Computer Input

"Input" is when data from the outside world which is made digital and entered into a computer. Images into a camera, sound into a microphone, text into a keyboard, or movement and clicks into a mouse or trackpad—all of this is real-world information input into a computer. This chapter covers the various types of input devices, including ways to use them.

  • There are various types of keyboards, and different key layouts according to language and country
  • The mouse is a traditional control device with two or more buttons, which now use lasers
  • Trackballs are modified mice with a ball on top to control the cursor movement
  • Trackpads are flat surfaces, usually on laptops, which allow for multitouch control of the cursor and button actions
  • Mobile devices have touch-sensitive screens for control similar to trackpads
  • Cameras and microphones (for example, as webcams) allow for image, audio, and video input and control
  • Scanners allow images on flat surfaces (usually photos, text, or codes on paper, or film negatives) to be input
  • Motion sensors allow hand and body movement to act as input


The keyboard is the oldest type of input still commonly used. Almost everybody has experience using a keyboard.

There are two basic types of keyboards: standard and extended. Standard keyboards have the normal character keys (A-Z, 1-0), modifier keys (control, alt, escape, etc.), and function keys. An extended keyboard also includes navigation keys (arrows, page up/down, etc.) and a numeric keypad, a set of keys with numbers and mathematical keys for quick number entry and calculations.

An extended keyboard layout

One problem associated with keyboards is "carpal tunnel syndrome," a wrist injury from typing too much. One way to avoid this injury is by using a type of keyboard called ergonomic, designed to fit the natural position of the arms and hands.

There are even some devices which use a laser to project the image of a keyboard on a surface, and then record where your fingers move to decide which "keys" are being "pressed."

An ergonomic keyboard A laser keyboard

As described in the "Legacy" feature above, the most common keyboard layout is the "QWERTY" layout. However, it is not the only one.

If you live in Japan, for example, you may have experience with the slight differences between the Japanese (JIS) keyboard layout and the standard QWERTY. For example, the "@" mark and the "+" sign are in very different locations. Below are the two layouts, side by side.

The QWERTY keyboard layout The JIS keyboard layout

In the above layouts, you can see rather major differences between the physical keys. However, many layouts use the same physical keys—and by accessing the operating system controls (in the Control Panel or System Preferences), you can change the layout of your keyboard.

Below, for example, you can see the standard U.S. keyboard, and the special "DVORAK" keyboard, side by side. The DVORAK layout is designed for fast touch-typing. Because the same physical keys are used, a computer with a standard U.S. keyboard can switch rather easily between them.

The QWERTY keyboard layout The DVORAK keyboard layout

Try For Yourself

You can change the keyboard layout or the language of input on your computer!

To change keyboards in Windows 7:

  1. Go to the Control Panel;
  2. Open the "Region and Language" dialog (you can search for it in the upper-right corner);
  3. Click on the "Keyboards and Languages" tab at the top;
  4. Click on the "Change Keyboards" button;
  5. You will see the "Text Services and Input Languages" dialog;
  6. In the bottom half, there is a list of keyboards; click the "Add" button to the right of that;
  7. In the new dialog box, you can choose whatever keyboard layout you wish. The DVORAK layout is under "English (United States)," "Keyboard," and "United States-Dvorak";
  8. Check the keyboard(s) you want to add;
  9. Click "OK" on all the dialogs to set the changes and close them.
  10. You will see a Keyboard icon in the System Tray (bottom right of the screen). Click on that and choose your keyboard.

To change keyboards in Mac OS X:

  1. Go to the System Preferences;
  2. Open "Language and Text";
  3. Click on "Input Sources" at the top right;
  4. Check the layouts you want from the menu on the left;
  5. Make sure "Show Input menu in menu bar" is checked;
  6. Close the System Preferences;
  7. In the Menu bar, at the top right, you will see a flag icon. Click on the flag icon to select the layout you will use.

Cursor Control Devices


a picture of the first mouse
The first mouse, ca. 1970

The mouse was invented in the 1960's by Douglas Engelbart and his team at SRI (Stanford Research Institute). It was part of a larger project which also gave birth to the GUI (Graphic User Interface), and included features we now see as normal—hyperlinks, copy and paste, video conferencing, windows, and more.

