How can we build a cheap detector that senses a cellular (electromagnetic?) for use as a switch for a computer?
we want to use a cellular phone as a "switch" to control a multimedia show.
We thought of a cheap sensor that must be able to detect electromagnetic waves through a store window. We thought of phones because everyone has one in they pocket, phone is simply the source of the field.
Idea is that customers can move their mobile phones in front of our store window to control a multimedia show in a simple way (forward, backward, pause), so in the end three or four different switches glued to the window would perform as a "control pad" for the computer.
Maybe there is a way to base this project on products readily available which can be remodeled.
Thanks for sour suppport and ideas!