Hiding sensors

Finally we used five proximity sensors for each object. Can you find sensors in the seeting pictures? I saw many people who wanted to find sensors that trigger the movements of objects.
We tried to hide sensors people not to fine them easily.
But here, I open the secret!

This one is for a bag.


This one is for a book.


This one is for pencils.


This one is for a cup.


And we hided a sensor for a box in the book.