Geocache Stage screpter
One diamond is missing and if you find and isert it the stage begins to tell you where the next stage is (sound module). A Servo motor projects the X and RGB LEDs fade. Looks pretty cool.
https://www.youtube.com/watch?v=zJ3eF7Qx9n4
It's activated by a hall sensor and wake up code. The missing diamond has a hidden magnet.
GC50QG0