Optical Mouse

Mice: How Do They Work?

Open up a mouse and inside it we will find two wheels, each one similar to the first drawing. The wheel is usually made of black plastic with rectangular slots punched in it. I have shown only 6 slots at 60° spacing but they are a lot closer and many more. Shining through the slots are two LEDs (light Emitting Diodes) shown by the black dots. Each LED shines on to a light sensitive transistor. The two emitters are spaced so that, when one transistor can 'see' its LED through the centre of its window, the other LED is looking at an edge and is therefore switching on or off.

Inside An Optical Mouse

If we take apart an optical mouse and look inside, we will find a complete imaging system. The mouse is essentially a tiny, high-speed video camera and image processor. As shown in figure below, a light-emitting diode (LED) illuminates the surface underneath the mouse. The light from the LED reflects off microscopic textural features in the area. A plastic lens collects the reflected light and forms an image on a sensor. If we were to look at the image, it would be a black-and-white picture of a tiny section of the surface. The sensor continuously takes pictures as the mouse moves. The sensor takes pictures quickly-1500 pictures (frames) per second or more fast enough so that sequential pictures overlap. The images are then sent to the optical navigation engine for processing.

Increased accuracy

Due to the limits of existing optical mouse technology, the cursor does not always land where you want it. This causes reduced accuracy and increased frustration.  Optical Technology provides superior accuracy and enables the cursor to land where you want it.

Abstract

Every day of our computing life, we reach out for our mouse whenever we want to move our cursor or activate something. Our mouse senses our motion and our clicks and sends them to the computer so that it can respond appropriately. It is amazing how simple and effective a mouse is, and it is also amazing how long it took Mice to become a part of everyday life. Given that people naturally point at things -- usually before they speak -- it is surprising that it took so long for a good pointing device to develop. Although originally conceived in the 1960s, it took quite some time for mice to become mainstream. In the beginning there was no need to point because computers used crude interfaces like teletype machines or punch cards for data entry.

Introduction

It is amazing how simple and effective a mouse is, and it is also amazing how long it took mice to become a part of everyday life. Given that people naturally point at things -- usually before they speak -- it is surprising that it took so long for a good pointing device to develop. Although originally conceived in the 1960s, it took quite some time for mice to become mainstream.

In the beginning there was no need to point because computers used crude interfaces like Teletype machines or punch cards for data entry before arrow keys were found on most terminals. Full screen editors were the first things to take real advantage of the cursor keys, and they offered humans the first crude way to point.

Conclusion

The optical sensor performs best on surfaces with detail to track. It will not function on surfaces without visible detail (such as glass) or surfaces on which it has a reflection (such as mirrors or glossy surfaces). The optical sensor may also have difficulty tracking on highly repetitive patterns.