sdholden

Great suggestions from both of you. Very good info so far. The linked schematic details using an induction coil which will be about as wide as a soda can and about 3 inches high. The induction coil however will only be useful within a few centimeters of the device itself, i assume because the coil is sensing the EM field. I also found a very good project kit through searching for "cell phone remote control", but this kit actually uses a light sensor to detect the backlight of the phone when it comes on. Thus the phone must be in very close proximity to the unit. Are these the only ways? Is there not a way to "sense" the incoming call? I.e. by receiving the signal itself? This would be much more effective and come in a smaller package. Thanks.

For my current project, I need the ability to detect an incoming cellular phone call, (850 mhz - 1200 mhz). When this signal is present, a switch will be thrown to enable desired operation. I've been searching for this kind of component and just haven't found it. Doesn't necessarily have to be a sensing switch, just something that gives a state change on reception so I can wire in and use for the switch actuator. Thanks.