Not how close. How fast it’s getting closer.
Most sensors react to anything nearby, which is why they’re useless on a run: everything is nearby. RunnerGuard measures closing speed instead.
When you run forward, everything standing still behind you gets farther away. A person who’s gaining on you is the rare thing that gets nearer. That difference is what the device listens for, so it stays quiet through a busy park and speaks up when it counts.
Panic buttonYes
Fall detectionYes
Warns before someone reaches youYes
Silent, so it doesn’t tip anyone offYes
No camera, no recording of peopleYes