The mouse is essentially a control device, allowing the user to point an arrow, or cursor, at any part of a screen, and then manipulate items on the screen through various "clicks" (pressing buttons).

a picture of a multi-button (gaming) mouse
A gaming mouse

Today, a standard mouse has two main buttons as well as a scroll wheel, which can be both rolled and clicked. Here are the main functions of a mouse:

  • Movement: Controls cursor position
  • Left-click: Select
  • Left-double-click: Open
  • Right-click: Open floating ("pop-up") menu
  • Scroll wheel: Scroll up and down
  • Scroll wheel click: Various functions (back, close, zoom, etc.) depending on where you click. For example, a scroll-click will close a browser tab.

You can change the settings for a mouse by going to Control Panels / System Preferences and choosing "Mouse." If you buy a special multi-button mouse, you can program each button to perform different actions, such as opening programs, changing system settings, and more. An example of such a mouse is pictured at right.

Mouse actions can be combined for extra functionality. For example, you can click a button while moving the mouse, as in the click-and-drag operation. You can also combine a mouse action with a keyboard action, such as in the Control+click operation (to select multiple items).


a picture of a trackball
A Trackball

A trackball is a mouse-like device where you control the cursor using a ball, instead of moving the device itself around. This avoids problems such as running out of room for the mouse to travel. A common trackball is pictured at right.


a picture of a trackpad on an Apple Macbook pro
A laptop trackpad

A trackpad is a touch-sensitive surface, usually a small rectangle, located below a keyboard on a laptop computer. This works instead of a mouse, allowing finger movements to control the cursor. When you move a finger across the surface of the trackpad, this is often called a swipe.

The trackpad usually includes buttons just as a mouse does, though in the illustration at right (of a Macintosh trackpad), the whole surface is a button. Furthermore, the trackpad can be set so that finger taps can be used instead of button clicks. For example, you can tap-and-swipe instead of click-and-drag.

Many trackpads today are Multitouch, meaning that the computer can "see" more than one finger. This allows you to perform a large number of special actions using the trackpad. The most common action is the two-finger scroll (please try it if you have a trackpad), where you swipe two fingers up or down to scroll on a page or in a window. These special actions are often called gestures.

An example of several gestures on a Mac OS X trackpad:

  • Two-finger tap: equals the right-click on a mouse
  • Three-finger tap: look up a word in the dictionary
  • Two-finger circular swipe: rotate
  • Two-finger pinch in or out: zoom in or out
  • Three-finger swipe: drag a window from any point
  • Four-finger spread-swipe outwards: show the Desktop
  • Four-finger spread-swipe inwards: show the App Launcher
  • Four-finger upwards swipe: show all open apps and windows

Newer computers and more recent operating systems are more likely to include multitouch gestures.

Audio / Video Input


an example of multitouch
Multi-touch on a Tablet
The app you see in the image is Tesla Toy ($2) in iOS. A similar app is Sparkle Toy ($1) for Android.

Touchscreens work just like trackpads, except they are also monitors. Most handheld devices have multitouch ability, but many touchscreen monitors only will sense one or two fingers. Sometimes it is necessary to read the specifications of the monitor carefully in order to understand the screen's features.


Many computers have cameras (often called webcams) built into the monitor, especially laptops. Computers without built-in cameras can use a peripheral camera connected by a USB cable, often for only $10 or $20.

These cameras can take photos, but usually are for video conferencing, using applications like Skype, or the video chat feature built into Google Mail.

Handheld devices are usually equipped with a camera (which is not called a webcam), which is used much more for photography and taking videos. These cameras are often much higher quality than an average webcam. Handheld device cameras can be 12 megapixels or more, and can take full-HD video, recently even at 60 frames per second for slow-motion video.


Microphones are built into most handheld and laptop devices, as well as some desktop computers. Computers without microphones can accept peripherals (using either an audio jack or USB), or can use a microphone which is part of a headset.

Speech recognition is becoming more and more common. Many computers are now able to type your speech for you, even in different languages.

If you have an iPhone using iOS6 or later, for example, you can turn on speech recognition. See a demonstration below:

Try For Yourself

You can enable dictation and speak to your computer!

To activate dictation in Windows 7 or higher:

  1. Click the start button;
  2. Go to "All programs";
  3. Open "Accessories";
  4. Open "Ease of Access";
  5. Open "Windows Speech Recognition";
  6. Windows will take you through a 9-step process to set up dictation;
  7. You may then take an extensive tutorial on how to use dictation;
  8. The Speech Recognition Status Window (a very small panel with a microphone button at left) will be visible;
  9. Click the microphone button when you want to dictate; you can also control your computer with speech commands.

It should be noted that Windows speech recognition works not only for dictation, but also for controlling your Windows computer with voice commands. However, background noise can be a problem; when I tried to control my computer while my spouse was doing the dishes, the computer became too confused.

