Input received operation Keyboard Keyboard SystemKeyboard CPU controller Buffer Software 1. Press key 2. A chip (k.C) notes that a key has been pressed 3. K.C has K.B 4. K.C places a code of pressed key in this buffer. 5. K.C indicates S.S that something has happened by sending a signal to it. 6. S.S determine appropriate response. 7. The system reads the code of the pressed key from the keyboard buffer and sends that code to the CPU.
2. MOUSE• Used to: select menu, access menu & interact with programmes.
Mechanical Mouse • Moving the mouse turns the ball • X and Y rollers grip the ball & transfer movement. • Inside sensors send signals to the computer which tell it the distance, direction & Speed of the ball’s motions.
Optical Mouse • Non mechanical mouse • Emits beam and lights from underside • Use LED • Light reflection is used to judge the distance, direction & speed.f
Usage Benefits• Clicking Cursor movement• Double clicking Selecting position• Dragging Button usage determined• Right clicking by: • Os • Application Software • System Software
10. Scanners 1. doc/photograph is mounted on a rotating drum. 2. Light beam is directed at the pic and the amount of light reflected is measured by photocell. 3. Drum rotates, the light source moves from one end to the other. Types: 1. Flatbed scanner 2. Sheet fed scanner 3. Hand held scanner 4. Drum scanner.