Accelerometer vibrations pick=up

摘要

The accelerometer (1) is encased in a rubber sheath (2) which is mounted on a pad (3) of open celled foam. The pad (3) is attached to an elastic membrane (4) which is shaped like a bowl and has a rim which locates it within a cavity (6) in a foam sheet (5).The accelerometer (1) is held slightly outside the open side of the bowl shaped membrane by the pad (3) such that it is pressed against the head when the helmet is worn. The membrane (4) has holes (7) which equalise air pressure on each of it's sides.