Page 142 - Handbook of Electronic Assistive Technology

130 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

FIGURE 5-18 Tracker Pro head-operated mouse�

There are several methods for controlling the mouse pointer on a computer, accessing
options on a communication aid of environmental control or driving a wheelchair using
head movement:
• Head or mouth stick and MouseKeys on the keyboard. This is a relatively slow method
and the user may find it hard to watch the pointer moving on screen while targeting the
keyboard with the stick.
• Head or mouth stylus with a touchscreen. This can give fast access but the screen will
have to be positioned close enough to the user’s face so that the pointer can touch it.
• Joystick operated by mouth or chin.
• Head-controlled pointing system. These are designed specifically for people with
disabilities, are easy and intuitive to use and some users find that they give accurate, fast
control. They measure the head position and/or orientation using ultrasonic, optical or
gyroscopic sensors (Figs. 5-18 and 5-19).
• Eye-gaze camera, discussed later in the chapter.

The Tracker Pro hands-free USB mouse detects the position of a reflective dot worn on eye-
glasses, a headband or a hat. The user clicks the mouse with a separate switch or Dwell Select.
The Quha Zono gyroscopic mouse detects rotation and orientation. The device is wire-
less and can be mounted on a headband, eyeglasses or neckband. It connects to computers
or tablets with USB. The user clicks the mouse with a separate switch or uses Dwell Select.

Mouse Pointer Control With Switches

The mouse pointer can also be controlled using single and multiple switches. These sys-
tems operate in a similar manner to MouseKeys – press a switch to start the pointer mov-
ing and release it to stop – and they are generally not as quick to use as mouse alternatives
such as trackballs.