Loud Vibrating Alarm Clocks Deaf Clocks Silent Bed Shakers A knock sensor is a crucial component in modern engines that helps prevent engine damage. It's essentially an electronic "ear" that listens to the engine for abnormal vibrations and sounds. How does Is there a way to still get notifications but with no noise? Without having my phone on silent? My dogs react more to the ring noise on my phone than they do Put Your iPhone in Ring or Silent Mode