Start 26.12.2015 - another new idea…
The cache consists of 3 holes. Behind every hole there’s a light sensor. The cacher has to flash with his torch into the holes in a given order to first to turn all LEDs on and later off. In this example two times from left (1) to right (3). This order can easily be changed inside the sketch:
Here’s a clip of the first prototype (as ever: for watching in 1080p click on the YouTibe icon):
As ever: By clicking the YouTube button, you can watch it in 1080p…
You can pick the full sketch here…