The mouse is a pointing device generally made of plastic.
It is used by one of the hands of the computer user and it detects this hand’s movement in two dimensions on the level surface the mouse is on.
This movement is then reflected on the screen with an arrow or pointer.
It can work on almost any surface. It has a small red diode than bounces the light from a surface onto a CMOS sensor (complimentary metal-oxide semiconductor). The CMOS sensor sends every image to a DSP processor (Digital Signal Processor) to be analysed. The DSP, operating at 18MIPS (millions of instructiosn per second) can detect forms in these images and can see how these forms have moved between images. Based on the changes seen in a sequence of images the DSP works out how the mouse has moved and it sends the corresponding coordinates to the computer.
Printers are peripherals that allow us to print text and images from a digital archive.
The quality of a printer depends on:
The resolution or number of dots an inch that the machines prints.
The speed of the printing that is measured in pages per minute.
Printers are normally connected to the USB port.
Types of printer
Inkjet printer. These printers print using one or various ink cartridges that contain between 3 and 30 ml. Some print in very high quality, almost as good a quality as the Laser printers. See photo on the left.
These are the best quality printers and their prices vary widely, depending on the model.I They are the method of printing used in printing presses and they work in a similar way to photocopiers.
The quality of the printing and the speed of laser printers is really surprising.
Plotter. These printers are specialized in vector drawings and very common in architects studios. See photo on the left.
This is the process used to copy a document:
Light up the image with a spotlight. The light reflected off the object is directed, using mirrors, to the CCD device, which converts it into electronic signals. Then these signals are converted to a digital format thanks to a analog-digital converter that transmits the subsequent flow of bits to the computer.
The CCD is the most important element of a scanner. it is an electrical component that reacts to light. It transmits more or less electricity depending on the intensity and colour of the light.
It’s like an electronic eye and it is also used in other devices, like cameras and videos. The quality of the scanning depends on the refinement of the CCD; the analog-digital converter and adequate cleaning.
The software is the programmes, like the operating system, the text processors, video games, internet navigators etc.
The best way to learn is to practise with them. We will practise with OpenOffice.