This chapter introduces Raspberry Pi and the process of setting it up for the first time. We will connect Raspberry Pi to a suitable display, power, and peripherals. We will install an operating system on an SD card. This is required for the system to boot. Next, we will ensure that we can connect successfully to the internet through a local network.

Finally, we will make use of the network to provide ways to remotely connect to and/or control Raspberry Pi from other computers and devices, as well as to ensure that the system is kept up to date.

Once you have completed the steps within this chapter, your Raspberry Pi will be ready
for you to use for programming. If you already have your Raspberry Pi set up and running, ensure that you take a look through the following sections, as there are many helpful tips.

The Raspberry Pi is a single-board computer created by the Raspberry Pi Foundation, a charity formed with the primary purpose of re-introducing low-level computer skills to children in the UK. The aim was to rekindle the microcomputer revolution of the 1980s, which produced a whole generation of skilled programmers.

Even before the computer was released at the end of February 2012, it was clear that Raspberry Pi had gained a huge following worldwide and, at the time of writing this book, has sold over 10 million units. The following image shows several different Raspberry Pi models:

The name, Raspberry Pi, was a combination of the desire to create an alternative computer with a fruit-based name (such as Apple, BlackBerry, and Apricot) and a nod to the original concept of a simple computer that could be programmed using Python (shortened to Pi).

In this book, we will take this little computer, find out how to set it up, and then explore its capabilities chapter by chapter, using the Python programming language.

It is often asked, "Why has Python been selected as the language to use on Raspberry Pi?" The fact is that Python is just one of the many programming languages that can be used on Raspberry Pi.

There are many programming languages that you can choose, from high-level graphical block programming, such as Scratch, to traditional C, right down to BASIC, and even the raw machine code assembler. A good programmer often has to be code multilingual to be able to play to the strengths and weaknesses of each language to best meet the needs of their desired application. It is useful to understand how different languages (and programming techniques) try to overcome the challenge of converting what you want into what you get, as this is what you are trying to do as well while you program.

Python has been selected as a good place to start when learning about programming, as it provides a rich set of coding tools while still allowing simple programs to be written without fuss. This allows beginners to gradually be introduced to the concepts and methods on which modern programming languages are based without requiring them to know it all from the start. It is very modular with lots of additional libraries that can be imported to quickly extend the functionality. You will find that, over time, this encourages you to do the same, and you will want to create your own modules that you can plug into your own programs, thus taking your first steps into structured programming.

Python addresses formatting and presentation concerns. As indentation will add better readability, indents matter a lot in Python. They define how blocks of code are grouped together. Generally, Python is slow; since it is interpreted, it takes time to create a module while it is running the program. This can be a problem if you need to respond to time-critical events. However, you can precompile Python or use modules written in other languages to overcome this.

It hides the details; this is both an advantage and a disadvantage. It is excellent for beginners but can be difficult when you have to second-guess aspects such as datatypes. However, this in turn forces you to consider all the possibilities, which can be a good thing.

A massive source of confusion for beginners is that there are two versions of Python on Raspberry Pi (Version 2.7 and Version 3.6), which are not compatible with each other, so code written for Python 2.7 may not run with Python 3.6 (and vice versa).

The Python Software Foundation is continuously working to improve and move forward with the language, which sometimes means they have to sacrifice backward compatibility to embrace new improvements (and, importantly, remove redundant and legacy ways of doing things).

Essentially, the selection of which version to use will depend on what you intend to do. For instance, you may require Python 2.7 libraries, which are not yet available for Python 3.6. Python 3 has been available since 2008, so these tend to be older or larger libraries that have not been translated. In many cases, there are new alternatives to legacy libraries; however, their support can vary.

In this book, we have used Python 3.6, which is also compatible with Python 3.5 and 3.3.

Since its release, Raspberry Pi has come in various iterations, featuring both small and large updates and improvements to the original Raspberry Pi Model B unit. Although it can be confusing at first, there are three basic types of Raspberry Pi available (and one special model).

