What is raspberry pie

What is Raspberry Pi? Specs and Models (2021 Guide)


Are you curious about the IoT (Internet of Things?) Have you always wanted to try to make your own robot, smart mirror, or bird feeder camera? What about building a computer for a fraction of the cost of a commercially available machine?

If you said yes to any of these questions, you might enjoy playing around with a Raspberry Pi.

In this article, I’ll explain what a Raspberry Pi is (and what it’s not.) Then I’ll show you some things you can use it for, and finally, I’ll list all of the current models along with their specs.

What is Raspberry Pi?

A Raspberry Pi is a single board computer (SBC) created in the United Kingdom by the Raspberry Pi Foundation. It’s a charity that «works to put the power of computing and digital making into the hands of people all over the world.»

The first model of the Raspberry Pi was released in 2012, and as of 2021 there have been five generations of the boards. A microcontroller (more about that later), called the Pico was released in early 2021.


Something that sets the Pi apart from your average computer is the set of 40 GPIO (General Purpose Input Output) pins.

GPIO pins are pretty much exactly what they sound like. They are designed to input and output single bits. This means that you can use them to add all sorts of functionality to your Raspberry Pi using switches, buzzers, lights, sensors, and so on.

Raspberry Pi HATs

There are a number of add-on boards that you can attach to the Raspberry Pi using the GPIO pins.

Raspberry Pi HATs (Hardware Attached on Top) are add-on boards designed according to certain specifications. The Raspberry Pi can automatically detect and configure the HATs, making set-up easy.

There is a huge variety of HATs and other add-on boards that you can buy, but here are some notable ones:

  • PoE+ HAT – Power over Ethernet HAT
  • Sense HAT – Designed for the Astro Pi mission, the Sense HAT includes a gyroscope, an accelerometer, a magnetometer, and sensors for temperature, humidity, and Barometric pressure.
  • Pimoroni Explorer HAT Pro – All-purpose board featuring touch pads, crocodile clip pads, and analog inputs
  • Adafruit Capacitive Touch HAT – Similar to a Makey Makey, this HAT allows you to use any conductive object to trigger events using Python.

Raspberry Pi Operating Systems

The Raspberry Pi often runs some form of Linux, but there are a ton of operating systems that you can use.

On the official website, you will find a list of operating system images available for download. These include the official Raspberry Pi OS, Debian Buster, and Ubuntu (desktop, core, and server.)

You will also find RetroPie, a specialized gaming platform operating system, and LibreELEC, a lightweight Linux distribution specifically created for use with the open source media player Kodi.

Raspberry Pi VS Arduino

You may have heard of Arduino boards and wondered what the difference is between them and the Raspberry Pi.

The main difference is that Pis (with the exception of the Pico and the RP2040) are full computers with operating systems. You can connect your Pi to a keyboard, mouse, and monitor and use it like you would use a Mac or PC.

The Arduino, on the other hand, is a microcontroller. It cannot function independently as a computer, but is programmed using a computer and then used to control things like cameras, lights, robots, and so on.

As the official Arduino website puts it: “Arduino boards are able to read inputs… and turn it into an output.”

What is the Raspberry Pi Used For?

Search the internet and you will find a huge array of projects created using Raspberry Pis.

Common use cases include home automation, gaming consoles, servers, WiFi extenders, streaming devices, weather stations, and home computers. (Fun fact: much of this article was written on a Raspberry Pi.)

During the Covid-19 pandemic, Raspberry Pi’s were even used to control ventilators in some hard-hit areas.

Raspberry Pi Models

All models of Raspberry Pi that are currently in production have 40 GPIO pins.

This list does not include the Raspberry Pi microcontrollers, the Pico and the RP2040.

You can find out where to purchase any of these boards on the Raspberry Pi website.

