Radio Frequency Proximity Detector
Does anyone have an instructable for building a proximity detector based on a radio transmitter and receiver? Or some other wave based method? I've viewed the IR proximity detector here on this site, but I need a transmitter/receiver based one.
Yes, this is for my pet. I have 2 cats and 1 dog. I need to keep the dog out of the same areas that the cats are allowed to go into, thus the proximity detector needs to be specifically tuned to the dog. Distance does not have to be far, anywhere from several inches to a couple feet.
Appreciate any comments or instructables!