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Course: Computers and the Internet > Unit 2
Lesson 4: Computer componentsInput & output devices
As computer users, we're the most familiar with the parts of the computer that we interact with daily: the input and output devices.
Input
The very first computers only accepted "punch cards" as input. Computer scientists had to carefully punch out their instructions and then feed the cards into the computer.
Fortunately, computers have come a long way since the 1970s, and we can now input data into them using a variety of easy-to-use devices. The most common input devices are the keyboard, mouse, and touch screen.
There are hundreds of other input devices, like microphones to capture sound waves, scanners to capture image data, and virtual reality devices to capture our body movements.
Computers also receive input from their environment using "sensors", like motion sensors that detect changes in movement.
🤔What other input devices have you used? What new input devices will we have 20 years from now?
Output
Once the CPU is done processing the data, it often needs to output a result.
A standard output device is the computer monitor, which displays text, images, and user interface elements by lighting up thousands of pixels with different colors.
There are many other ways a computer could output data. As long as the output device can interpret a stream of 1s and 0s, it can turn that data into anything - headphones output sound, printers output ink on paper, and projectors output light.
Exploring inputs and outputs
Discover more types of inputs and outputs in the upcoming exercises.
🔍 If you've never heard of a device before, just search for more information online.
🤔 Can you think of other output devices? What's a new output device that you could invent?
🙋🏽🙋🏻♀️🙋🏿♂️Do you have any questions about this topic? We'd love to answer— just ask in the questions area below!
Want to join the conversation?
- How exactly does the computer know which ones and zeros stand for different things? For example, if you type the letter B, how does it distinguish it from a different type of input?(14 votes)
- Great question. When you press a key, your keyboard sends a particular "scancode" to the computer. The scancode represents the key that was pressed.
Here's an example of scancodes sent by IBM keyboards: https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/com.ibm.aix.keyboardtechref/doc/kybdtech/Key.htm
The scan code is then interpreted by programs running on the computer (like the keyboard "driver"), and the pressed key information becomes available to the other programs running.
If a program wants the computer to store the pressed key in memory, it will often store characters using the "ASCII" encoding standard. You can see the codes for that here:
https://www.ascii-code.com/
Uppercase "B" is 01000010, so that's what the computer would store in memory.(28 votes)
- At my house, I have a small color sensor for a lego toy. When I turn it on, it emits a beam of light and reads what the color is that it’s above. I’m trying to figure out if it’s an input or output device.
1. It has an on switch - input
2. It emits a light beam - output
3. It reads colors - input
4. It tells what color it’s reading - output
It looks to me as if it’s a combination of the two. Are instruments such as this better categorized as their own computer as they have input and output?(4 votes)- This is a really great question! You're right that it has both input and output qualities. Although when determining if something is mainly an input or output device, it's best to think of it in relation to a computer. If the device's main purpose is to gather information for the computer, then it's an input device. If its main purpose is to let the computer communicate information to the user, then it's an output device.
Although the color sensor has some input qualities and some output qualities, I would say its main function is to read colors. The other features are there just to help it with its main function (reading colors). So I would say that it's an input device. You could also count it as its own computer, with its own inputs and outputs, but typically that's not how it's categorized.
Hope this made sense! (:(8 votes)
- What is an Arduino computer which is mentioned in above exercise?(4 votes)
- An Arduino computer is a very small computer. Think of it as a small motherboard. There are many things that can be added onto an Arduino which can allow it to do many different things.(5 votes)
- Do analog devices or noncomputerized appliances also count as input and output? For example, does my Polaroid camera function as both an input and output device? Are the faucets at my sink considered input while the taps are considered output?(5 votes)
- Short answer, at least, from what I can tell, yes...? If you think about it in that way, yes, they do count, but if you count only electronic devices, then no.
It depends on what you think counts.(1 vote)
- also are these other questions fake or something everyone here sounds like npcs(4 votes)
- I think the 3 d printer should be input and output, this right?(2 votes)
- You could say that, but I would rather think of it as an output device. The thing is if it's also an input device, what's it outputting to 🤔? I wouldn't think of a printed plastic model as another computer, which makes it hard to think of the plastic as another thing capable of "inputting" a stream of 1's and 0's that tell a printer to print stuff.(3 votes)
- Is a radar input or output or both?(2 votes)
- A radar is a system that contains both input and output portions. When the radar receives the signal that it is being turned on, it begins to take in information through the measuring of the radio waves it sends out. This is the output portion. When it sends the information back to wherever it is told to go, it is now an output.(2 votes)
- How does the computer know what its doing and does it make any mistakes.(2 votes)
- It's a machine. Engineers want computers to act mechanically, so they use a lot of math and logic when organizing a computer system! this in turn gives the computer a lot of structure, which also serves to clarify its functionality! You have to admit that it's hard to make mistakes, when you're thinking is clear, and your work is neat!(1 vote)
- all these smart people making me feel dumb(2 votes)
- is a faxing machine an input or output devise(2 votes)
- Depends on how you plugged it in.
Is your faxing machine hooked up to your computer? Then we say its an input device for your computer!
Did you decide to fax some of your word documents? Then we say your faxing machine is an output device for your computer, which outputs your word documents to the world!"
is your computer hooked up to your fax machine, which is also hooked up to a projector? Then we can say that its both an input and an output device!
TLDR: depends on how you're using it along with other computing systems 😃.(0 votes)