A data recording disk drive has one or more capacitive sensors for sensing
out-of-plane vibration of the disk or disks. The sensors are attached to
a support structure that is attached to the disk drive housing. Each
sensor is associated with a disk and faces a surface of the disk near the
outer perimeter of the disk and close to the recording head. The support
structure can be made of a metal or a high-strength plastic and can be a
separate structure mounted to the housing, or integrated as part of the
single-piece housing casting. If it is metallic, as would be the case if
it were integrated with the housing, then layers of insulating material
separate the sensors from the support structure. A support structure that
serves other functions in the disk drive can also function as the support
structure for the capacitive sensors.