I recently bought some tripwire perimeter alarms made from modified M228 grenade fuse assemblies. These are armed with common 209 shotgun primers. When the pin or cotter pin is pulled, a spring loaded striker strikes the primer. The sound is comparable to a pistol shot.
Every summer I have bears climb up on my deck (8-11 feet above ground) even though we bring in bird feeders every night. And they usually cause some damage to Mrs. Slo cat's plants.
Here are two pics of how I trip-wired my deck for bear. I placed the grenade fuse assembly where it could be easily reloaded. I strung the trip-wire about six inches away from the outside of the deck rail where it is not likely to be disturbed except for bear. I used wheels to string the trip wire at each corner of the deck as in the second pic. The trip wire extends all the way around the deck, about 45 feet, where I placed a second grenade fuse assembly. One other thing. I tested the force needed to pull the cotter pin out of the fuse assembly with my trigger test gauge. It takes 4 lbs. of pull. Since there are many birds and squirrels on my deck, I wanted a heavy enough resistance on the string to keep false alarms to a minimum. I also drilled a hole in the center of the assembly to make it easier to nail it to something solid.
Every summer I have bears climb up on my deck (8-11 feet above ground) even though we bring in bird feeders every night. And they usually cause some damage to Mrs. Slo cat's plants.
Here are two pics of how I trip-wired my deck for bear. I placed the grenade fuse assembly where it could be easily reloaded. I strung the trip-wire about six inches away from the outside of the deck rail where it is not likely to be disturbed except for bear. I used wheels to string the trip wire at each corner of the deck as in the second pic. The trip wire extends all the way around the deck, about 45 feet, where I placed a second grenade fuse assembly. One other thing. I tested the force needed to pull the cotter pin out of the fuse assembly with my trigger test gauge. It takes 4 lbs. of pull. Since there are many birds and squirrels on my deck, I wanted a heavy enough resistance on the string to keep false alarms to a minimum. I also drilled a hole in the center of the assembly to make it easier to nail it to something solid.