Raspberry Pi – A first slice

Submitted by peter on Sun, 01/01/2023 - 12:29

Raspberry Pi, a delicious sweet slice of computing power you can use for anything. Here is where you start.

Who wants Pi?

Raspberry Pi computers are the best blend for people who want to experiment and learn. Low cost so anyone with a hobby can add a slice of Pi. The best documentation for beginners. The widest range of add-on components for any project. From raw beginner to professional, the Pi is the best choice for developing projects.

Experienced professionals, after learning and developing on a Pi, will most likely choose an alternative for processing large volumes of data or very high speed processing. A photographer moving from small videos to long 4K videos will want something with a bigger faster GPU. An online shop will want a big database on NVMe storage, something not practical on a Pi. None of those requirements will stop initial low volume development and learning on a Pi.

What do you want first?

There are multiple choices with in the Raspberry Pi range. If someone gives you a Pi, start experimenting and learning with that slice. For those buying their first slice, here are my recommendations. Prices are in Australian dollars at Core Electronics, https://core-electronics.com.au, on the day I am writing this.

The smaller model Pi computers have limitations you will hit in some experiments. The smaller models have limitations making the initial learning stage more difficult. Start with the top model, the Raspberry Pi model 4. You can do anything with the model 4 then transfer the project to other smaller cheaper models when the project no longer requires the full power of the Pi 4 for development.

The Pi 4 is available with 2 GB or 4 GB or 8 GB of memory. I worked on heaps of development projects using a 4 GB notebook. In Linux, the memory usage rarely ran over 2 GB. For working on one project at a time, 2 GB is all you need. The 4 GB version is just $13 more but is out of stock. I would be happy with either.

You need a power supply. Start with an official power supply. If you find something cheaper later on, you will have the official power supply for comparisons. The official supply actually supplies 5.1 volts instead of 5 volts, which helps the Pi computer deliver a full 5 volts in the on board USB sockets. The only time I use alternatives is when running smaller models on battery or solar.

You need the Raspberry Pi Operating System and that is a free download I will mention later.

You need a microSD card for the operating system. Start with something good and reliable. Amazon AU has some good choices at reasonable prices and some of the best choices are often on sale. I recommend, for your first card, the Sandisk Extreme microSD card with a minimum write speed of V30 and the A1 rating for system use. Both speed ratings will make your work faster. V60 is only need for 4K video. A2 is better but too expensive compared to the small benefit. There are other brands with cards as good as Sandisk but the Sandisk brand is more likely to be on sale at a good price.

Any USB keyboard can be used for input. Our local Kmart shops sell a full size keyboard for $7.50. For frequent typing, try several and choose the most comfortable. I have a $10 Kmart keyboard I dislike and use only for experiments on a spare computer. I like a $110 keyboard and use it for frequent typing.

Any USB mouse. The cheaper ones are popular with most people. I find them a bit small for my hands. If you are happy with the Kmart keyboard, grab the Kmart mouse.

You need a good HDMI cable to connect to a monitor or TV. The official specifications describe the two HDMI sockets on a model 4 Pi as "micro-HDMI ports (up to 4kp60 supported)". Unofficial sources say it is HDMI 2.0. Start with the official HDMI cable to ensure you have the maximum capability with any monitor. Alternatives include a micro-HDMI to HDMI adaptor but the resultant combination might not give you the full capability. Start with the official HDMI cable for the Pi 4.

There are many cooling options for the Raspberry Pi computers. Summers in my location are hot. The Pi 3B never needed cooling. Two of the Pi 4 chips run hot when working hard so I added 3 heatsinks. Avoid noisy fans.

There are a heap of cases for the Pi 4 and I did not add any of the promoted cases as they limit cooling or use a noise fan or contain metal which limits WiFi range. I like the clear plastic bone shape cases as you can place them in any position and still have good air flow. Search for Raspberry Pi 4 case dog bone. Aliexpress.com was the cheapest source for anyone happy to wait. You can also get a nice base plate to mount a Raspberry Pi on one side and a development board on the other side, something you could use when you move from experimenting with software to experimenting with electronics. I bought both. They also work with my Pi 3B.

