up the right way the end coordintate schould be the starting coordinates that the five letters should spell something familiar. ;)

O.K., let's go!!!!

O.K. you are ready to go.

Here's a form that might help you :

Final checklist:

  • Bluetooth Low Energy scanner?
  • GPS device?
  • Batteries charged?
  • Form?

Your starting coordinates are: N 52° 17.047' E 5° 31.555'

DONE! Now what ?

Come see us at Area42. Show how you solved it (E.g. by showing a filled in form File:GCSHA2017 Form v1.pdf) and you will be in for a treat.

Please also fill out the GCSHA2017 logbook.

I'm having trouble, now what?

Contact User:Seccubus via twitter [[3]] or or +31 6 438 22 637. Or find him at Village:Area42.

We have planned sessions to walk the cache together. We gather at Area42 Friday 20:00, Saturday 13:00, Sunday 13:00, Monday 13:00, Tuesday 11:00

This geocache is technology heavy. Batteries can run out, rain may soak stuff, etc. We will do our best. The current status is displayed on top of this page.


See GCSHA2017 - FAQ


Thanks for you help Big Bald Geek [[4]]