Home made security alarms

I needed to protect something temporarily one time, so I tied a section of 30lb test across the access way about a foot off the ground.
Tied one end to the fence and the other to 3lb coffee can with about 25-30 old nuts and bolts in it and set it on a cinder block back in the corner of the fenceline.

Scarred the hell out of us at 2:15 am when that can of nuts and bolts landed on the conrete. :-)

Bet whoever did it got a nice adrenaline rush too.