I'm thinking about alarm/security systems that don't rely on power. My thoughts are that as we descend to third world status we will begin to experience periodic power outages. I'm reminded of a backpacking trip I took in 1980 to Nepal. While I was in Kathmandu there would be brownouts and periodic outages every evening as demand for power would exceed supply. Dogs are an obvious answer, but I have also read about geese being used as alarms by Romans and others. Geese also have an advantage of also being a source of protein. I'm interested in your thoughts of dogs, geese, and other critters that might be useful as well as having a secondary purpose.