Ok, I gave up on the string method... the three stooges came to mind.
I did buy a new systems from Amazon / Silent call. It's basically a watch I wear at night and it receives a message when a
sensor detects sound (I set the threshold). The watch vibrates and wakes me.
So, this system is
battery operated and small. I can set the
sensor next to the
GPS and when and IF an
alarm sounds, I'll be woken via vibration. This would apply to other LOUD sounds as well.
Dual purpose is that I'll use it at home to alert me if a smoke detector activates or other LOUD
events. I can also buy separate transmitters for
phone, C02, door bell, etc, etc.
Not
cheap but I think it will do the trick.