Uncle Pete

Going to build the Ultra Sonic radar for my home. What gauge wire should I use to seperate the transducers from the board? Also, would like to hook these to an alarm system. Does anyone have an idea on that? I would be building 3 seperate radars, and would like three seperate tones, or alarms. As you can tell I am a rookie at this, but I like the challenge of new projects. Any ideas are greatly appreciated ( and needed). Thanks, Uncle Pete 8)