| How does a scanner work? | Document is placed in a glass panel
A bright xenon light is flashed onto the document capturing the reflected light
The scan head moves across the document capturing the reflected light
A grid of light sensors converts the image to an electrical form
From this the software creates a digital image |
| How does a barcode reader work ? | A LED or laser red light is flashed onto the barcode
The reflected light is captured by light sensors
Dark lines reflect less light that light lines
By measuring the amount of light reflected a pattern can be deduced
The code is identified |
| How does a mechanical mouse work? | A ball rotates when the mouse is moved across a solid surface, sensors detect the direction in which the ball rotates |
| How does a optical mouse work ? | A LED light is flashed on to the surface, the reflected image of the surface is compared with the previous image to detect the direction of movement |
| How do printers work? | The data from the document is sent to a printer driver
The printer driver ensures that the data is in a format that the chosen printer can understand
A check is made by the printer driver to ensure the printer is ready to print (Is it busy, Is it out of ink, ETC)
The data is sent to the printer and stored in a temporary memory known as printer buffer
A sheet of paper is then fed into the main body of the printer, a sensor detects if paper is available in the feed tray, if not a an error message is sent to the computer
Once the printer buffer is empty, the printer sends an interrupt to the processor in the computer this is a request for more data to be sent yo the printer , the whole process is repeated until the whole document has been printed |
| How do speakers work? | The sound is played in a digital playback device
The binary signal is produced
This signal is sent to digital to a analog converter
This translates the signal into analog
This signal is sent to the amplifier
The amplifier signal is sent to the speaker which produces the sound |
| How do digital light projectors work? | A xenon light is sent through a color filter which splits the light into RGB, these are directed towards towards a large number of micromirrors
Each mirror tilts at different speeds, this results in different shades of RGB produced |
