The Raspberry Pi
started out as an initiative to make
programming accessible to people
that do not have a lot of money to spend
on computers and software.
The idea was to create a low-cost
educational computing platform
to allow anyone to learn computer programming.
When the first Raspberry Pi
was launched, it became an instant hit as
it offered a means of building a cheap
multimedia server.
Since then the Raspberry Pi has evolved
quite a bit and several million boards
have been sold worldwide.
So if the Raspberry Pi is not a pastry,
then what exactly is it?
The Raspberry Pi is a single board
computer, which means that it can
function without any external
peripherals like a keyboard or a monitor.
But it is also powerful enough to be
used as a computer to do for instance
the word processing on.
Because the Raspberry Pi can work
standalone and is inexpensive, it is a
great board to put in a box
and use it for one specific task like a
multimedia server or as the brains for a
robot or a drone.
For this reason the Raspberry Pi has
been adopted by both hobbyists and professionals,
and it has found its way into many
different projects and products.
Contrary to commercial laptop computers
that usually run
Windows or Mac OS,
the Raspberry Pi runs Raspberry Pi OS,
a flavor of Linux.
However, the operating system is not pre-installed
and there are many other operating systems that can be used instead.
For instance Android, Windows 10 IoT OpenElec and LibreElec
and Ubuntu and many more all run on the
Raspberry Pi.
The multimedia server was probably the
application that laid the foundations
for the success of the Raspberry Pi
as it generated a huge demand for boards.
Education was its original destination
and students all over the world now use the board.
Many people build retro gaming arcades
with the Pi while others, like me,
use it in home automation.
Controlling robots and drones is also popular,
but it is its usefulness for hobby projects
that attracts more and more
users.
Compared to a laptop computer the
Raspberry Pi is special in that it has
no enclosure and lacks a few more things
that you would expect, like
for instance a power button.
Its hard disk is a microSD card on the backside.
This is quite practical as you can
reconfigure a Raspberry Pi simply
by replacing the microSD card,
but it also makes the system a bit slow
and unreliable as SD cards break easily.
The Raspberry Pi has the same dimensions
as a credit card even though it seems
much bigger, because it's about
20 times thicker.
The heart of the Raspberry Pi is a powerful chip from Broadcom,
similar to those found in smartphones. It
has dual-band Wi-Fi and Bluetooth Low Energy,
Ethernet, USB 3.0, up to 8 gigabytes of memory and a USB-C-based power supply.
The Raspberry Pi features gigabit Ethernet and USB 2.0 and USB 3.0 communication ports.
It has a combined audio/video connector,
a camera connector,
two HDMI ports and a display port.
Last but not least is the 40-pin extension connector
that can be used to plug add-on boards on
or to connect to home-brew hardware.
The camera connector is popular as it allows the Raspberry Pi to see.
With the Pi getting more powerful with each new model,
the cameras that can be used become better too.
This brings us to the different
Raspberry Pi models that are around.
Today they can be divided into four
groups:
Model A, Model B, the Zero and Compute Modules.
The type on the upper left is the original Raspberry Pi and this shape has been abandoned.
The Raspberry Pi Model A is the second
board that was released.
Model B came first. Model A does not have
Ethernet and it has only one USB port.
The extension connector has 26 pins
and the audio and video outputs have individual connectors.
Model A evolved to become the A+, which is smaller.
This has become the actual Model A shape
with its 40-pin extension connector
a microSD card and combined audio/video connector.
There has not been a Raspberry Pi 2 Model A or A+,
and today the Raspberry Pi 3 Model A+
is the latest Model A board.
It now has Wi-Fi and Bluetooth.
The first Raspberry Pi that was launched
was the Model B.
It has Ethernet and two USB ports.
Model B quickly became Model B+, which,
like Model A+, is smaller
and has a 40-pin extension connector,
a microSD card on its backside, and a
combined audio/video connector.
The Raspberry Pi 2 Model B has a more
powerful processor
and more memory than the previous Model B+.
Instead of a Raspberry Pi 2 Model B+,
an update was released which became
known as Raspberry Pi 2 Model B version 1.2.
It has a slightly more
powerful processor than version 1.
With the introduction of the Raspberry
Pi 3, wireless connectivity was added to the Pi.
This model also is a bit faster and has a better power supply,
which had always been a weak point of the previous models.
Besides offering a bit more processing power,
the Raspberry Pi 3 Model B+ also features gigabit Ethernet and dual-band Wi-Fi.
At the time of recording this video the 
Raspberry Pi 4 Model B was the most
recent model.
It presents a major update compared to
the previous models as that it is
no longer fully compatible on the connector
side.
The micro USB power connector has been
replaced by a USB-C connector
and the full-size HDMI connector was
split into two micro HDMI ports.
The Ethernet and USB connectors
swapped places.
It is also much more powerful with up to 8 GB of RAM, real gigabit Ethernet and two USB 3.0 ports.
The board is available with three different memory sizes: 2 GB, 4 GB and 8 GB.
To allow easier embedding of the
Raspberry Pi into user applications,
the Raspberry Pi zero board was released.
This is a small stripped-down Model A
and is very cheap as it only costs $5.
The Zero-W is a Zero with Wi-Fi and Bluetooth.
When you add a 40-pin header to the Zero-W, you get a Zero-WH.
Finally there is the Compute Module or
CM series.
These modules only have a processor and
memory and no peripherals,
and they fit into a SODIMM socket.
They are intended for embedding in user applications,
and the current model is the CM3+.
So what do you need to get started?
Well, first of all, you will need a Raspberry Pi 4 Model B
unless you have a good reason for wanting another model.
Add to this a microSD card of 8 GB or bigger to install the operating system on.
A 15-watt USB-C power supply is required
to power the system,
and very practical but not required is
some sort of display with HDMI input.
Keep in mind that it must connect to one
of the micro HDMI ports on the Pi
so an adapter or special cable may be
required too.
Finally, although strictly speaking they
are optional,
a keyboard and a mouse will prove to be very handy too.
Once the system is complete, you must
install Raspberry Pi OS on the microSD
card.
With the introduction of the Raspberry
Pi Imager tool this has become simple as
long as you have a good internet
connection.
Download the tool from the Raspberry Pi
website and install it on a computer.
Stick the microSD card into the
computer and launch the Imager tool.
Select Raspberry Pi OS from the list and
select your microSD card,
and then click 'Write'.
The tool will now
download the OS
and write it to the microSD card.
This takes quite a while, especially if your internet connection is slow.
Note that you have to download it only once,
so rewriting the microSD card or
preparing more cards is a bit faster.
When sticking the microSD card into the
Pi's card holder,
make sure that the card's contacts face
the Raspberry Pi's backside.
Connect the keyboard and the mouse.
Also connect the display.
Either one of the HDMI ports will work,
even though HDMI-0 is recommended for some reason.
Finally, connect the power supply.
When you power the board for the first time
the operating system will have to do
some extra work, making the boot process
a bit slower.
The screen will blink and flicker a few times; this is normal.
The boot process is complete when you see a nice graphical desktop appear.
This brings us to the final preparation step: system configuration.
A wizard will guide you through this.
It will ask for the language and keyboard you want to use and it lets you set up Wi-Fi.
Once an internet connection has been established
the wizard proposes to
update the system.
If you accept it, you may be in for a
long wait,
especially if your internet connection is slow.
When the wizard is done, you will be
asked to restart your system to apply the new settings.
When the Raspberry Pi is rebooted you are ready to go!
