|Inside the Mind Orbit is a heavy
sintered-iron ring embedded within a plastic rotor, and a rigidly attached shaft and
magnet. When the rotor is made to spin very fast on its axis, it acts as a gyroscope, and
will resist forces that try to change the direction in which it points.
In the video clip at top left, the rotor has been spun to high rpm
by a blast of compressed air, and suspended by a string at one end. Instead of hanging
straight down, the rotor resists the pull of gravity and moves sideways. This is called
In the bottom photo the top of the housing has been
removed. The white ring fits loosely between the top and bottom housing shells, and is
free to rotate. It serves to keep the rotor centered in the housing, but does not
otherwise support the rotor shaft. The small diameter ends of the shaft rest on circular
tracks on the inside edges of the shells.
In operation, wrist motion tilts the spinning rotor by
pushing the upper and lower tracks against opposite ends of the shaft. This causes the
rotor to precess just like it does in the video clip, forcing the shaft ends to spin
faster as they roll around the tracks. By imparting a rocking motion to the housing, in
time with the precession of the rotor, the rotor can be "pumped up" to a very
Note that the magnetization direction is always parallel
to the rotor shaft, and the magnetic field is rotationally symmetrical. Thus, there is no
high speed modulation of the field.