A direction and speed control device includes a casing, a sensing unit, and
a magnet assembly. The sensing unit includes a magnetic sensor. The magnet
assembly includes a pivot axle that is mounted rotatably on the casing and
that has a magnet carrying portion extending into the casing, and a driven
portion extending from the magnet carrying portion and disposed outwardly
of the casing, and further includes first and second magnets mounted on
the magnet carrying portion and disposed on opposite sides of the magnetic
sensor. The driven portion is operable to rotate the pivot axle relative
to the casing so as to displace the first and second magnets relative to
the magnetic sensor. The sensing unit generates a control output for
controlling direction and speed of a motor vehicle in accordance with the
displacement of the first and second magnets relative to the magnetic
sensor.