INPUT DEVICES 

An input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance

Keyboard/ keypad

• A key is made from plastic and has a small peg underneath which fits exactly into a hole in the keyboard when it is pressed 
• A small piece of rubber under the key makes it bounce back up so that it is ready to be pressed again

A keyboard is used to type characters and uses ASCII to convert = rt character into binary for the computer/ machine to process. 

How a keyboard/ keypad works: 

• When a key is pressed, the small bar under the key pushes through a small hole and makes contact with a conducting membrane

Mouse

A Mouse is an input device that uses a red LED and a sensor to determine the movement  

Trackball mouse:

It’s a mouse that’s stationery that uses a ball to move the pointer 

Pointing devices

• The most common examples are the mouse and the trackerball
• The trackerballs have a ball on top of the device by the user 
• The actual device itself remains stationary, thus requiring less desk space. 

Microphone

• When sound reaches the microphone, the diaphragm vibrates backwards and forwards
• This causes the coil to vibrate which then changes the magnetic field produced by the magnet 
• Changes in current are detected and a signal is an output 

A disadvantage of hands-free messaging- chances of messing up words/ meanings 

Input Device Functions

• Input devices transfer data from the source in the outside world to the computer
• Some data can be obtained directly through the use of sensors
• Sensors often collect data in an analog form and require conversion to digital data to be processed
• Sensors are used in both monitoring and control applications

Some do part of this automatically and these devices include:

• Scanners
• Barcode readers
• Digital cameras

Manual input devices require greater human intervention to generate the data using keypresses, mouse clicks, or a touchpad