Raspberry Pi Basics

A small crash course on setting up and using the Raspberry Pi (as a server, ftp storage, home-base, etc.)

What is a Raspberry Pi?

A Raspberry Pi is a credit card sized computer that can run Linux (and other OS) to do almost anything your computer can do. It can be simply connected to a monitor/TV, keyboard and mouse and be used as a regular computer. Because of its low power consumption, it is used as a web-server, file storage system, home automation system, etc. It can also be connected to an Arduino to aid in robotics such as the PiCar.

Setting up a Raspberry Pi with SSH

Materials Required

  • Raspberry Pi 3 B+ (older models will also work)
  • Pi compatible power adapter
  • Micro SD Card (with alteast 16GB of memory; you may need an SD card adapter to connect it to your computer)
  • USB keyboard and mouse
  • Access to a monitor + HDMI cable
  • Access to your router, or a new router
  • A laptop for remote access to the Pi

Procedure

Note

If you are a Washington University student working on the PiCar project, you can skip to step 10 and use the given IP address of the Pi to communicate with the Pi. However it is recommended to atleast glance through the steps to see what was done.

  1. Download the Raspbian Stretch with Desktop image.

  2. Download Etcher

  3. Install Raspbian OS to the Raspberry Pi:

    • Insert SD card into your computer.

    • Run Etcher.

    • In Etcher, choose the downloaded Raspbian zip or image file.

    • Choose the SD Card drive

      Warning

      Ensure to select the correct drive (SD Card) because it will be formatted.

    • Flash the Raspbian image.

    • Eject SD card and put it into the Raspberry Pi.

  4. Connect the mouse, keyboard and monitor to the Raspberry Pi. Finally connect the power cable to turn on the Raspberry Pi.

  5. The default login credentials for the Raspberry Pi are:

    • username: pi
    • password: raspberry

  6. Change the password to your liking by opening the terminal and typing:

    sudo passwd pi

  7. Use the following command to enable SSH (Secure Shell) which will be used to communicate to your computer wirelessly.

    sudo raspi-config
    • Navigate to Interfacing Options >> SSH >> Enable

  8. Connect the Pi to your router (which is connected to your company/university internet port) and reboot the Pi using:

    sudo reboot now

  9. Get the local IP address of your Pi using:

    hostname -I
    • You will find your Pi’s local IP (eg: 192.168.1.123)
    • Alternatively you can navigate to the router admin page to check the IP addresses of connected devices.

  10. On your laptop, connect to the router and use the following instructions based on your OS:

    Windows:
    • Download Putty
    • Run Putty
    • For the hostname, use the IP address you got for the Pi (eg: pi@192.168.123), and click Open
    Mac/Linux:
    • Open terminal and type (using the Pi’s IP address):
    ssh pi@192.168.1.123

  11. Doing so will prompt you to enter the Pi’s new password. Enter it.

Note

The default port used by Pi for SSH is 22. As long as your router and Pi password are strong, the security risk is minimized. Currently, SSH will only allow you to access the Pi when your computer and the Pi are connected to the same router.

Note

The IP addresses of devices including the Raspberry Pi may change each time you reboot it. To solve this you could either set up a static IP address for each Pi or create a way to email the IP to your email address.

Desktop Interface

Sometimes an terminal only interface does not suffice. We can alternatively connect to the Raspberry Pi using a VNC (Virtual Network Computing) Viewer to see the ‘screen’ of the Pi.

Procedure

  1. Login to the Pi as usual using SSH

  2. Enable VNC by using the following command:

    sudo raspi-config
    • Navigate to Interfacing Options >> VNC >> Enable

  3. Reboot the Pi

    sudo reboot now

  4. Install VNC Viewer on your laptop.

  5. Open VNC viewer. Open a new connection: File >> New Connection

    • Use the local IP of the Pi and the SSH port (22 by default)
    • Use your credentials to login

  6. You should be able to see the same screen that you saw when you initially connected to the Pi using HDMI

Note

For SSH connection to work, your laptop needs to be connected to the same WiFi (router) that the Raspberry Pi is connected to.

Password-less SSH

For SHH via a private computer, you can use an SSH key pair to login to the server or Raspberry Pi without a password

Procedure

  1. Open a new terminal window and type the following command to generate a SSH key pair. You will keep the private key on your computer and send the public key to the server which will authenticate SSH connection without the password.

    ssh-keygen -t rsa

* Follow through the process. If key pair has been generated previously,
choose a new file name. A passphrase is not necessary.

  2. The following commands will create a SSH directory on the Pi, upload the generated public key to to the Pi and set the necessary permissions (replace <Pi IP Address>, <Pi SSH Port (defaut: 22)> and <Pi username> with their respective names/numbers):

    ssh_ip=<Pi IP Address>
ssh_port=<Pi SSH Port (defaut: 22)>
ssh_user=<Pi username>

ssh $ssh_user@$ssh_ip -p $ssh_port mkdir -p .ssh
cat ~/.ssh/id_rsa.pub | ssh $ssh_user@$ssh_ip -p $ssh_port 'cat >> .ssh/authorized_keys'
ssh $ssh_user@$ssh_ip -p $ssh_port "chmod 700 .ssh; chmod 640 .ssh/authorized_keys"

    Note

    You will need to enter the SSH password for the above steps. Also, there is no space between ssh_pi, = and <Pi IP Address>, etc.

  3. Now the SSH keys have been set up. To make the connecting via SSH even faster, do the following:

    cat ~/.ssh/config
    • If the ~/.ssh/config file does not exist, create one using nano:
    sudo nano ~/.ssh/config
    • Fill it in the following format:
    Host <some unique name>
   Hostname <Pi IP Address>
   User <Pi username>
   Port <Pi SSH Port (defaut: 22)>
    • Or you can use the following command:
    ssh_id=<some unique name>
echo "Host $ssh_id" >> ~/.ssh/config
echo "  Hostname $ssh_ip" >> ~/.ssh/config
echo "  User $ssh_user" >> ~/.ssh/config
echo "  Port $ssh_port" >> ~/.ssh/config
    • Example (in ~/.ssh/config):
    Host pi-server
   Hostname 192.168.1.200
   User pi
   Port 22
    • Save the file

  4. Now you can SSH in to the Pi without a password using the command:

    ssh pi-server # or whatever host identifier you chose