Adjustable Signal...radio, bluetooth, etc.
I am trying to figure out how to control a device that will be "off" while in the range of a transmitter (short range...under 10ft) and then turn on when it goes beyond the range of the signal. I would also like it to be an adjustable range. I was thinking the device would be "on" constantly as the transmitter tells it not to activate, but once it leaves the signal range it would activate.
Thank you in advance.