Here’s an interesting DIY electric fence for keeping dogs away from cats by using IR sensors that sense when dogs come to eat cats’ lunch. Might be a good idea for some of you who might be in the same situation.
I wanted this setup to be cheap, so I decided to use an infrared “trip-wire” system. On one side of the hallway is an always-on infrared emitter, and on the other side is an infrared receiver, an AVR ATmega8 microcontroller, and a buzzer. The micocontroller continuously checks to see if the beam between the emitter and receiver has been broken – if it has, it sounds the alarm, which Riley hates, driving him away. The microcontroller is programmed so that small, fast things (such as cat tails) do not trigger the alarm. Also, the whole rig is place at Rileys shoulder height, which is much taller than the cats bodies.