Input Devices

• Touchscreens can be used as both input and output devices.
• Barcodes are a unique series of lines representing the numbers 0 to 9. They are read by a red LED scanner, which reads reflected light to create a digital sequence which can be turned into binary.
• Barcodes are mainly used in supermarkets. Barcode data is stored in a database as a key field to retrieve other details about the product
• Barcodes are easier and faster to use and allow for automatic stock control. It also allows faster checkout queues and better tracking of sell by dates
• QR Codes are made up from a matrix of black and white squares. Large squares at the corners are used to align the code whilst scanning
• QR codes can be used to advertise products, give automatic website access, store boarding passes and are read by cameras on a smartphone or tablet
• QR codes hold more information than a barcode, can be encrypted and contain error checks. They also are easy to read and don’t require expensive equipment
• However, QR codes can be used to transmit malicious code, known as attagging. It is easy for criminals to write malicious code and embed it into a QR code
• Digital Cameras: A device that captures images and stores them in a digital format. Microprocessors in the cameras control the shutter and lens. Small cameras can be used as parking aids, in drones or in endoscopes
• 2D Scanners: Scan documents and convert them into electronic files. Can scan both text and graphics. Optical character recognition (OCR) technology converts printed characters into editable text. Used in airports to scan passports to enable facial recognition
• Keyboards: A keyboard is a device that allows a user to enter text or data into a computer. Each character on a keyboard has an ASCII value which allows the computer to register what was typed. Data entry via a keyboard is slow, prone to error and can lead to RSI
• Microphones: A device that converts sound waves into electrical currents of varying amplitude using a diaphragm and a copper coil and a cone attached to it . This can be converted into digital data as vibrations create an electrical current as the coil vibrates.
• Optical Mouse: Used to move an onscreen cursor. An example of a pointing device. Uses tiny cameras and an LED to calculate the exact position of the mouse.
• Advantages of an Optical Mouse:

  No moving parts, so more reliable

  Dirt cannot get trapped in its components

  No need for special software
• Advantages of a wired (USB) mouse:

  Wired connections have no signal loss

  Cheaper to use, no batteries needed

  Fewer environmental issues, no disposal of batteries
• 3D Scanners: Scan solid objects to produce a 3D image to be used in computer aided design or sent to a 3D printer. Uses lasers, X-rays, or ultrasound. Used in medical settings in tomography which is producing a digital image of the body.
• Capacitive Touchscreens: A touchscreen that uses a layer of conductive material to detect the presence of a finger which changes the electrostatic field which is detected by a microprocessor. Durable screens, good clarity in all lightings but sensitive to microwaves
• Infrared Touchscreens: Uses an array of sensors and infrared transmitters which detect when a beam is broken by a finger and the position of the finger is calculated by a microprocesso. Not affected by scratches or cracks, sensitive to moisture and light interference
• Resistive Touchscreens: Uses two layers of conductive materials with a spacer between them. When pressed together they form a circuit at the point where the pressure was applied. Can be damaged easily, not very durable, cheapest type of screen