Model Processor RAM Connectivity USB HDMI Power Price
Zero BCM2835 512MB None Micro USB OTG Mini HDMI Micro USB $5
Zero W BCM2835 512MB 802.11 b/g/n wireless LAN Micro USB OTG Mini HDMI Micro USB $10
Raspberry Pi 1 Model A+ BCM2835 512MB None 1x USB 2.0 Full-size HDMI Micro USB $25
Raspberry Pi 1 Model B+ BCM2835 512MB 100 base ethernet 4x USB 2.0 Full-size HDMI Micro USB $30
Raspberry Pi 3 Model A+ BCM2837B0 512MB dual-band wireless, Bluetooth 4.2 1x USB 2.0 Full-size HDMI 5V DC via Micro USB $25
Raspberry Pi 3 Model B BCM2837 1GB ethernet, wireless, BLE 4x USB 2.0 Full-size HDMI 2.1A via Micro USB $35
Raspberry Pi 3 Model B+ BCM2837B0 1GB dual-band wireless, Bluetooth 4.2, BLE 4x USB 2.0 Full-size HDMI 5V DC via Micro USB & Power-over-Ethernet (PoE) $35
Raspberry Pi 4 Model B BCM2711 2GB, 4GB, or 8GB Gigabit ethernet, dual-band wireless, Bluetooth 2x USB 3.0 & 2x USB 2.0 2x micro HDMI 5V DC via USB-C $35, $55, $75
Raspberry Pi 400 BCM2711 4GB Gigabit ethernet, dual-band wireless, Bluetooth 2x USB 3.0 & 1x USB 2.0 2x micro HDMI 5V DC via USB $70


The Raspberry Pi is an affordable way to explore electronics, hardware, and computer programming. It can be used for a huge variety of projects, from the very silly (like a hamster powered hamster drawing machine) to the very important (like computer labs in developing nations.)

Now that you know the basics, why don’t you go out and make something? Whether you hook a Capacitive Touch HAT up to your Raspberry Pi and turn it into a banana piano or install Linux on it and use it to do your homework, I hope you have a great time creating something cool and useful.


What is Raspberry Pi?

Raspberry Pi is a single-board computer developed in the United Kingdom. Introduced in 2012, Raspberry Pi quickly exceeded its popularity and original mission – to promote and teach basic computer science. Today, virtually every industry has developed a use for Raspberry Pi. Private and public sectors use the economically friendly device for automation, research, and medical applications. Even NASA, the International Space Station, and the UK Space Agency use Raspberry Pi to run applications and collect data.

Learning something new, especially something perceived as highly technical and advanced can be overwhelming. Often, the first steps are the hardest – where do I begin? What do I need? How can I make this happen? Do I have the support I need to find the answers to my questions? Raspberry Pi has everything you need to take your first foray, or advancement, into computer science. First, let’s figure out where you fit, and then we’ll discuss the next steps for that category.

Computer Curious (Newbie)

You are comfortable with your smartphone, can program your DVR and television, and even know how to use smart appliances like a dishwasher or refrigerator. Even if you have kept the technological advancements away from your kitchen, you know how to run the programs on your computer or play video games. You can use technology effectively but find yourself wondering how something runs and why it runs that way. If Python, Scratch, Linux, and Unity are just words to you, then you are computer curious (aka – Newbie). Additionally, if you are working with someone (child, spouse, coworker, etc.) who falls in this category, you, as a group, are a Newbie.

Computer Comfortable

Somewhere between the Newbie and the Old Hand are those who have computer skills above surfing the Internet, email, and basic word processing programs. A Computer Comfortable person entails experience with operating systems, office suites (Microsoft Office and G Suite, for example), presentation software, collaboration tools (Skype, Zoom, Hangouts, etc.), spreadsheets, and accounting software. Through this kind of experience, you have learned basic formulas and programming, and you effectively use these more advanced tools. If you are working with someone who falls into this category, you, as a group, are Computer Comfortable.

Old Hand

You are an Old Hand if you’ve ventured out from established software and hardware. If you’ve built a motherboard, know a little bit of programming code, and can develop a running program, you and whomever you may be working with are in the Old Hand group. You have the skills and experience on which you can develop knowledge that is more intricate and advanced.

