On Fri, 07 May 2010 16:40:32 -0400, Tony wrote:
wrote:

I've seen plenty of remote controls that had to be replaced because
they would intermittantly start transmitting random signals without
being touched.

On a very old TV, with a remote control (a motor to change the channels,
ca chunk, ca chunk). It started going on and off and changing channels

I've looked inside those remote controls, they would bang a short
piece of metal that worked like a tuning fork to generate the
ultrasonic frequencies. Later in the late 70's, a grandmother had a
tv with a solid state version that drove an ultrasonic transducer.