CSE 522S: Studio 2

Raspberry Pi Setup

"It's a dangerous business, Frodo, going out of your door. You step into the road, and if you don't keep your feet, there is no knowing where you might be swept off to."

—Bilbo, The Fellowship of the Ring by J. R. R. Tolkien, Book 1, Chapter 3

The aim of this studio to to set up your Raspberry Pi. We understand that your situation may be unique this semester, so this studio will be structured a little differently than others. We understand that you may not have access to a monitor, keyboard, and mouse, so we will provide optional instructions for headless setup of your Raspberry Pi, so you can access and control it from a laptop or desktop. Throughout this studio, we will be providing variant instructions based on the equipment and networks you have access to. In many places, you will be prompted to click on a header, which will expand the instructions relevant to your situation.

In this studio, you will:

1. Set up your Raspberry Pi
2. Boot, log into, and explore different configuration settings of the Raspberry Pi OS (previously called Raspbian).
3. Install the kernel you compiled on day 1 to run on your Raspberry Pi.

Please complete the required exercises below, as well as any optional enrichment exercises that you wish to complete. We encourage you to please work in groups of 2 or 3 people on each studio (and the groups are allowed to change from studio to studio) though if you would prefer to complete any studio by yourself that is allowed.

As you work through these exercises, please record your answers, and when you finish them each and every person who worked on them should please log into Canvas, select this course in this semester, and then upload a file containing them and also upload any other files the assignment asks for, and submit those files for this studio assignment (there should be a separate submission from each person who worked together on them).

Make sure that the name of each person who worked on these exercises is listed in the first answer, and make sure you number each of your responses so it is easy to match your responses with each exercise.

Required Exercises

1. As the answer to the first exercise, list the names of the (ideally 2 or 3) people who have worked together on this studio.

2. We would like to get a sense of which Raspberry Pi model each person is using this semester. As the answer to this exercise, please list, for each person in your group, the Raspberry Pi model (e.g. Model 3B+, Model 4B) that you have obtained for this class. We understand that you may be sharing a single Raspberry Pi among multiple people, and so there may be one or more group members who do not yet have a Raspberry Pi.

3. To start, you need to assemble your Raspberry Pi. If you have the recommended starter kit from Canakit, watching the video that you can find in the course's Canvas site on the "Setting up your Raspberry Pi" page of the "Intro to Linux and the Raspberry Pi" module before you start may help you with the assembly. To avoid problems: make sure you put the Raspberry Pi card into the protective case, before you install the heat sinks and MicroSD card that were provided in the kit (this helps with their alignment, and also avoids potential issues with damage to them or shearing them off as you're putting the card into the case).

   As the answer to this exercise, please let us know whether or not you ran into any surprises, concerns, questions, or issues during the assembly, and if you did what those were.

4. Now you are ready to install the Raspberry Pi OS.

   First, please specify how you will connect your Raspberry Pi to a network:
   A wired network connection with an Ethernet cable.
   Your own WiFi network.
   Washington University's WiFi network.

   Now, please specify how you will set up your Raspberry Pi:
   You have a monitor, keyboard, and mouse to connect to your Raspberry Pi.
   You do not have a monitor, keyboard, and mouse, or would otherwise like to perform a headless setup of your Raspberry Pi.

   You can follow these directions to set up and boot into the default Raspberry Pi OS (previously called Raspbian) distribution, which is what we will be using in this course.

   Another important tip to avoid problems: make sure you set the language to US English and the keyboard to US before beginning installation.

   Note that if you run into problems later (e.g., when trying the optional enrichment exercise) and are completely shut out of your Raspberry Pi, you can re-image it by shutting it down, starting it back up, and holding down the shift key when it says to do so. Doing this will repeat the installation, destroying the image that was already there (and forcing you to repeat the prior steps), but gives you a way to recover to this initial starting point.

   Please note that Washington University's WiFi network uses additional authentication measures that make a headless setup very difficult. It requires you to boot your Raspberry Pi before connecting it to the network. As such, please consider doing the standard setup with monitor, keyboard, and mouse. If this is not an option for you, please let your instructors know.

   The headless setup allows you to configure your Raspberry Pi without a monitor, keyboard, or mouse. You will use your existing laptop or desktop to write an OS image to your Raspberry Pi's MicroSD card, then write additional files to connect it to your wireless network and enable SSH. From there, you will be able to boot your Raspberry Pi, and connect to it from your laptop or desktop. At this time, we are providing instructions for Windows, MacOS, and Ubuntu Linux (Desktop version 20.04). This procedure additionally assumes you have the recommended starter kit from Canakit.