Device

Price AU$

Raspberry Pi 4 Model B 2GB

79.66

Raspberry Pi 4 Power Supply (Official) - USB-C 5.1V 15.3W (Black)

14.35

Raspberry Pi OS download

0.00

microSD card 32 GB Sandisk Extreme microSDHC V30 A1

15.95

USB keyboard

7.50

USB mouse

4.25

Micro-HDMI to Standard HDMI 1M Cable

7.65

3pc Heatsink Kit for Raspberry Pi 4

2.20

Total

131.56


 

You can add any monitor or TV with HDMI input. With two cables, you can use both HDMI sockets on the model 4 to form one big screen from two smaller ones or use one screen for development and the other screen to show your tests.

The operating system you first use would be the modern 64 bit desktop version from https://www.raspberrypi.com/software/operating-systems/, listed as Raspberry Pi OS (64-bit). The same version can be used on the Pi model 3B and the new Zero 2 W. If you are using older models of Pi, you need the 32 bit version listed as Raspberry Pi OS. They look and work the same. I currently use the 32 bit version as I have the old model Zero W and the new Zero 2 W is out of stock.

There is a Lite version of the OS with no GUI, Graphical User Interface. After you learn how to use the Raspberry Pi with the desktop version, you might experiment with the Lite version for some projects. You can develop most projects on the desktop version then transfer the work to the Lite version. The Pi 4, 3B, and Zero 2 W have the power to run the desktop version instead of switching to the Lite version. All you do is alter the startup to start without the GUI. The GUI can then be started with remote access for monitoring and reconfiguring a project.

Documentation is useful. I found the documentation offered in kits is almost useless. Everything is online for a free download. You are better off choosing your first project then look for articles on that type of project, starting from the simple versions then moving up as you learn.

When do you reach for a Pi?

Some experience with Linux can help. You might convert an old computer to Linux for experiments. I recommend Linux Mint, https://linuxmint.com/, as a beginner's replacement for Windows or MacOS on an Intel or AMD based computer. There is a Raspberry Pi Desktop operating system for Intel machines but the support forums are not as good as the forums for Linux Mint, https://forums.linuxmint.com/. When you are happy using Linux, buy a Pi.

The Raspberry Pi foundation supports users as young as eight through their code clubs. If you have anyone nearby with some experience of Linux, you can dive straight in to a Pi. My experience of helping people is getting them through the first couple of weeks when they are up against learning different terminology. Their online searches for help often fail because they do not know the right words to use in a search. After those initial hints, they are free to learn at their own speed without help.

Conventional computers are hard to connect into electronics projects. Arduino computers were popular but difficult to learn outside of a dedicated classroom. The Raspberry Pi works the same as a conventional computer and connects to electronics almost the same as an Arduino.

After your first Pi 4, you might look at a cheaper model for some projects. Here are the options I use or will use.

The Pi 3B is cheaper but misses out on USB 3. The built in Ethernet speed is limited as it runs through the internal USB 2 chip. I might use my old 3B for a low volume media server or sell it and buy another Pi 4 to get full Gigabit Ethernet speed.

The Pi Zero 2 W is the next step down for many projects and will be my next purchase when they are readily available. You get good WiFi but only USB 2 and no wired Ethernet. If you need a wired connection, the USB 2 speed will be a limitation. I have projects lined up using WiFi and the use of a Zero 2 W depends purely on the WiFi range.

The Pi Zero W is slightly cheaper and is in stock and is good for my smaller projects. The WiFi range is ok for use inside a house. For my next project, I have to test through walls to access a Wifi router inside my house from outside.

I have a Pi Zero with no WiFi and might use it if the Zero W WiFi range is not enough. I can add a more powerful WiFi adaptor through the Pi Zero USB.

Pico is the Pi below Zero. The Pico is not a conventional computer board. The Pico requires special loading of software. Develop on something else then load onto the Pico. Given the low cost of the Zero, I would not use a Pico for any of my projects.

Where can you use a Pi?

The Raspberry Pi is sold or supported in 160 countries. The only limitation I can think of is the need for heatsinks on the Pi 4 in hot weather. The power usage is so low that battery usage is viable and the screen will use more power, making the Pi one of the less energy expensive parts of a project. If you enclose a Pi, the enclosure might need a fan.