The main flagship model is called Model B. This has all the connections and features, as well as the maximum RAM and the latest processor. Over the years, there have been several versions, most notably Model B (which had 256 MB and then 512 MB RAM) and then Model B+ (which increased the 26-pin GPIO to 40 pins, switched to using a microSD card slot, and had four USB ports instead of two). These original models all used the Broadcom BCM2835 system on chip (SOC), consisting of a single core 700 MHz ARM11 and VideoCore IV graphical processing unit (GPU).

The release of Raspberry Pi 2 Model B (also referred to as 2B) in 2015 introduced a new Broadcom BCM2836 SOC, providing a quad-core 32-bit ARM Cortex A7 1.2 GHz processor and GPU, with 1 GB of RAM. The improved SOC added support for Ubuntu and Windows 10 IoT. Finally, we had the latest Raspberry Pi 3 Model B, using another new Broadcom BCM2837 SOC, which provides a quad-core 64-bit ARM Cortex-A53 and GPU, alongside on-board Wi-Fi and Bluetooth.

Model A has always been targeted as a cut-down version. While having the same SOC as Model B, there are limited connections consisting of a single USB port and no wired network (LAN). Model A+ again added more GPIO pins and a microSD slot. However, the RAM was later upgraded to 512 MB of RAM and again there was only a single USB port/no LAN. The Broadcom BCM2835 SOC on Model A has not been updated so far (so is still a single core ARM11); however, a Model 3A (most likely using the BCM2837).

The Pi Zero is an ultra-compact version of Raspberry Pi intended for embedded applications where cost and space are a premium. It has the same 40-pin GPIO and microSD card slot as the other models, but lacks the on-board display (CSI and DSI) connection. It does still have HDMI (via a mini-HDMI) and a single micro USB on-the-go (OTG) connection. Although not present in the first revision of the Pi Zero, the most recent model also includes a CSI connection for the on-board camera.

The special model is known as the compute module. This takes the form of a 200-pin SODIMM card. It is intended for industrial use or within commercial products, where all the external interfaces would be provided by a host/motherboard, into which the module would be inserted. Example products include the Slice Media Player (http://fiveninjas.com) and the OTTO camera. The current module uses the BCM2835, although an updated compute module (CM3).

The Raspberry Pi Wikipedia page provides a full list of the all different variants and their specifications:
https://en.wikipedia.org/wiki/Raspberry_Pi#Specifications

Also, the Raspberry Pi product page gives you the details about the models available and the accessories' specifications:
https://www.raspberrypi.org/products/

All sections of this book are compatible will all current versions of Raspberry Pi, but Model 3B is recommended as the best model to start with. This offers the best performance (particularly useful for the GPU examples in Chapter 7, Creating 3D Graphics, and the OpenCV examples used in Chapter 6, Detecting Edges and Contours in Images), lots of connections, and built-in Wi-Fi, which can be very convenient.

Pi Zero is recommended for projects where you want low power usage or reduced weight/size but do not need the full processing power of Model 3B. However, due to its ultra-low cost, Pi Zero is ideal for deploying a completed project after you have developed it.

There are many ways to wire up Raspberry Pi and use the various interfaces to view and control content. For typical use, most users will require power, display (with audio), and a method of input such as a keyboard and mouse. To access the internet, refer to the Networking and connecting your Raspberry Pi to the internet via the LAN connector or Using built-in Wi-Fi and Bluetooth on Raspberry Pi recipes.

Before you can use your Raspberry Pi, you will need an SD card with an operating system installed or with the New Out Of Box System (NOOBS) on it, as discussed in the Using NOOBS to set up your Raspberry Pi SD card recipe.

The following section will detail the types of devices you can connect to Raspberry Pi and, importantly, how and where to plug them in.

As you will discover later, once you have your Raspberry Pi set up, you may decide to connect remotely and use it through a network link, in which case you only need power and a network connection. Refer to the following sections: Connecting remotely to Raspberry Pi over the Network using VNC and Connecting Remotely to Raspberry Pi over the Network using SSH (and X11 Forwarding).

