The first thing is to know what to expect beforehand. While people think about the dollar dropping to nothing, or an Obama re-election, you need to consider the most pressing signs of a pending martial law.
Your neighborhood is now deaf, dumb, and blind.You need to buy yourself some time.Not much time, but just enough time.
And you have about 5 minutes to do it in. Maybe less.
“I took a small wall wart that is rated at 12 volts and about 100 mA. I attached it to the power and ground part of a small 12v relay I bought from radio shack. I then took a 9v battery connector and a piezeo alarm and put it on the connectors of the relay that if there is no power to the relay ~ will allow current to flow.The way you find that is to put the red wire of the connector to the relay, and one of the leads from the alarm to the opposite side of the relay. Connect the black wire and the other alarm wire together.
Provided you have a 9v battery on the connector you should hear a sound. If not, change to a different spot on the relay. So when you apply power by plugging in the wall wart, the sound goes off. Remove the wart or turn off the power, you get an alarm sound. “