The piezocrystal stabilizer featuring singly power supplying with low voltage, low power dissipation and low cost, is a dominant sensor for the equipment of remote-control helicopters.

The two main buttons are not physical, but instead use capacitive touch sensors with a tiny speaker to provide audible feedback for each click.

Since there was no other way out except through the doorway lined with sensors, and removing the tags could well damage the books, little choice existed.