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Input devices (Manual Input Devices (Key boards and key pads :keyboard:,…
Input devices
Manual Input Devices
Key boards and key pads
:keyboard:
pointing devices
:mouse: :three_button_mouse: such as the mouse and the tracker ball (a ball is moved by the user, but the device stays stationary, thus taking up less desk space).
Touchscreens
:male-technologist: in tablets, watches and mobile phones.
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Bar-code Readers
UPC-A
(universal code product versions 'A') used in retail and warehouse. It only has numbers.
Code 128
used in transport and shipping packages. It represents both letters and numbers.
How do barcode readers work?
The reflected red light is picked up by sensors in the barcode reader in the form of lights or darks or 1's and 0's (binary!). This is sent to the decoder which interprets that signal, validates the barcode using the check digit, and converts it into text.
The 4 types of barcode readers to know
Pen type readers
:fountain_pen:: A light source a photo diode on the tip of a pen which is dragged across the bar. The photo diode measures the intensity of the light reflected back from the light source to generate a wave front. The width of the bars and spaces are measured.
Pros:
Are durable, and can be kept safe from environment hazards and dirt. Lightweight and portable so are ideal for low volume scanning applications and computers.
Cons:
Their applications are limited because they must come in direct contact wit the barcode to read it.
Laser Scanners
:shopping_trolley::They use laser beams as alight source. The photo diode measures the intensity of the light reflected back from the light source to generate a wave front. The width of the bars and spaces are measured. You can spot these in supermarkets.
Pros:
Reliable and economical for low-volume applications. Can be used with 2D and 3D surfaces.
Cons:
some systems don't work in the sun or rain. Hardware is expensive.
Sensors are hardware devices that can take measurements of physical properties.
Data taken form sensors is usually in analogue form.
In
monitoring
, the computer or process will report the values unchanged.
In
control
the computer or processor output can alter how the process is operating, so the output can affect the next input it receives. For example, it can change values such as switch the heating off.
detection or monitoring systems
:Pressure sensors, acoustic sensors and infrared sensors (for movement or change in heat) are all examples of detection sensors. Monitoring sensors constantly monitor rooms for intruder and data is converted into digital form using an ADC and is sent to the microprocessor.
QR codes
QR codes
are 2D barcodes that can be read by smartphones or tablets.
You can use QR codes for links to websites, information, restaurant coupons, mobile concert tickets, real estate agency boards, business cards, tourist information, advertising posters.
Open the QR reader on your phone and hover the device over the code so that it is clearly visible on your smartphone or tablets screen, the phone will automatically scan the code or in some cases you will have to press a button to snap a picture.
More Devices
Interactive white boards
:white_large_square: :raising_hand: Used to show audiences or students computer outputs. they allow written annotations by hand which can be saved and used for later.
2D scanners
to convert hard copy documents into a computer readable format.for emailing images, art or text to someone else.
Devices that transfer data fro the outside world into the computer.