   Please select the appropriate OS for your laptop or desktop:
   Windows.
   MacOS.
   Ubuntu Linux.

   1. First, you will write the Raspberry Pi OS to the included MicroSD card.
      Insert the MicroSD card into the USB adapter, and connect it to a USB port on your computer.

   2. Download, install, and run the Raspberry Pi Imager:

      Windows Installer

      MacOS

      If you are using Ubuntu, you may download the .deb package

      If the .deb package fails to install, you may issue the following command instead: sudo snap install rpi-imager

      You can run the installed package by issuing the command: sudo rpi-imager.

      If you receive the error: mkdir: cannot create directory 'run/user/0' then run the following commands:

      cd /run/user

      sudo mkdir 0

      sudo chmod 0700 0

      If you receive an error like: Could not connect to any X display
      then run the following command: xhost +SI:localuser:root

   3. If the Raspberry Pi Imager is running successfully, proceed with the following steps:

      Select CHOOSE OS, then select Raspberry Pi OS (32-bit)

      Now, select CHOOSE SD CARD, and select the MicroSD card that you inserted. Make sure you select the correct card, as this will delete all existing data on the device!

      Finally, click WRITE. Once the write has completed, you will see a message box saying "Write Successful." You should now see a mounted volume labeled "boot."

      If you do not see the volume, or it shows as inaccessible or empty, you may need to remove and reinsert the SD card. You can also select the "CHOOSE SD CARD" option again in the Raspberry Pi Imager software to see where it is mounted.

      In Windows, Explorer may not name the drive correctly. However, the drive letter listed by the Raspberry Pi Imager software is the correct volume.

      The next steps will require you to create two files on this drive. Windows, by default, hides file extensions, which might cause the files to be named incorrectly.

      To fix this, first open Control Panel. Make sure the "View by:" option is set to Small or Large icons, instead of Category.

      Next, click on "File Explorer Options" (if you are using an older version of Windows, this may be called "Folder Options" instead.)

      Click the View tab, then uncheck the option: "Hide extensions for known file types"

      Click OK to apply your changes.

      In Ubuntu, you can use the df command to see where it is mounted; it will likely be at /media/<username>/boot

      On a Mac running MacOS 10.15.5, it was mounted at /Volumes/boot

   4. Now, you will need to create a file to allow your Raspberry Pi to automatically connect to your WiFi network.

      Create a file in the root of the "boot" volume named wpa_supplicant.conf with the following contents:

      ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
      update_config=1
      country=US
      
      network={
      	ssid="<WiFi Network Name>"
      	psk="<WiFi Network Password>"
      }
      	

   5. Next, you will need to create a file that enables SSH access to your Raspberry Pi. Simply create an empty file named ssh in the "boot" volume.

   6. Now, unmount the volume and insert the MicroSD card into the Raspberry Pi, then turn it on.

      Once it powers up completely, you will need to connect to it via SSH. Issue the command ssh pi@raspberrypi. The default password is raspberry
      Depending on your router's DHCP and DNS settings, the hostname may not resolve. In that case, you will have to look at your router settings to see the list of connected devices, then connect to your Raspberry Pi via the IP address assigned by your router.

      Optionally, if you generated an SSH key to connect to the school's servers in the previous studio, you may want to use the same key to connect to your Raspberry Pi. The installation steps outlined after generating the key in our SSH key instructions should help you to do so.

   7. As a last step, you will need to configure your Raspberry Pi so that you can interract with its desktop environment from your laptop or desktop. You will need to enable VNC on the Raspberry Pi, then install a VNC viewer on your computer.

      Issue the following command to your Raspberry Pi via the SSH connection: sudo raspi-config

      You will see a menu with several options. You will use the Raspberry Pi's desktop environment to set several of these options. For now, select 3 Interface Options, then P3 VNC, then select Yes to enable the VNC server. Select Finish to exit the configuration menu.

      Now, you will be able to connect to your Raspberry Pi's desktop environment by using a VNC viewer. We recommend the RealVNC Viewer, which is free and has versions for several operating systems, including Windows, MacOS, and Linux. Depending on your system, you may need to run the installation package as an administrator or root user. If not, the installer may not progress past 0%.

      Once you have downloaded and installed the VNC Viewer, enter the hostname or IP address for the Raspberry Pi into the search bar, then press enter. You will be prompted for a username and password to connect to the Raspberry Pi. This is the same username and password used for SSH, which are pi and raspberry by default.