Choosing your Pi

Once you have determined your knowledge level, it is time to select the Raspberry Pi board that is best suited to your goals. There are nine models of the Raspberry Pi, ranging in cost from $5.00 to $55.00. The amount of money you want to invest, the time you have to explore and learn, and your ultimate goals determine which model you buy. Each model is compatible with one another. If you start with the Raspberry Pi Zero, the lowest-cost single-board computer, and decide you need a Pi with more features, you can upgrade to any of the available models; the work you’ve done on the Zero will still function.

If you’re unsure about which model is best, know that you can’t go wrong with any of the models, and at their price points, even using the most expensive board for one or two projects does not result in a considerable loss of monetary investment. However, if you’re not sure how involved you’ll stay with your new project, then purchasing the $5.00 model is a safe way to go. If it ends up in the junk drawer after a few months, you’ve lost little more than time. But if you catch the Pi bug, any of your projects transfer to the more advanced models.

Pi Projects

Based on your experience (Newbie, Computer Comfortable, or Old Hand), let’s discuss the available projects. Keep in mind that this list is not the end-all and be-all of its potential. The tasks and projects that you take on will increase in difficulty, intricacy, and complexity as your knowledge and confidence grow.

At the Newbie level, projects that introduce you to coding and circuits are perfect beginner-level projects. Such projects include controlling LED lights, creating a digital picture frame, building personal cloud storage, learning Scratch to code a game, making an alarmed motion sensor, and having music play automatically when you enter a room.

Projects for the Computer Comfortable include building an RFID attendance system, setting up a network scanner, building a digital clock, building a quiz game with buzz controllers, building a twitter bot, building a webcam server, and utilizing a Raspberry Pi email server using Citadel.

If the above projects are too basic for the Old Hand in you, you can try an advanced project that puts your coding and engineering skills to use. For example, build a robot that you program and control remotely, make a handheld console for a video game, create a laptop for your Raspberry Pi, build a smart CCTV system that recognizes friends and family, or develop and build a home security system.

Each project you attempt gives you the chance to practice what you have learned and build on that knowledge. Whether your ultimate goal is an off-the-grid smart home or just an understanding of computer coding, Raspberry Pi grows with you without being left to your own devices. The Raspberry Pi Foundation has video tutorials, blogs, community rooms, and lesson plans available to anyone through their website. Volunteers across the country run Raspberry Jams (meet-ups for creating with Raspberry Pi), Coder Dojos (coding club for youth 7 to 17), and in-school Code Clubs run as extracurricular activities at public schools (youth 9 to 13).

In short, Raspberry Pi, whatever model you go with, is a valuable tool to learn coding and computer science. Specialized equipment is needed, depending on the task you’re attempting, but the essential equipment is readily and economically available. The application possibilities of Raspberry Pi grows with you, becoming more robust and technologically advanced as your knowledge, skill, and confidence grow. With a minimal investment, Raspberry Pi is an incredible tool to promote and encourage computer science exploration and worthy of your time. Feed your curiosity and give Raspberry Pi a try.


What is a Raspberry Pi and How Does it Work?

In the 1970s, the information age began. From the largest supercomputers to the smallest home desktops, this period brought with it the ability to access information at the touch of a button or click of a mouse. Advances in technology have reduced computers from behemoths stored in large warehouses to devices you can carry in your pocket or wear on your wrist. Today you would be hard-pressed to find a business or industry that does not use computer technology in one form or another.

While the benefits of computer technology are extensive, the disparity it leaves between classes and economies is hard to ignore. Countries that cannot afford the infrastructure required to use advancing technology continue to fall behind countries that can. People without access to basic computing skills fail to keep up with advancements and find themselves falling behind their peers. Students, young and old, who lack access can find their education stunted. In short, lack of knowledge of technology, and the inability to navigate the information superhighway widens the chasm between the haves and the have-nots.