The layout of Raspberry Pi is shown in the following diagram:

More information about the preceding figure is listed as follows:

• Display: The Raspberry Pi supports the following three main display connections; if both HDMI and composite video are connected, it will default to HDMI only:
  • HDMI: For best results, use a TV or monitor that has an HDMI connection, thus allowing the best resolution display (1080p) and also digital audio output. If your display has a DVI connection, you may be able to use an adapter to connect through the HDMI. There are several types of DVI connection; some support analogue (DVI-A), some digital (DVI-D), and some both (DVI-I). Raspberry Pi is only able to provide a digital signal through the HDMI, so an HDMI-to-DVI-D adapter is recommended (shown with a tick mark in the following screenshot). This lacks the four extra analogue pins (shown with a cross mark in the following screenshot), thus allowing it to fit into both DVI-D and DVI-I type sockets:

If you wish to use an older monitor (with a VGA connection), an additional HDMI-to-VGA converter is required. Raspberry Pi also supports a rudimentary VGA adaptor (VGA Gert666 Adaptor), which is driven directly off of the GPIO pins. However, this does use up all but four pins of the 40-pin header (older 26-pin models will not support the VGA output):

• • Analogue: An alternative display method is to use the analogue composite video connection (via the phono socket); this can also be attached to an S-Video or European SCART adapter. However, the analogue video output has a maximum resolution of 640 x 480 pixels, so it is not ideal for general use:

When using the RCA connection or a DVI input, audio has to be provided separately by the analogue audio connection. To simplify the manufacturing process (by avoiding through-hole components), the Pi Zero does not have analogue audio or an RCA socket for analogue video (although they can be added with some modifications):

• • Direct Display DSI: A touch display produced by Raspberry Pi Foundation will connect directly into the DSI socket. This can be connected and used at the same time as the HDMI or analogue video output to create a dual display setup.
• Stereo analogue audio (all except Pi Zero): This provides an analogue audio output for headphones or amplified speakers. The audio can be switched via Raspberry Pi configuration tool on the desktop between analog (stereo socket) and digital (HDMI), or via the command line using amixer or alsamixer.

• Network (excluding models A and Pi Zero): The network connection is discussed in the Networking and connecting your Raspberry Pi to the internet via the LAN connector recipe later in this chapter. If we use the Model A Raspberry Pi, it is possible to add a USB network adapter to add wired or even wireless networking (refer to the Networking and connecting your Raspberry Pi to the internet via a USB Wi-Fi dongle recipe).
• Onboard Wi-Fi and Bluetooth (Model 3 B only): The Model 3 B has built-in 802.11n Wi-Fi and Bluetooth 4.1; see the Using the built-in Wi-Fi and Bluetooth on Raspberry Pi recipe.
• USB (1x Model A/Zero, 2x Model 1 B, 4x Model 2 B and 3 B): Using a keyboard and mouse:
  • Raspberry Pi should work with most USB keyboards and mice. You can also use wireless mice and keyboards, which use RF dongles. However, additional configuration is required for items that use the Bluetooth dongles.
  • If there is a lack of power supplied by your power supply or the devices are drawing too much current, you may experience the keyboard keys appearing to stick, and, in severe cases, corruption of the SD card.

• • Debian Linux (upon which Raspbian is based) supports many common USB devices, such as flash storage drives, hard-disk drives (external power may be required), cameras, printers, Bluetooth, and Wi-Fi adapters. Some devices will be detected automatically, while others will require drivers to be installed.

• Micro USB power: The Raspberry Pi requires a 5V power supply that can comfortably supply at least 1,000 mA (1,500 mA or more is recommended, particularly with the more power-hungry Model 2 and Model 3) with a micro USB connection. It is possible to power the unit using portable battery packs, such as the ones suitable for powering or recharging tablets. Again, ensure that they can supply 5V at 1,000 mA or over.

You should aim to make all other connections to Raspberry Pi before connecting the power. However, USB devices, audio, and networks may be connected and removed while it is running, without problems.

In addition to the standard primary connections you would expect to see on a computer, Raspberry Pi also has a number of other connections.