      Note that if you run into problems later (e.g., when trying the optional enrichment exercise) and are completely shut out of your Raspberry Pi, you can re-image it by shutting it down, removing the MicroSD card, then repeating the prior steps. This will destroy the image that was already there, but gives you a way to recover to this initial starting point.

   This in turn is strong motivation to back up copies of your work on other machines (possibly using svn, git, or another repository service, use multiple Raspberry Pi machines within your group for redundancy, etc. Starting with the next week's exercises, we will be making substantial changes to code etc. that you will need to manage effectively even if your Raspberry Pi should freeze up, lock you out, etc.

   Once you have successfully installed and booted the Raspberry Pi OS, and can see the desktop, please tell us briefly about your setup as the answer to this exercise. For example, are you using Washington University's WiFi network, or your home WiFi? Do you have a monitor, keyboard, and mouse connected, or did you perform a headless setup? If headless, are you connecting with SSH, RealVNC, or through another method? And, if headless, what operating system are you using on the computer that connects to the Raspberry Pi?

5. Now, you are ready to configure location and user settings for your Raspberry Pi.

   When your Raspberry Pi first logs in, you will see a setup wizard titled "Welcome to the Raspberry Pi." Click Next.

   On the Set Country screen, use the following options:

   • Country: United States
   • Language: American English
   • Timezone: select a timezone as appropriate to your location (e.g. in St. Louis, you will use Chicago).
   • Check: Use English language
   • Check: Use US keyboard
   • Click Next

   In its default configuration, the Raspberry Pi is usually set up to boot automatically into a default account with username pi and password raspberry, which is not very secure for long-term use. To help avoid having your Raspberry Pi recruited into an evil bot swarm (or other undesirable and unauthorized use), the setup wizard now prompts you to enter a new password. Type in (and re-enter to confirm) a suitably strong new password that you should please also record somewhere so you can still get access to your Raspberry Pi.

   As the answer to this exercise please say yes or no for each of the following 5 items, to indicate whether your new password (1) contains at least one lowercase alphabetic character, (2) contains at least one uppercase character, (3) contains at least one numerical character, (4) contains at least one non-numeric, non-alphabetic character, and (5) is at least 8 characters long (if the answer to each of these is yes, then your password may be strong enough to be accepted - if not, keep trying until you succeed).

6. On the next screen, please indicate if your screen shows a black border around the desktop. You should not need to check this box if you are running a headless Raspberry Pi and connected via VNC.

   The next screen will prompt you to connect to a WiFi network.

   If your Raspberry Pi is already connected to a network (e.g. because you are using a wired Ethernet Connection, or have followed the procedure for a headless Raspberry Pi), you may Skip this step.

   You should also Skip this step if you plan to connect your Raspberry Pi to Washington University's WiFi network. Connection details are given in a later step.

   Select an appropriate WiFi network, then enter the password to connect.

   The Raspberry Pi will now prompt you to Update Software. Click Next, which will allow the Raspberry Pi to automatically download and install the necessary updates.

   Finally, the setup wizard will indicate that your Raspberry Pi is now set up and ready to go. Do not restart it yet; there are a few more steps to complete.

   Click on the raspberry icon at the top left of your desktop, select the Preferences menu item and then from that menu select the Raspberry Pi Configuration menu item.

   If you are not using your own router, you may want to change your hostname from the default raspberrypi to something unique so that it does not conflict with others in the course. For example, choose a hostname that contains your username.

   If you are connected with VNC, you may notice that the screen resolution is extremely small. Click the Display tab, then click Set Resolution. Select a resolution as appropriate for your monitor, then click OK (or simply close the window with the "x" in the top corner of the menu, if the resolution is so low that the OK button is off the screen).

   Click OK to apply the settings and exit the Configuration menu. If your screen resolution is too small to see the OK button, you can close the settings window. Reboot your Raspberry Pi.

   If you are connecting to your Raspberry Pi with VNC, note that it will not reconnect automatically, because you have changed your password (and possibly your hostnmae). You will need to reconnect with the new password, and if you changed the hostname, you may need to set up a new connection to the Raspberry Pi.

   As the answer to this exercise, please tell us the hostname assigned to your Raspberry Pi.

7. We will now look at network settings on your Raspberry Pi.

   First, open up a terminal window on your Raspberry Pi, and in it enter the command
   
   ifconfig wlan0
   
   and note the MAC address that appears after the word ether. The MAC address should consist of six hexadecimal numbers separated by colons, like 00:00:00:00:00:00 (but with values from 0 to 9 and a through f for the digits).

   We will now set up wireless networking so that you can access the internet from your Raspberry Pi on Washington University's WiFi network.