For pure software projects, a second hand notebook is the main competition. I have an old notebook with USB 3. The equivalent would be a Pi 4 plus screen, keyboard, and battery backup. The all up cost of the Pi equivalent is less than what the notebook cost new but double what the notebook is worth second hand. The notebook has an excellent case and a built in SSD. The notebook beats a Pi when you want to slip a full working machine in a backpack.

For huge volumes of data, a desktop case can take multiple disks of any type and capacity. I have one on the network for backing up everything else.

The Pi wins when you want direct digital low voltage electronic connections. Anything else would need a network connection to something like a Pi Zero to translate the electronics.

The Pi computers are small and light enough to use in robots. The Pi Zero 2 W has the processing speed for amazing intelligence and WiFi good enough for use in the same room. I do not have a Zero 2 W to test for maximum range.

The Pi 4 can replace the low end of both desk bound notebook computers and desktop computers. The Pi 4 lacks only NVMe for very fast storage and a giant GPU for high intensity games.

The lack of a fan means you can use the Pi range in absolutely the quietest environments. Use SSD instead of rotating disks. Use an open case and heatsinks for cooling. Perfect for a server of any variety in the same room as a human. The human, the keyboard, the espresso machine, and the birds in the tree near the window will be the only sources of noise.

Why choose a Pi now?

The top end and the bottom end of the Pi range were limited, forcing many people to use other computers for development and things like Arduino chips at the bottom end. Now the Pi range extends far enough at both ends to allow the full process to remain on slices of Pi.

The Pi Zero replaced Arduino for many uses and the Pico replaces the last uses of Arduino. There are also other smaller and cheaper options.

The Pi 4 has USB 3, replacing one popular requirement for alternative computers, things like the Intel NUC series, and the Pi 4 range extends up above the 1 GB of RAM limitation for development systems. When you do not need the portability of a notebook during the development phase, a Pi 4 works. The low cost of a Pi 4 lets you set up a dedicated development along side of your notebook.

2023 should see Pi production increase to the point where all the models are available all the time.

Way to go?

I started using Linux for servers. I had Windows notebook and converted an old Windows desktop converted to Linux. The notebook was eventually upgraded to dual boot with Linux along side of Windows. Then pure Linux on the notebook. I looked at projects with Raspberry Pi computers connected to Arduino devices but decided to not learn two different systems.

The expansion of the Pi range removed the Arduino roadblock. I renovated a house and looked at irrigation systems. The systems had so many limitations. Some Pi magic could irrigate with no limitations. The same Pi magic could solve many other problems.

Linux Mint made the Windows to Linux conversion easy and the helpful people in the Linux Mint forums helped. There are other Linux related forums where the people are more likely to argue instead of help.

The Pi 3B and the helpful people in the Raspberry Pi forum guided me into some experiments. The 3B was a bit slow for some development work and the Pi 4 solved that problem. The only remaining experiment is to find the maximum range of the Pi Zero W WiFi.

After you experiment with the software, visit Core Electronics or equivalent and work through some of the examples. Start with a breadboard, some jumper leads, resistors, and LEDs. Visit https://core-electronics.com.au/guides/raspberry-pi/ then choose something like https://core-electronics.com.au/guides/raspberry-pi/how-to-use-gpio-raspberry-pi/ to experiment with a breadboard and the Pi GPIO pins. In Australia, you can order everything direct from the same site.

My irrigation project will use a Pi to control some relays, https://core-electronics.com.au/5v-4-channel-relay-module-10a.html, which will switch on some valves, https://core-electronics.com.au/12v-solenoid-valve-3-4.html, and the rest is just plastic irrigation parts and pipes from the local hardware shop.

Learn to use Linux then Python then GPIO.

Worth the work?

I converted from Windows to Linux because Microsoft was making Windows more difficult and less reliable while Linux Mint made everything easier and more reliable. Based on my experience with Linux, I experimented with the Raspberry Pi model 3B.

The Pi 4 and Pi Zero range removed what I found as limitations of the 3B. The range of parts at Core Electronics made it easy to assemble some experiments for learning and the projects I am interested in. Everything you need for everyday projects is described in detail online and the parts are easy to acquire. After the initial purchase of the Pi 4 setup, everything else is a really cheap hobby. You spend less than the cost of going to a movie each week.

My entertaining and educational irrigation project logic and controlling valves, less than $200, will beat stupid limited systems costing over $1,000. My version project is also more fun.