Build a  Raspberry Pi 4 B Powered Desktop Computer
Part Two:  The Parts.  What are these things for?
Liz Berry

In Part One of this Non-Geek DIY you learned about all the parts you need to build a Raspberry Pi 4B Powered Desktop Computer and their approximate cost.  I recommended the purchase of a CanaKit from the Internet as the easiest and most economical way to secure all the parts you need for this build.  You can obtain everything you need in one package for $97 plus tax except for the HDMI monitor, the USB keyboard and mouse. Of course, you can purchase them separately, but my research showed this to be the more expensive and possibly frustrating path as one electronics store is not likely to have all the parts you need

In Part Two you will learn about the function of all these parts.  Learning about the parts, the materials used to build a thing is the foundation for learning how it works.  And thus, we will begin with information about the MicroSD card which will function as the hard drive for your Raspberry Pi 4B Powered Desktop Computer.


PART #1.  MicroSD card (pre-loaded with Noobs) 32GB. Estimated cost:  $18.98

The microSD card arrives in a protective envelope.  (Noobs stands for “New Out of the Box Software.”)  A MicroSD card preloaded with Noobs makes the installation process so much simpler. The SD card is a key part of the Raspberry Pi. It provides the initial storage for the Operating System and files. Storage later can be extended through many types of USB connected peripherals.  Think of it this way:  The Raspberry Pi is merely a circuit board with a CPU and the SD card is its hard drive.  This little microSD card is already loaded with a Raspbian/Debian Linux based operating system and lots of great software that comes with this open-source operating system.  For example, you’ll get the latest version of the Linux answer to the Microsoft Office Suite:  LibreOffice Writer; LibreOffice Math; LibreOffice Impress; LibreOffice Draw; LibreOffice Calc; and LibreOffice Base.  You’ll also get the Integrated Development Environment for Python so you can learn how to code in Python (the language spoken by Raspberry PI) as well as some other games and accessories.  Of course, since this is a Linux system, you’ll have access to powerful Linux Command Line.  I’ll get into that later.

For those not familiar with Linux, it has many different distributions.  Debian is one of its distributions.  Ubuntu and Fedora are two other types of distributions.  A Linux distribution is an operating system made from a software collection, which is based upon the Linux kernel.  The Linux software collection that comes with Debian includes an Integrated Development Environment for Python, Minecraft, the LibreOffice Suite (similar to Microsoft Office), various accessories such as a calculator, SD card copies, Terminal, etc. and of course a Chromium Web Browser, Raspberry Pi Resources, Claws Mail, a VNC viewer.  Debian is the recommended Linux distribution from the Raspberry Pi Foundation.  Of course, you can choose from thousands of other open source software to add to the distribution you have on your Debian based  version of Linux.

PART #2.  USB-C Power Adapter Estimated cost: $27.77

This is a power supply for electronic devices.  You plug one end into a wall outlet and the other end into the micro USB power supply port on the Raspberry Pi and it converts AC to a single DC voltage and provides the electricity for your computer. 

Note:  The difference between AC and DC lies in the direction in which the electrons flow. In DC, the electrons flow steadily in a single direction, or “forward.” In AC, electrons keep switching directions, sometimes going “forward” and then going “backward.”

Most electronic components are DC, uni-polar both by design and function; – they need a steady state, non-varying voltage supply for optimum function (perhaps); mostly they are low voltage which can be supplied by both converted AC and / or batteries (therefore making them portable and mobile) and finally – cost and economic reasons.

PART #3. Micro HDMI CABLE  Estimated cost:  $8.95

One end of this cable has a micro insert and the other end is a regular sized HDMI insert.  For some reason they made the Raspberry Pi 4 with a micro HDMI port.  The previous Raspberry Pi’s all had regular sized HDMI port.  The purpose of this cable is to connect your Raspberry Pi (the CPU) to your monitor so it will display information and graphics from your software and the Internet on your monitor.  Thus remember, if you are purchasing your parts separately, don’t let some busy store clerk sell you a standard HDMI cable with both ends the same large input size.  One end of the HDMI cable must look like the same end of the plug you put into your phone to charge it. 

By the way, HDMI stands for(High-Definition Multimedia Interface) which is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television or digital audio device.


PART #4. Raspberry Pi 4B 4 GB-the engine for your computer Estimated cost: $55.00


Eben Christopher Upton

Eben Christopher Upton CBE is a British technical director and ASIC architect for Broadcom. He is also a founder and former trustee of the Raspberry Pi Foundation, and now CEO of Raspberry Pi Ltd., the wholly owned subsidiary which runs the engineering and trading activities of the Foundation.

