Common Input Devices

In this video from ITFreeTraining, I will look at common input devices that are used by a computer. These devices allow the computer to take input from the user. This is the fundamental way that we are able to control what a computer does.

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Input Devices
0:13 To start with, let’s have a look at what input devices are available. These devices take many different forms, but generally fit the categories of keyboard, mouse or controllers. These devices are also called Human Interface Devices or HID.

Human interface devices provide the computer with input to allow the computer to operate. That is, they allow the user to interact with the computer, in order to get the computer to do something. There are also other devices, like security and credentials devices, which fit the category of human input devices. However, I will have a look at those in a different video. To start with, I will have a look at the keyboard.

Keyboards
0:54 The keyboard is the oldest, but remains the primary way to provide input to your computer. Back in the 1980s, IBM introduced a keyboard called the Model M keyboard. This keyboard was quite popular and many of us who used the IBM back in those days will remember it. One reason is that it was very distinctive in design and shape. The design was made of very tough plastic and inside there were metal components, thus making it very strong and heavy for a keyboard. But, one of the big reasons that people remember it was for the sound that it made. Pressing the keys on the keyboard made a very distinctive sound as you can hear.

The reason for this is that each key on the keyboard is essentially a switch. Each switch has its own spring. You can see here the spring under the key. This is what gives each key that distinctive sound. Given the material the keyboard is made of and that each key has its own spring, these keyboards were expensive to make. So, as time passed, these keyboards started to disappear and were replaced by keyboards that were cheaper to make.

Let’s have a look at how keyboards have changed to make them cheaper and easier to make.

Membrane Keyboard
2:05 The first keyboard I will look at is the membrane keyboard. This keyboard is essentially a pressure pad that, when pressed, makes a circuit. Membrane keyboards are often used in devices like electronic devices, for example the control panel on devices like a Microwave oven.

To get a better understanding of these keyboards, consider this flexible keyboard. Essentially this is a membrane keyboard with a flexible cover. If you have ever used a keyboard like this, you will know they are not the best for doing a lot of typing on. This is because the keys are difficult to press. Sometimes you may press a key and it does not make contact. The key also does not spring back into place.

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References
“The Official CompTIA A+ Core Study Guide (Exam 220-1001)” Chapter 3 Position 12401-13237
“CompTIA A+ Certification exam guide. Tenth edition” Pages 402 – 405, 410 – 412
“File:IBM Model M.png” https://en.wikipedia.org/wiki/File:IB...
“File:Typing - Model M 1986.ogg” https://en.wikipedia.org/wiki/File:Ty...
“File:Unicomp space saver model m. with removed key 3864555240 9a2c6b95da o.jpg” https://en.wikipedia.org/wiki/File:Un...
“Keyboard technology” https://en.wikipedia.org/wiki/Keyboar...
“File:Membrane keyboard diagram FULL SCALE.png” https://en.wikipedia.org/wiki/File:Me...
“Cherry switch animation” https://www.cherrymx.de/en/mx-origina...
“File:Trackball-Kensington-ExpertMouse5.jpg” https://commons.wikimedia.org/wiki/Fi...
“File:Acer CB5-311 series touchpad.jpg” https://en.wikipedia.org/wiki/File:Ac...
“File:Mouse mechanism diagram.svg” https://en.wikipedia.org/wiki/File:Mo...
“File:Logitechms48.jpg” https://en.wikipedia.org/wiki/File:Lo...
“File:Mouse-Systems-Mousepad-Detail.jpg” https://commons.wikimedia.org/wiki/Fi...
“Computer mouse” https://en.wikipedia.org/wiki/Compute...
“Sound: Model M keyboard sound” https://en.wikipedia.org/wiki/File:Ty...

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