Introducing the old fashioned call for help....a loud, piercing whistle. I keep one on my wrist at all times.
Hubby found this small metal whistle on Amazon. A pack of 5, all different colors. I opted for the black for no special reason. I just did. I wear it all the time. Hanging from a ring on my watchband, I never lose it and can easily find it.
This whistle came in handy for training Noodles. It's his "come" command. He's strongly conditioned to come to me anytime he hears it. The sound travels quite a distance so I can call him just about anywhere on the farm and he comes a runnin' full speed.
My neighbor and wwoofer know that if they hear repeated short blasts on the whistle that means I'm in trouble. In all the years I've never needed to use it for an emergency. But it's good insurance to carry it on my wrist. Yes, I always have my cellphone on my too, but it's reassuring to also carry the whistle.