Mobile phone screamer?
Has anyone got a schematic or instructions for making a noise generator I can attach to my cell phone through the mike/earphone jack? I am getting a lot of "junk" calls with faked return numbers, who will not remove me from their call lists and typically call 3-5 times a day, even at night. My provider (AllTel) says there's nothing they can do to help me block calls with bogus or "unavailable" return numbers.
OK, I admit this is more for my own sense of justice than anything else, but I'd sure like to have some sort of oscillator that would generate enough volume at a high pitch to at least give them a nice headache.