Raspberry Pi is the name of a series of single-board computers made by the Raspberry Pi Foundation,  a UK charity that aims to educate people in computing and create easier access to computing education.

The Raspberry Pi launched in 2012, and there have been several iterations and variations released since then. The original Pi had a single-core 700MHz CPU and just 256MB RAM.   All over the world, people use the Raspberry Pi to learn programming skills, build hardware projects, do home automation, and even use them in industrial applications.

The Raspberry Pi is a very cheap computer that runs Linux, but it also provides a set of GPIO (general purpose input/output) pins that allow you to control electronic components for physical computing and explore the Internet of Things (IoT).

For lots of information on the Raspberry Pi, be sure to visit their website at  Below is a diagram of the Raspberry Pi 4 and following that, a more detailed description.

This is the tiny, credit card sized circuit board, once all the necessary parts are attached to it, will run your computer with a Debian distribution of a Linux System.  Some folks ask if a Raspberry Pi can run a Windows 10 desktop apps.  The Pi 4 can run Windows desktop apps, although it requires an awful lot of effort to do so, and even then, apps will only run poorly. I don’t recommend it.  Learn Linux instead.

Raspberry Pi 4 B

RAM (Random Access Memory) – one of the most important components of desktop PCs, laptops, tablets, smartphones, and gaming consoles. Without it, doing just about anything on any system would be much, much slower. Even not having enough for the application or game you’re trying to run can bring things to a crawl, or make it so they can’t even run at all.  Generally speaking, the more RAM, the faster your computing device will do what you tell. It to do.

If you are a light user as many people are, you can do with 4 GB of RAM. A majority of people go with 8 GB RAM. However, if you plan to do photo editing or video editing, 8GB RAM will not be enough. You need a minimum of 16 GB.

NOTE:  As a non-geek user of a Raspberry Pi powered with a Raspberry Pi 3B which only has 1GB of Ram, I can tell you that my computer has been plenty fast except for watching videos which are watchable, but tend to break up along the way.  I understand the Raspberry Pi 4 is three times faster and will be sufficient for that.

Gigabit Ethernet port– In computer networking, Gigabit Ethernet include the various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802.3ab standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks, as a result of being considerably faster.  It is currently used as the backbone in many enterprise networks.  One of the advantages of ethernet is that it is faster than WIFI. 

A hard-wired connection allows internet access to pass directly from an access point to a device, via an ethernet cable. WiFi uses a wireless connection to pass data between a router and a device. Hard-wired internet connections offer improved speed and stability, as well as significantly lower EMF radiation.

Also, it is likely that you will have to pay extra to your provider for ethernet connectivity to your router.  Certainly, for Non-Geek users like me, wired Ethernet connectivity is over the top.  I doubt I’ll ever use this port.

USB 2 and 3 PORTS – You’ll see the Raspberry Pi 4 has four USB ports.  You can also expand the number of USB ports by plugging in Hubs. We’ll talk about that in a much later version of Non-Geek DIY.  The difference between USB 2 and USB 3 ports is the rate at which they transfer data.  (USB 2.0 transfer speed is 480 megabits per second (Mbps), while USB 3.0 transfer speed is 4,800 Mbps. This means USB 3.0 is approximately 10 times faster than USB 2.0. More recently, USB 3.1 has also been released and has a data transfer rate of 10,000 Mbps)

Two of the USB ports will be used for your keyboard and mouse.  The USB ports also enable the attachment of peripherals such as webcams that provide the Pi with additional functionality.  Save the USB 3 ports (the blue ones)  for other peripherals and use the USB 2 ports (the black ones) for your mouse and keyboard.

Headphone or speaker jack – In between the USB ports and the HDMI ports, you’ll see a little round input The Raspberry Pi has two audio output modes: HDMI and headphone jack. You can switch between these modes at any time.

Your HDMI monitor or TV most likely has built-in speakers, and thus the audio can be played over the HDMI cable, but you can switch it to a set of headphones or other speakers plugged into the headphone jack.  For now, if you are a non-Geek just ignore this audio jack (port).

Two HDMI ports – The Raspberry Pi 4 comes with two HDMI mini ports.  This enables you to run two monitors at the same time.  If you want to run two monitors from your Raspberry Pi 4, please visit the official Raspberry Pi site as there is a specific way to set up two monitors.  If you are a Non-Geek like me and have no idea why someone would want two monitors, just skip this part.