Each of the following connections provides additional interfaces for Raspberry Pi:

• 20 x 2 GPIO pin header (Model A+, B+, 2 B, 3 B, and Pi Zero): This is the main 40-pin GPIO header of Raspberry Pi used for interfacing directly with hardware components. We use this connection in Chapters 6, Detecting Edges and Contours in Images, Chapter 7, Creating 3D Graphics, Chapter 9, Using Python to Drive Hardware, and Chapter 10, Sensing and Displaying Real-world Data. The recipes in this book are also compatible with older models of Raspberry Pi that have a 13 x 2 GPIO pin header.
• P5 8 x 2 GPIO pin header (Model 1 B revision 2.0 only): We do not use this in the book.
• Reset connection: This is present on later models (no pins fitted). A reset is triggered when Pin 1 (reset) and Pin 2 (GND) are connected together. We use this in the A controlled shutdown button recipe in Chapter 9, Using Python to Drive Hardware.
• GPU/LAN JTAG: The Joint Test Action Group (JTAG) is a programming and debugging interface used to configure and test processors. These are present on newer models as surface pads. A specialist JTAG device is required to use this interface. We do not use this in the book.
• Direct camera CSI: This connection supports Raspberry Pi Camera Module. Note that the Pi Zero has a smaller CSI connector than the other models, so it requires a different ribbon connector.
• Direct Display DSI: This connection supports a directly connected display, such as a 7-inch 800 x 600 capacitive touch screen.

The Raspberry Pi requires the operating system to be loaded onto an SD card before it starts up. The easiest way to set up the SD card is to use NOOBS; you may find that you can buy an SD card with NOOBS already loaded on it.

NOOBS provides an initial start menu that provides options to install several of the available operating systems on to your SD card.

Since NOOBS creates a RECOVERY partition to keep the original installation images, an 8 GB SD card or larger is recommended. You will also need an SD card reader (experience has shown that some built-in card readers can cause issues, so an external USB type reader is recommended).

If you are using an SD card that you have used previously, you may need to reformat it to remove any previous partitions and data. NOOBS expects the SD card to consist of a single FAT32 partition.

If using Windows or macOS X, you can use the SD Association's formatter, as shown in the following screenshot (available at https://www.sdcard.org/downloads/formatter_4/):

From the Option Setting dialog box, set FORMAT SIZE ADJUSTMENT. This will remove all the SD card partitions that were created previously.

If using Linux, you can use gparted to clear any previous partitions and reformat it as a FAT32 partition.

The full NOOBS package (typically just over 1 GB) contains Raspbian, the most popular Raspberry Pi operating system image built in. A lite version of NOOBS is also available that has no preloaded operating systems (although a smaller initial download of 20 MB and a network connection on Raspberry Pi are required to directly download the operating system you intend to use).

NOOBS is available at http://www.raspberrypi.org/downloads, with the documentation available at https://github.com/raspberrypi/noobs.

By performing the following steps, we will prepare the SD card to run NOOBS. This will then allow us to select and install the operating system we want to use:

1. Get your SD card ready.
2. On a freshly formatted or new SD card, copy the contents of the NOOBS_vX.zip file. When it has finished copying, you should end up with something like the following screenshot of the SD card:

3. You can now put the card into your Raspberry Pi, connect it to a keyboard and display, and turn the power on. Refer to the Connecting to Raspberry Pi recipe for details on what you need, and how to do this.

By default, NOOBS will display via the HDMI connection. If you have another type of screen (or you don't see anything), you will need to manually select the output type by pressing 1, 2, 3, or 4, according to the following functions:

• Key 1 stands for the Standard HDMI mode (the default mode)
• Key 2 stands for the Safe HDMI mode (alternative HDMI settings if the output has not been detected)
• Key 3 stands for Composite PAL (for connections made via the RCA analogue video connection)
• Key 4 stands for Composite NTSC (again, for connections via the RCA connector)

This display setting will also be set for the installed operating system.

After a short while, you will see the NOOBS selection screen that lists the available distributions (the offline version only includes Raspbian). There are many more distributions that are available, but only the selected ones are available directly through the NOOBS system. Click on Raspbian, as this is the operating system being used in this book.

Press Enter or click on Install OS, and confirm that you wish to overwrite all the data on
the card. This will overwrite any distributions previously installed using NOOBS but will not remove the NOOBS system; you can return to it at any time by pressing Shift when you turn the power on.

