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5th JC Simon Says

5th Joint-US-GE-Cache „Simon Says“ (German version: GC6A25K) 

You told me that you like to work on a Simon-Says… Ok, so we’ll do it. There’re already of thoose caches existing, so we should make it unique. At the moment I don’t have a great idea, but one thing is clear: I fully support your view not show show a code at the end but to unlock a door mechanically by the Arduino. Even this part will be a joint one, because it will your turn to have a clever idea for the mechanics, while I’m doing the programming (I started alredy reading the regarding chapter of the „Arduino Cookbook“. It shouldn’t be too difficult…).

But the mechanics are still a miracle for me. Why? Let me explaining step by step:

  1. The door is closed by a kind of latch mounted to a servo motor. The latch is behind another one, so the door is closed.
  2. Opening the door means, the servo will turn the latch by e.g. 90° and the chacher can open the door.


Up to this stage it’s quite easy. But how to close the door?

  1. Like opening, but the other way round: Close the door and turn the latch back: 
    1. But how to ensure, the cacher will close the door?
    2. How to discover he has done it and than turning the servo?
  2. The mechanics are a kind of spring. So just after opening the door, the servo will turn back to close position. Closing the door can be done, even when the servo is in „locked“ position-
    1. In principle this solution should be the preffered one.
    2. But how to realize? I have no idea! 


Monday, 9.11.2015: Prototype running!

Being back from the island on Monday noon first I made bug-fixing on the GPS cache. I hope, it’s working now. Hoping because I can’t validate without hardware available.

After that I worked on the "Simon Says“. Here’s the result after less than 90 minutes of wiring:

As ever: By clicking the YouTube button, you can watch it in 1080p…


I’ll put the sketch into our shared DropBox. The coding is quite „spaghetti“, but I think, I’ve found the line from which we’ll jump to the door-opening-subroutine…

I was just thinking about the mechanism for the door lock. Even if that’s your part, what do you think about this?

Door Lock



Monday, 25.01.2016 - I’ve just finished my German version

Different to Tim I decided to put the cache into an Ammo cam to hide it somewhere in the woods. First approach of a weather protection didn’t fit into the housing...

IMG 1436


Maybe more interesting: I optimized the sketch. Now the cacher is starting with level 10. This means a series of 10 buttons to be pressed. After failing, the level is decreased by one up to level 5, which should be „doable“ for everyone…



Friday, 11.3.2016 - really ready...

I’ve worked a lot on other things during the last weeks, but this weekend I’ll place the cache and send the listing for review. 

IMG 1437



Saturday, 19.3.2016 - Published - Found - 1st Maintenance

Hans-Grete (Tina) published the cache at 10:00 am this morning and quite soon I received a call from Monique & Andy. They tried already 3 batteries, but nothing was happening. Also the lock of the chain couldn’t be opened. I took some stuff with me and met them at the cache. The lock is really not opening with the correct figures. Shit! It’s quite probable, I mixed it up.

I opened the cache and everything looked fine. Monique & Andy were happy to have this „view inside“, which no-one usually will have. Andy is very well equipped. Even he had a multimeter with him! So we discovered a problem with the case for the 9V batterie. After a little bending, everything was working fine and Monique started to solve the game. Meanwhile a second cacher couple arrived. After totally being sure, everything working, I left for preparing the lunch...


You can pick the full sketch here




©  Olaf Goette 2008 - 2022