On a Mac, You can also do (1) dictation and (2) voice commands. Unlike Windows, the two are separate features. To enable voice commands, go to the System Preferences, Accessibility, and "Speakable Items."

To activate dictation in Mac OS X v. 10.8 (Mountain Lion) or higher:

  1. Go to the System Preferences;
  2. Open "Dictation and Speech";
  3. Click on "Dictation" at the top;
  4. Turn dictation on;
  5. If you want, you can choose (a) your shortcut key to activate dictations, and/or (b) which language you want to dictate in (there are 19 dialects of 8 languages).

The default shortcut key is to press the "Fn" (Function) key twice, though you can change that to whatever you want. Just make sure you are in a place where typing is possible.

Dictation on the two platforms have good points and bad points. On Windows, you can do dictation without an Internet connection, and you can speak for as long as you like. On a Mac, you need an Internet connection, and your dictation is limited to 30-second snippets. In these respects, Window's system is clearly better.

However, Apple's dictation tends to be more accurate, with fewer errors and suggestions for corrections where the speech was unclear.

You can also activate Dictation on an iOS device (iPhone, iPod, or iPad) running iOS 6 or later. If Siri is activated, then you dictation is already activated. You can tell by going to any place where a keyboard appears; after a few seconds, a microphone button should appear at the bottom of the keyboard. If you see none, then you can activate it.

To activate Dictation in iOS6 or higher:

  1. Go to the "Settings" app;
  2. Open "General";
  3. Tap on "Siri";
  4. Turn Siri on.

Go to an app which allows you to type. After a few seconds, you will see a microphone button next to the space bar. Press that, speak your message, then tap the button to stop.


Another means of visual input is a scanner. Essentially, a scanner is like the top of a copy machine. It is able to photograph a document laying on the scanner's glass bed. The document can be scanned at various magnifications, usually measured in "dpi," or "dots per inch." Dots per inch, when used with printers, does not mean "pixels per inch"—but here it does. If you scan a 1-inch square image at 300dpi, it will be 300 by 300 pixels.

All-in-one printers (which can print, copy, and fax) can also scan as well. Some office-style copy machines can also act as scanners. There are other kinds of scanners, also. Handheld wand scanners can scan anything you can skim the wand over, such as pages of a book. Barcode scanners can scan for information in barcodes or 3-D QR codes (many smartphones can do this also). Film scanners can transfer images on film negatives to a computer.

Other Input Devices

Motion Sensors

A newer technology beginning to become popular is motion sensing. This allows camera to see your eyes, face, hands, and body. The technology "sees" what you do and can react to that. Some video games have such a system, where if you move your body, your screen character moves in the same way.

Currently, a company called "Leap Motion" sells a device about the size of a smartphone for $80. You place the device in front of the computer, and it allows programs with the right features the ability to react to your hand gestures. See a video for the technology below.

This technology will grow over time, and will include more and more features. The new OS for Apple's iPhone, iOS7, includes eye-tracking software in order to create 3-D effects. Expect your computer and other devices to become much more flexible in accepting input.

Already, however, there are some controls that may be built into you phone! As shown in this video, if you use an iPhone with iOS7, go to the Preferences app, go to General and then Accessibility, and then to Switch Control. By choosing a "Camera" source, you can choose moving your head to the left or to the right as a control. You can use a head movement to activate various apps or functions.

Terms to Know

extended keyboarda large keyboard with navigation keys and a numeric keypad added on the right side of a standard keyboard layout.
ergonomica design intended to fit the human form.
keyboard layouta specific assignment of characters to a keyboard.
JISthe standard Japanese keyboard layout.
dvoraka keyboard layout optimized for touch typing.
control devicea device that allows you to control a computer, especially the cursor, such as a mouse, trackpad, or trackball.
cursorthe pointer on your screen.
trackballa control device that allows you to control the cursor using a freely moving ball.
trackpada touch-sensitive surface which allows you to control the cursor.
gesturea motion performed with one or more fingers which activate a special action; for example, two fingers swiping up and down performs the scrolling action.
swipedragging a finger across a touch-sensitive surface.
multitoucha touch-sensitive surface able to sense the movement of more than one finger.
touchscreena touch-sensitive video monitor.
webcama camera for a computer, mostly used for video conferencing.
Speech recognitionthe ability of a computer to understand and/or transcribe speech.
motion sensorthe ability to detect a user's physical presence and create effects on a computer related to the user's movement.

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