It will take around 20 to 40 minutes to write the data to the card depending on its speed. When it completes and the Image Applied Successfully message appears, click on OK, and Raspberry Pi will start to boot into Raspberry Pi Desktop.

The purpose of writing the image file to the SD card in this manner is to ensure that the SD card is formatted with the expected filesystem partitions and files required to correctly boot the operating system.

When Raspberry Pi powers up, it loads some special code contained within the GPU's internal memory (commonly referred to as binary blob by Raspberry Pi Foundation). The binary blob provides the instructions required to read the BOOT partition on the SD card, which (in the case of a NOOBS install) will load NOOBS from the RECOVERY partition. If at this point Shift is pressed, NOOBS will load the recovery and installation menu. Otherwise, NOOBS will begin loading the OS as specified by the preferences stored in the SETTINGS partition.

When loading the operating system, it will boot via the BOOT partition, using the settings defined in config.txt and options in cmdline.txt to finally load to the desktop on the root partition. Refer to the following diagram:

NOOBS allows the user to optionally install multiple operating systems on the same card and provides a boot menu to choose between them (with an option to set a default value in the event of a time-out period).

If you later add, remove, or re-install an operating system, ensure first that you make a copy of any files, including system settings you wish to keep, as NOOBS may overwrite everything on the SD card.

When you power up Raspberry Pi for the first time directly, the desktop will be loaded. You can configure the system settings using the Raspberry Pi Configuration menu (under the Preferences menu on the Desktop or via the sudo raspi-config command). With this menu, you can make changes to your SD card or set up your general preferences:

Ensure that you change the default password for the pi user account once you have logged in, as the default password is well known. This is particularly important if you connect to public networks. You can do this with the passwd command, as shown in the following screenshot:

This provides greater confidence because if you later connect to another network, only you will be able to access your files and take control of your Raspberry Pi.

To avoid any data corruption, you must ensure that you correctly shut down Raspberry Pi by issuing a shutdown command, as follows:

sudo shutdown -h now  

Or, use this one:

sudo halt  

You must wait until this command completes before you remove power from Raspberry Pi (wait for at least 10 seconds after the SD card access light has stopped flashing).

You can also restart the system with the reboot command, as follows:

sudo reboot  

An alternative to using NOOBS is to manually write the operating system image to the SD card. While this was originally the only way to install the operating system, some users still prefer it. It allows the SD cards to be prepared before they are used in Raspberry Pi. It can also provide easier access to startup and configuration files, and it leaves more space available for the user (unlike NOOBS, a RECOVERY partition isn't included).

The default Raspbian image actually consists of two partitions, BOOT and SYSTEM, which will fit into a 2 GB SD card (4 GB or more is recommended).

You need a computer running Windows/Mac OS X/Linux (although it is possible to use another Raspberry Pi to write your card; be prepared for a very long wait).

Download the latest version of the operating system you wish to use. For the purpose of this book, it is assumed you are using the latest version of Raspbian available at http://www.raspberrypi.org/downloads.

Perform the following steps depending on the type of computer you plan to use to write to the SD card (the .img file you need is sometimes compressed, so before you start, you will need to extract the file).

The following steps are for Windows:

1. Ensure that you have downloaded the Raspbian image, as previously detailed, and extracted it to a convenient folder to obtain an .img file.
2. Obtain the Win32DiskImager.exe file available at http://www.sourceforge.net/projects/win32diskimager.
3. Run Win32DiskImager.exe from your downloaded location.
4. Click on the folder icon and navigate to the location of the .img file and click on Save.
5. If you haven't already done so, insert your SD card into your card reader and plug it into your computer.
6. Select the Device drive letter that corresponds to your SD card from the small drop-down box. Double-check that this is the correct device (as the program will overwrite whatever is on the device when you write the image).

