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Optical Mice Tutorial
An optical mouse uses a tiny camera to take approximately 1,500 pictures
every second. The pictures are taken by bouncing light from a small,
red light-emitting diode (LED) off the surface under the mouse, and
onto a complimentary metal-oxide semiconductor (CMOS) sensor. The CMOS
sensor sends each image to a digital signal processor (DSP) for analysis.
The DSP, operating at 18 MIPS (million instructions per second), is
able to detect the changing patterns in the images between movements.
Based on these patterns, the DSP determines how far the mouse has moved
and sends the corresponding coordinates to the computer. The computer
moves the cursor on the screen based on the coordinates received. Since
this happens hundreds of times each second, the cursor appears to move
very smoothly. Optical mice usually have an option for more than the usual 2 buttons
on the top of the mouse surface. Additional buttons are, for the most
part, programmable by the user.
Terminology
LED - a display technology that uses a semiconductor diode
that emits light when charged. LEDs are used in readouts and
on/off lights in a myriad of electronic appliances and as a
light source for fiber-optic transmission. CMOS - a type of integrated circuit for digital processors
and memories. CMOS uses PMOS (Positive channel) and NMOS (N-channel)
transistors wired together in a way that uses less power than
PMOS-only or NMOS-only circuits. DSP - a specialized microprocessor that performs mathematical operations
on a data stream in real time to produce a second (modified) data
stream.
Benefits of optical technology
-The lack of moving parts decreases the chance of a failure Agilent Optical Mouse Sensor (ADNS-2001)
Companies using Optical Mice
8/15/01 |
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