Alternative Mice
The standard computer mouse is generally used by moving the mouse on a surface, usually a mouse mat, which in turn moves the cursor on the computer screen. Selections are made using click and drag buttons on the mouse. For some people, a standard mouse can be difficult or impossible to use but there are now a considerable number of alternatives to the standard mouse (also known as alternative pointing devices) which include trackball, joystick, touchpad, headmouse, touchscreen and eyegaze.
A trackball is essentially an upside down mouse. The cursor is controlled by the user moving a ball located on the upper surface of the trackball. Consequently, the mouse itself does not move on the surface of the table and there is no need for a mouse mat. The user selects items by using the 'click' button on the trackball.
A joystick mouse allows the user to control the cursor on screen by moving a joystick in any of four directions: up, down, right, left, as well as all directions in between. The user may select items by using the 'click' button on the joystick.
Touchpads are pointing devices, or mice commonly used in laptops. A touchpad is a flat surface on which the user moves his/her finger in order to control the cursor. The user can select by either tapping quickly on the touchpad (for a double-click) or by using the standard mouse buttons. Many laptops have built-in touchpads instead of standard mice. A separate one can be purchased for use with a desktop computer.
A headmouse can be operated through the use of a reflective dot being placed on the user's forehead/bridge of their glasses. When the user moves his/her head, the movement of the headmouse is recognised by an infrared receiver (camera placed on top of the computer screen) which in turn translates the head movements into cursor movements on screen. Mouse selections are made either using a dwell facility whereby the user pauses on the on-screen target for an agreed period, at the end of which, a selection is made, or alternatively, using an external switch (internal link to switches above). A headmouse is often used with an onscreen keyboard.
A footmouse allows hands-free mouse operations using one foot or both feet as an alternative to using a standard hand-controlled mouse. All standard mouse operations such as single and double click, drag, cut and paste, etc can be controlled using foot movements instead.
Touchscreen
A touchscreen is a computer monitor with a touch sensitive overlay. When the user touches the screen, the mouse cursor moves to that location. Selections can be made by either tapping the screen or dwelling on a location.
Eyegaze
Eyegaze is the most recent technological advancement for access to computer and communication devices, and allows those who experience difficulty in controlling the mouse by other means to access software. Eyegaze works by using infrared beams to identify the user's pupils, and a camera to track the movements of the eyes around the screen. Dwelling on an item, blinking or using an external switch is used to select an item.