7. Finally, click on the Write button and wait for the program to write the image to the SD card, as shown in the following screenshot:

8. Once completed, you can exit the program. Your SD card is ready.

The following steps should work for the most common Linux distributions, such as Ubuntu and Debian:

1. Using your preferred web browser, download the Raspbian image and save it in a suitable place.
2. Extract the file from the file manager or locate the folder in the terminal and unzip the .img file with the following command:

unzip filename.zip  

3. If you haven't already done so, insert your SD card into your card reader and plug it into your computer.
4. Use the df -h command and identify the sdX identifier for the SD card. Each partition will be displayed as sdX1, sdX2, and so on, where X will be a, b, c, d, and so on for the device ID.
5. Ensure that all the partitions on the SD card are unmounted using the
   umount /dev/sdXn command for each partition, where sdXn is the partition being unmounted.
6. Write the image file to the SD card, with the following command:

sudo dd if=filename.img of=/dev/sdX bs=4M  

7. The process will take some time to write to the SD card, returning to the Terminal prompt when complete.
8. Unmount the SD card before removing it from the computer, using the following command:

umount /dev/sdX1  

The following steps should work for most of the versions of OS X:

1. Using your preferred web browser, download the Raspbian image and save it somewhere suitable.
2. Extract the file from the file manager or locate the folder in the terminal and unzip the .img file, with the following command:

unzip filename.zip  

3. If you haven't already done so, insert your SD card into your card reader and plug it into your computer.

4. Use the diskutil list command and identify the disk# identifier for the SD card. Each partition will be displayed as disk#s1, disk#s2, and so on, where # will be 1, 2, 3, 4, and so on, for the device ID.

5. Ensure that the SD card is unmounted using the unmountdisk /dev/diskX command, where diskX is the device being unmounted.
6. Write the image file to the SD card, with the following command:

sudo dd if=filename.img of=/dev/diskX bs=1M  

7. The process will take some time to write to the SD card, returning to the Terminal prompt when complete.
8. Unmount the SD card before removing it from the computer, using the
   following command:

unmountdisk /dev/diskX  

Refer to the following diagram:

A manually written image will be of a fixed size (usually made to fit the smallest-sized SD card possible). To make full use of the SD card, you will need to expand the system partition to fill the remainder of the SD card. This can be achieved using the Raspberry Pi Configuration tool.

Select Expand Filesystem, as shown in the following screenshot:

Windows and macOS X do not support the ext4 format, so when you read the SD card, only the File Allocation Table (FAT) partitions will be accessible. In addition, Windows only supports the first partition on an SD card, so if you've installed NOOBS, only the RECOVERY partition will be visible. If you've written your card manually, you will be able to access the BOOT partition.

The data partition (if you installed one via NOOBS) and the root partition are in ext4 format and won't usually be visible on non-Linux systems.

Access the partitions from Raspberry Pi. To view the currently mounted partitions, use df, as shown in the following screenshot:

To access the BOOT partition from within Raspbian, use the following command:

cd /boot/  

To access the RECOVERY or data partition, we have to mount it by performing the
following steps:

1. Determine the name of the partition as the system refers to it by listing all the partitions, even the unmounted ones. The sudo fdisk -l command lists the partitions, as shown in the following screenshot:

The following table shows the names of partitions and their meanings

If you have installed additional operating systems on the same card, the partition identifiers shown in the preceding table will be different.

2. Create a folder and set it as the mount point for the partition; for the RECOVERY partition, use the following command:

mkdir ~/recovery
sudo mount -t vfat /dev/mmcblk0p1 ~/recovery  

To ensure that they are mounted each time the system is started, perform the following steps:

1. Add the sudo mount commands to /etc/rc.local before exit 0. If you have a different username, you will need to change pi to match:

sudo nano /etc/rc.local
sudo mount -t vfat /dev/mmcblk0p1 /home/pi/recovery  

2. Save and exit by pressing Ctrl + X, Y, and Enter.

If you have to install additional operating systems on the same card, the partition identifiers shown here will be different.

You can use Win32 Disk Imager to make a full backup image of your SD card by inserting your SD card into your reader, starting the program, and creating a filename to store the image in. Simply click on the Read button instead to read the image from the SD card and write it to a new image file.

To make a backup of your system, or to clone to another SD card using Raspberry Pi, use the SD Card Copier (available from the desktop menu via the Accessories | SD Card Copier).