   In a browser on a windows machine in the lab, visit the university's https://selfservices.ip.wustl.edu web page, and underneath the User Registration heading please fill in the fields with your Pi's MAC address, your WUSTL Key id and password, and your first and last name. Then, click on the register button at the bottom of that page and wait until it updates with a message saying that the registration was successful.

   Then, on your Raspberry Pi, please click on the wireless networking icon to the upper right on its desktop, and select the wustl-2.0 network from the list that should appear (possily after a brief wait). If prompted to do so, enter your WUSTL Key id and password, and once you are connected to the network, click on the browser icon that's next to the raspberry icon on the top left of your desktop, to open up a browser. Enter the URL of the home page for this course, https://www.cse.wustl.edu/~cdgill/courses/cse522/ and confirm the page loads.

   Once you have done that, in the terminal window on your Pi enter the command
   
   hostname -I
   
   and note the IP address that appears.

   As the answer to this exercise, give both the MAC address and the IP address for your Raspberry Pi.

8. Finally, we need to transfer our recently compiled kernel and modules that we built in the previous studio to our Raspberry Pi in order to install them.

   To make the transfer process faster, you will first need to compress the files that you will be retrieving.

   Use ssh to connect to shell.cec.wustl.edu. Then, navigate to the directory where you compiled the Linux kernel with:

   cd /project/scratch01/compile/"your username"/linux_source

   Next, create two archives with the following commands:

   tar -C modules/lib -czf modules.tgz modules

   tar -C linux/arch/arm -czf boot.tgz boot

   Now, open a local terminal on your Pi.

   Alternatively, in this and all future assignments, you may use SSH to run terminal commands on your your Raspberry Pi.

   Create a directory called linux_source that will serve as a place to organize your code. (Note: this does not need to be created under /project/scratch01/compile, as only you will be running a kernel on your Pi.) Move inside your linux_source directory and run the following commands:

   sftp [your wustl key]@shell.cec.wustl.edu

   cd /project/scratch01/compile/"your username"

   cd linux_source

   get modules.tgz

   get boot.tgz

   quit (to get back to your Pi)

   Back up your directories /usr/lib/modules and /boot, because you will be modifiying their contents. To do this, we used sudo cp -r /usr/lib/modules ~/Desktop/modules_backup and a similar command for /boot.
   
   Note that on some versions of Linux, /lib may be a directory rather than a symbolic link to /usr/lib. In that case, please use
   
   sudo cp -r /lib/modules ~/Desktop/lib_backup
   
   to back up that directory instead.
   
   You should still be in your linux_source directory (if not, navigate there).

   Once you have backed up the /usr/lib/modules and /boot directories, run the following commands to install the kernel you built:

   tar -xzf modules.tgz

   tar -xzf boot.tgz

   cd modules

   sudo cp -rd * /usr/lib/modules (or sudo cp -rd * /lib/modules if /usr/lib does not exist)

   cd ..

   sudo cp boot/dts/*.dtb /boot/

   sudo cp boot/dts/overlays/*.dtb* /boot/overlays

   sudo cp boot/dts/overlays/README /boot/overlays

   Finally, if you are using a Raspberry Pi 3B+, run the command:
   
   sudo cp boot/zImage /boot/kernel7.img
   
   If you are using a Raspberry Pi 4 or 4B, run the command:
   
   sudo cp boot/zImage /boot/kernel7l.img

   At this point, your new kernel is installed. When you reboot, you'll be running your very own, custom kernel.

   Go ahead and reboot now. If everything went OK, the new system should look and feel the same as before. You can verify that your new kernel is running with the command uname -a. In particular, the build date should be today, the version string should include the local version string you specifed during configuration, and your Linux source code version (as well as the characters "PREEMPT") should appear.

   As the answer to this exercise, give the output that was just produced by running uname -a for the new kernel.

9. Things to Turn In:

   For this studio, please turn in the following:

   • A file with your answers to the required exercises (and to the enrichment exercise if you did it)

   ---

   Optional Enrichment Exercise

10. Please see the Linux Users - Raspberry Pi Documentation page for more information about how to add other user accounts to your Raspberry Pi, create home folders, etc.

    Be careful with some of the commands on that page, as they can remove accounts, remove passwords, etc. which can leave you without a way to get into your Raspberry Pi (forcing you to start all over by re-imaging your MicroSD card, etc.)

    As the answer to this exercise, describe what you did and what you saw when you did that.

Page updated Monday November 29, 2021, by Marion Sudvarg, James Orr, and Chris Gill.