USB C Power Supply – This is where you will plug in your USB C Power Supply cord.  The other end will be plugged into an electrical outlet or Power Supply strip in your home.

More Powerful Processor -The Raspberry Pi isn’t the world’s fastest super-computer, but it just might be the best supported. They can be used to power everything from Christmas lights, video game consoles, media servers, and home automation hubs, and they do an excellent job. The new version 4B  and its better specs mean the use case has expanded for anything that needed just a little more power, and the bump in graphical abilities means it makes for an even better entertainment device. But that doesn’t mean the model 3B+ suddenly becomes obsolete; if it works for you now, it’s going to keep working for a long time.  I might give my Raspberry Pi 3B powered desktop computer to one of my grandchildren.  It does work great as I’ve mentioned and the Debian Linux version I installed comes with Minecraft and other games and educational software for kids like Scratch.  AND all kids need to learn, not only about Raspberry Pi, but also about the great wild world of Linux.

The GPIO Pins – A powerful feature of the Raspberry Pi is the row of GPIO (general-purpose input/output) pins along the top edge of the board. A 40-pin GPIO header is found on all current Raspberry Pi boards.  You can connect a device to specific GPIO pin and control it with a software program.  We will delve deeper into using GPIO pins in future Raspberry Pi projects.


PART #5. Clear Plastic Case for Raspberry Pi – Estimated cost $7.00

There are many cases out there for the Raspberry PI.  If you are a Maker with a 3D printer, you can even print one.  Most likely Tinker Cad has all kinds of programs available for printing them out.  I prefer a clear plastic case because I like to see it.  Even though you can leave it out in the open and it will still function, a case is recommended.

DO NOT PUT THE MICRO SD CARD into its Raspberry Pi slot until you have put the Raspberry Pi in its case. (Note:  the SD slot is located on the bottom side of the Raspberry Pi and thus not shown in our photo.)  When inserted, a part of the micro SD card will stick out for easy removal.  If you try to put it in beforehand, you will likely damage your SD Card (which is actually your hard drive).

Hold it at the edges.

PART #6.  Five-volt fan $15.95

Most of the information I read on the Raspberry Pi advises that you install a fan in the case.   Make sure to select a case that will accommodate a fan.  Not only does the CPU get appreciably hot even under normal load, there are a number of other parts of the board that are reported to heat up to the point they are uncomfortable to touch.

PART # 7. Heat Sinks – $2.00

For the Raspberry Pi they come in sets of three.

A component designed to lower the temperature of an electronic device by dissipating heat into the surrounding air. … A heat sink without a fan is called a passive heat sink; a heat sink with a fan is called an active heat sink.  Heat sinks are generally made of an aluminum alloy and often have fins.

The placement for the three heat sinks (three white pieces near center of board) is shown in the photo below.  Detail will be provided in PART THREE—Non-Geek Setup of a Raspberry Pi 4 computer.

Placement of the Three Heat Sinks

PART #8. On/Off USB pi Switch – Estimated Cost $5.00

If you are currently classified as a non-geek, you likely won’t have much use for this part for quite a while—if ever.  It can be set up to shut on/off your USB power consumption.  Mostly useful for Raspberry Pi projects running on battery power.  However, this part came with my Canna Kit and I’ll be hanging onto it for perhaps future use.  It’s just not necessary now for initially setting up my Raspberry Pi 4 desktop computer.

PART # 9. Micro SD Card Reader – Estimated Cost $6.99

This part also came in my Canna Kit of parts.  I hope I won’t have to use it. You stick the Micro SD card into this reader and then plug the reader into a USB port on your regular computer. You would then go to the Raspberry Pi org site and download the latest Noobs, Debian Linux distribution for loading this Micro SD card.  Once loaded and after you put the Raspberry Pi in its case, you will insert the Micro SD card.  This card is in essence the hard drive for your Raspberry Pi desktop computer.

Since the Micro SD card from Canna Kit is pre-loaded, he only time you would need to use this reader is 1) if you find that the Micro SD card is damaged or 2) late you want to update your version of Debian.


Coming Soon!
Build a  Raspberry Pi 4 B Powered Desktop Computer
Part Three:  The Build

Part One was an introduction to this build.  We explored why anyone should even attempt to build a Raspberry Pi desktop computer; some of its uses;  required parts and their estimated cost. Part Two has been an education regarding each of the parts and their functions.  Part Three will be the steps of the build—culminating with running a desktop computer powered by a Raspberry Pi 4 circuit board with a loaded Noobs Micro SD card for a hard drive.


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