Insert an SD card into a card reader into a spare USB port of Raspberry Pi and select the new storage device, as shown in the following screenshot:

Before continuing, the SD Card Copier will confirm that you wish to format and overwrite the target device and, if there is sufficient space, make a clone of your system.

The dd command can similarly be used to back up the card, as follows:

• For Linux, replacing sdX with your device ID, use this command:

sudo dd if=/dev/sdX of=image.img.gz bs=1M  

• For OS X, replacing diskX with your device ID, use the following command:

sudo dd if=/dev/diskX of=image.img.gz bs=1M

• You can also use gzip and split to compress the contents of the card and split them into multiple files, if required, for easy archiving, as follows:

sudo dd if=/dev/sdX bs=1M | gzip -c | split -d -b 2000m - image.img.gz
  

• To restore the split image, use the following command:

sudo cat image.img.gz* | gzip -dc | dd of=/dev/sdX bs=1M  

The simplest way to connect Raspberry Pi to the internet is by using the built-in LAN connection on the Model B. If you are using a Model A Raspberry Pi, a USB-to-LAN adapter can be used (refer to the There's more... section of the Networking and connecting your Raspberry Pi to the internet via a USB Wi-Fi dongle recipe for details of how to configure this).

You will need access to a suitable wired network, which will be connected to the internet, and a standard network cable (with an RJ45 type connector for connecting to Raspberry Pi).

Many networks connect and configure themselves automatically using the Dynamic Host Configuration Protocol (DHCP), which is controlled by the router or switch. If this is the case, simply plug the network cable into a spare network port on your router or network switch (or wall network socket if applicable).

Alternatively, if a DHCP server is not available, you shall have to configure the settings manually (refer to the There's more... section for details).

You can confirm this is functioning successfully with the following steps:

1. Ensure that the two LEDs on either side of Raspberry Pi light up (the left orange LED indicates a connection and the green LED on the right shows activity by flashing). This will indicate that there is a physical connection to the router and that the equipment is powered and functioning.
2. Test the link to your local network using the ping command. First, find out the IP address of another computer on the network (or the address of your router, perhaps, often 192.168.0.1 or 192.168.1.254). Now, on the Raspberry Pi Terminal, use the ping command (the -c 4 parameter is used to send just four messages; otherwise, press Ctrl + C to stop) to ping the IP address, as follows:

sudo ping 192.168.1.254 -c 4

3. Test the link to the internet (this will fail if you usually connect to the internet through a proxy server) as follows:

sudo ping www.raspberrypi.org -c 4
  

4. Finally, you can test the link back to Raspberry Pi by discovering the
   IP address using hostname -I on Raspberry Pi. You can then use the ping command on another computer on the network to ensure it is accessible (using Raspberry Pi's IP address in place of www.raspberrypi.org). The Windows version of the ping command will perform five pings and stop automatically, and will not need the -c 4 option.

If the aforementioned tests fail, you will need to check your connections and then confirm the correct configuration for your network.

If you find yourself using your Raspberry Pi regularly on the network, you won't want to have to look up the IP address each time you want to connect to it.

On some networks, you may be able to use Raspberry Pi's hostname instead of its IP address (the default is raspberrypi). To assist with this, you may need some additional software, such as Bonjour, to ensure hostnames on the network are correctly registered. If you have macOS X, you will have Bonjour running already.

On Windows, you can either install iTunes (if you haven't got it), which also includes the service, or you can install it separately (via the Apple Bonjour Installer available from https://support.apple.com/kb/DL999). Then you can use the hostname, raspberrypi or raspberrypi.local, to connect to Raspberry Pi over the network. If you need to change the hostname, then you can do so with the Raspberry Pi configuration tool, shown previously.

Alternatively, you may find it helpful to fix the IP address to a known value by manually setting the IP address. However, remember to switch it back to use DHCP when connecting to another network.

Some routers will also have an option to set a Static IP DHCP address, so the same address is always given to Raspberry Pi (how this is set will vary depending on the router itself).

Knowing your Raspberry Pi's IP address or using the hostname is particularly useful if you intend to use one of the remote access solutions described later on, which avoids the need for a display.