Optical Mouse

The first computer mouse which was provided with the purchase of a computer was available in 1981. This however was a standard ball mouse; the photograph above shows an optical mouse. Whilst optical mice were in development at around the same time they would not become wide spread until much later. Modern optical mice such as the one in my photograph use optoelectronic sensors which take continuous pictures of the surface which the mouse is on.

The mice include within them an image processing chip this enables the mouse to detect relative movement on many different surfaces. The reason that the mice glow red is because the area under which the optoelectronic sensors operate needs to be illuminated. This illumination is provided by an LED, although interestingly the only reason red light is used is tradition most other colours would work just as well. The only reason red is used is at the time when optical mouse's were first developed red LED's were the cheapest to produce.