The Raspberry Pi Foundation looks to bridge the gap by providing an economically friendly way to learn beginning programming languages. In 2012, the Foundation launched Raspberry Pi, a single-board computer designed to teach programming skills, build hardware projects, do home automation, and explore industrial applications of computer technology. An economical computer – $55.00 or less – it runs Linux (a computer operating system) and provides general-purpose input and output (GPIO) pins that allow the user to control electronic components for physical computing and exploring the Internet of Things (IoT).

Founded in the United Kingdom in 2009, the Raspberry Pi Foundation promotes the study of basic computer science in schools with a single-board computer called Raspberry Pi. One of the founders of Raspberry Pi, Eben Upton, created the first Raspberry Pi in an attempt to solve the problem of a dwindling student population in computing science at the University of Cambridge. The simplicity and ease of access led Raspberry Pi to become the UK’s best-selling personal computer, selling over two million units within two years of production, while encouraging everyone with interest to study and play. Sales from Raspberry Pi products fund charitable work that promotes the understanding of computers and the use of technology in education and developing countries. Raspberry Pi is available throughout the world through the Foundation’s website and in select countries through approved Pi Resellers.

The operating system for all Raspberry Pi products is Linux. Linux is an open-source operating system that interfaces between the computer’s hardware and software programs. The language used with Raspberry Pi is Python – a general-purpose and high-level programming language used to develop graphical user interface (GUI) applications, websites, and web applications. One of the benefits of Raspberry Pi is that it is not necessary to have an intimate knowledge of Linux or Python before beginning a project with Raspberry Pi. In fact, the purpose of the product is to teach the system and language through engaging projects.

The most basic model is the Raspberry Pi Zero or Raspberry Pi Zero W – the Zero W comes with WiFi and Bluetooth capabilities while the Zero does not. The basic model provides the user the opportunity to learn the computer language and explore the Internet of Things (IoT) with projects designed to keep the learner engaged. The IoT is a system that consists of interrelated computing devices and mechanical and digital machines providing the ability to transfer data over a network. Using Raspberry Pi Zero, you can undertake projects such as word clocks, environmental monitors (temperature, humidity, etc.), airplay speakers, informational displays, drones, retro games, and selfiebots.

With each project that you complete, you gain knowledge and skills that increase your ability and confidence. When you outgrow the Zero, move up to the next model. Each version of the Raspberry Pi integrates new user functions such as USB ports, a media center, and a smart home hub. Use the Raspberry Pi’s later versions to build your home security system, run dual HD monitors, and build a home theater PC. The projects and applications for Raspberry Pi are limited only by your curiosity and desire to learn.

One of the most impressive aspects of Raspberry Pi is the amount and variety of support available to users of Raspberry Pi. The Foundation website contains forums, projects, blogs, help guides, videos, and troubleshooting guides. The website is an excellent resource for the self-motivated individual learner, parents, and teachers, and presents the information in an easy-to-grasp format. In addition to the website resources, the support for educators is extensive. From online training courses to magazines, curriculum, and face-to-face academies, the Foundation has ensured that educators have the tools necessary to lead students through the fascinating discovery of computer technology. Live groups and community events are an important part of Raspberry Pi. Groups include CoderDojos for young people (ages 7 to 17), school-based Code Clubs (ages 9 to 13), and Raspberry Jams (meetups for people of all ages). The events and groups are growing in popularity throughout the world, with volunteers (old and young), leading participants through discovery, problem-solving, coding, and building Raspberry Pi projects. Competitions and events also take place throughout the year that stimulates learning and encourages collaboration, creativity, and real-world problem-solving.

Raspberry Pi may not make someone the next Steve Jobs, but it will open up a world of possibilities. Computers, whether we like it or not, are an integral part of our society. They connect us and allow us to grow and learn while increasing independence, efficiency, and a sense of purpose. Raspberry Pi brings the out-of-reach to our fingertips with accessible, user-friendly technology. Coding and programming may not be for everyone, but it is available for everyone to try. Learn a new language, build a computer, and taste the internet of things with a small piece of Raspberry Pi.