Finding, Installing, and Using a Trackball

Trackballs are really upside-down, roller-bearing mouse devices. Instead of the ball being inside the body, the ball is on the outside of a trackball and you move just the ball instead of the mouse body. Trackballs have several advantages over mouse devices. Because you don't actually move the trackball itself, it takes up less space than a mouse does. And you don't have to lift it up to move it when you run out of room or reach. Because your hand remains stationary, you don't rub the sensitive areas of your wrist across the edge of your desk, which can lead to damage of the tissues in your forearm. Trackballs also have more than one button, and you can program the other buttons to perform various functions. For example, you can set a button to add a modifier key to the click so you can bring up contextual menus with a click instead of having to hold down the Control key while you click a standard one-button mouse. In addition, trackballs can move the cursor either more quickly to cover more screen real estate or more slowly to give you more precise control than a mouse.

Choosing a trackball is similar to choosing a keyboard or mouse (except that desktop Macs don't ship with a default trackball). Look for one that fits your hand and has the features you wantsuch as the number of buttons it has.

NOTE

Another great input device manufacturer is Kensington. You can learn more about Kensington input devices at www.kensington.com.

Installing trackballs is also similar to installing keyboards and mouse devices. You attach the device through an available USB port and then install and configure its software. Some of these devices are wireless and are set up similarly to wireless keyboards and mouse devices.

CAUTION

If you experience fatigue or pain when using any input device, make sure that you experiment to see whether you can find a more comfortable position for the device. If you can't, consider replacing the device with another type that is more suited to you. Discomfort, even of a mild nature, can indicate that some damage is being done to your body. If this happens over a long period of time, you can end up with serious health problems.

If you do experience problems, consider obtaining several different devices and set up positions among which you can rotate so you can avoid repeating exactly the same actions over an extended period of time. For example, you might want to have both a mouse and a trackball and switch between those devices every so often.

Providing Universal Access

You can use the Universal Access pane of the System Preferences application to configure input devices in different ways to enable those with disabilities to be better able to use a Mac. For example, you can use the Sticky Key feature to cause a series of modifier key presses (such as or Option) to be treated like those keys are pressed at the same time. You can also use Mouse Keys to enable the pointer to be moved with the keyboard for folks who have difficulties using a mouse.

For the details of configuring Universal Access, p. 261.