Design to turn a cheap Chinese "Personal Safety Alarm" into a trip wire perimeter alarm.
Link to device: https://a.co/d/5HNMNvt (Less than $10 for 3). These device will produce a very loud alarm if the “trigger/key” is pulled out of the main body.
Use this for camping to ensure that I know if someone or something (bear) approaches my camp site. The loudness alone can scare threat away. Great for go-bag, camping, add a theft deterrent to area or objects.


For storage/travel, put the trigger lock into the end slot as show in pictures. Then snap the “Personal Safety Alarm”, curved end first and over the trigger lock.
For alarm, remove the trigger lock then insert the device as above. Attach mount to tree, wall or whatever. Then attach a trip wire to the trigger loop on the device and tie the other end as necessary. Can test if you wish.
The author marked this model as their own original creation.