Apple, Cirque Unveil Trackball Alternative

Dave Andrews

Apple's new Mac PowerBook 500 notebooks will introduce an innovative pointing device that essentially has one moving part: your finger. Instead of rolling a ball as you would with a mouse or trackball, with Apple's new trackpad pointing device, you move your finger across a pad. The trackpad doesn't have any moving parts and doesn't require you to disassemble it to clean it. Instead of pointing and clicking, you point and tap with the trackpad.

Two layers of measurement electrodes built into the pad's surface are arranged in a check-erboard pattern that creates a series of intersections. The presence of your finger lowers the capacitance at the closest electrode intersections and modifies the signal received by the sense electrodes. The trackpad c ompares the current location of low capacitance, then compares it to the previous location, and moves the cursor accordingly. The trackpad's resolution (250 points per inch) allows cursor control down to the pixel level.

The new pointing device is not limited to PowerBooks. Cirque (Salt Lake City, UT, (801) 467-1100) says it will sell a similar device called the GlidePoint that plugs into a PS/2 port for $99. Cirque is also pursuing other manufacturers.

BYTE editors tested a preliminary version of the GlidePoint and found it should be especially useful in areas that restrict you to a limited range of motion, such as on an airplane. One potential drawback: The trackpad is so smooth that you don't get much tactile feedback. Any passive-matrix notebook, including the new PowerBooks, tends to lose the cursor when you move it quickly across the screen. With the passive-matrix/trackpad combination, you may find yourself looking up at the screen a lot more at first.

---

Photograph: Cirque's Glid ePoint brings the oldest pointing device--your finger--to PCs and notebooks. Instead of rolling a trackball or mouse, you drag your finger across the GlidePoint's motion-sensitive surface. Apple is using a similar technology in its new Mac PowerBooks.