A Raspberry Pi aka RasPi is what is commonly referred to as a SoC aka System on a Chip, again fancy tech speak for basically having all computer components in a tiny package. It is the exact same thing they use in smartphones to give them a lot of resources, without using too much power and while remaining small. The RasPi was actually a university project at first, to use low cost surplus smartphone components to make small computers for 3rd world countries. It however quickly became popular with a lot of hobbyists in 1st world countries and ended up being put in everything from homemade laptops, to fridges and on to kids toys.
The most remarkable thing about RasPi though, is that it has kept is price of $50 for this tiny little computer, even as time passed and they got more and more powerful. Today the latest release of the RasPi, namely the Raspberry Pi 4B+ is actually powerful enough to run like a computer with two screens. It’s not powerful enough just yet for it to do some serious gaming, but it can run a browser, some Word documents and some basic games without too many hickups.
Where most people trip up with it though, is that it seems to be pretty hard to get into working with a RasPi, especially considering that most projects with it has to do with building robots of some sort. It is however easier than setting up a brand new computer in most cases, the Raspberry Pi site has a very easy to follow guide on how to flash a new Operating System aka OS (fancy tech speak for program that runs other programs) on it.
As for using a RasPi, I very much recommend reading my article on how to get started with linux, although Linux is not the only thing it can run, it is the most common and well supported Operating System. I will say one thing this has over a Linux Computer though, due to it’s low price, it is most likely going to be bought as a hobby or a toy, so it is perfect for taking risks and trying new things, as a reset is just one flash away.
The thing that makes the RasPi the most exciting though is all those little metal pins seen at the top of the board, they are called I/O pins. This is yet another set of fancy tech speak for I = input and O = output, what this really means though, is that you can connect components to them and make them do things. The RasPi also gets sold with a bunch of components called hats, it is not fancy tech speak, it’s just because they sit on top of it and they thought it would be funny to call them hats. They will usually extend what a RasPi can do, like interfacing with retro computers, adding batteries to run the RasPi off, onto screens, buttons and a myriad of other things.
This all being said though, if you want, you can also just put a desktop version of Linux on it, connect it to a screen and a keyboard to get a small computer in your kitchen, bathroom or workshop.