prep.md

Prep your Pi

To prepare your Pi, you will need:

• Raspberry Pi 4
• Power Supply
• SD card + Reader
• Adafruit MiniPiTFT

Burn your Pi image to your SD card

On your computer

• Download the Raspberry Pi Imager

• Download our copy of Raspbian at this Cornell Box link. Download and use the pi_image_09-05-23.zip file directly in the Raspberry Pi Imager (do not unzip).

• If using windows: Windows 11 SSH Client, PuTTY or VS Code SSH.

Setting up your OS for the Pi

1. Plug the SD card into your computer using the card reader

2. Go download and install the Raspberry Pi Imager on your laptop, download the the customed image file we made for the class. Open the Raspberry Pi Imager and choose the downloaded image file from "Choose OS" and the SD card from "Choose SD card".

3. Click the gear icon on the bottom right to open Advanced Settings. In here, you need to make two changes:

• change the "hostname" to something unique
• set the password for user "pi" to something unique to you that you can remember
• do not change any of the other settings (username pi and network should stay as they are)

4. Eject or unmount the microSD card reader, and then remove the SD card from the reader and reinsert it into SD card slot on the Pi: it is located on the bottom (silver rectangle on the right).

5. Take and connect the Adafruit MiniPiTFT to your pi with the configuration shown below, the MiniPiTFT should be on the top left corner of your Pi.

6. Boot the Pi by connecting it to a power source with USB-C connector.

Setting up your Pi to run in headless mode

Connecting to your Pi remotely

Unlike your laptop, the Pi doesn't come with its own keyboard or mouse. While you could plug in a monitor, keyboard, and mouse we will be connecting to your Pi over SSH. You can do this in Mac Terminal or Windows 10 SSH Client.

Note: This set up assumes you boot your raspberry pi the first time when on campus or in The House. If you have a screen, mouse and keyboard you can edit the /etc/wpa_supplicant/wpa_supplicant.conf on the pi to make it connect to your home network already now.

1. When you boot up your Pi, the MiniPiTFT should have the following information shown:

   IP: xxx.xxx.xxx.xxx
   NET: [YourWifiNetwork]
   MAC: xx:xx:xx:xx:xx:xx
   

   The IP address is what you will need to SSH your Pi later through the same network. The media access control address (MAC address) is a unique identifier assigned to a network interface controller, you will need it later for registering the device if you are using Cornell network (e.g. RedRover). The NET shows which WiFi network your Pi is connected to.

   For MAC address: If you are planning to use Cornell network (e.g. RedRover and eduroam), you will have to register the device (your Pi) to the Cornell System to get it online. Please follow the instructions here from Cornell. To get the wifi mac address type cat /sys/class/net/wlan0/address in the terminal once looged in to you pi and verify its the same shown on the Pis screen. If you are using the House network, you will need to register the device (your Pi) through whitesky. You might need to wait for a few minutes for your Pi to actually get online after registering it.

   Note: Next to the screen are two buttons. We configured the top left button on this screen to shutdown your Pi. Do this before you disconnect the power source. The bottom left button is configured to reboot the Pi.

2. Verify your Pi is online. In the terminal of your laptop, type ping <Your Pi's IP Address shown on the MiniPiTFT> and press enter. If your Pi is online, you should get similar messages as below (with different IP address):

   $ ping 192.168.1.131
   PING 192.168.1.131 (192.168.1.131): 56 data bytes
   64 bytes from 192.168.1.131: icmp_seq=0 ttl=64 time=252.118 ms
   64 bytes from 192.168.1.131: icmp_seq=1 ttl=64 time=10.331 ms
   64 bytes from 192.168.1.131: icmp_seq=2 ttl=64 time=10.209 ms
   64 bytes from 192.168.1.131: icmp_seq=3 ttl=64 time=14.816 ms
   ^C
   --- 192.168.1.131 ping statistics ---
   4 packets transmitted, 4 packets received, 0.0% packet loss
   round-trip min/avg/max/stddev = 10.209/71.868/252.118/104.084 ms

   You can use control-C to interrupt and exit the ping (press the control key, and while holding it down, also press the C key, then let go of both together--this looks like ^C in the terminal).

3. Once your Pi is online, you can go ahead and SSH into the Pi. In the terminal of your laptop, type in the command

   $ ssh pi@<Your Pi's IP Address shown on the MiniPiTFT>
   

   When you first log in it, the terminal will show you a "fingerprint" and ask you whether you want to continue connecting. Type yes and press enter.

   ```shell
   $ ssh pi@192.168.1.131
   The authenticity of host '192.168.1.131' can't be established.
   ECDSA key fingerprint is SHA256:Y9S4oMH2H70fz3K/L42Kw39k+zkpyfr0DmGdzBx7SKk.
   Are you sure you want to continue connecting (yes/no)? yes
   ```
   After you authorize the SSH, you should get the following message asking you to provide the Pi's password.
   ```
   Warning: Permanently added '10.58.130.183' (ECDSA) to the list of known hosts.
   pi@192.168.1.131's password:
   ```
   

   If you set your password in the Advanced Settings during imaging, enter that password. If you didn't, the initial setting of your Pi's password is raspberry, type it and press enter. Note: the terminal will not show what you type for security so do not worry about it and just make sure you type the correct password. After that, you should see something similar to this:

   ```shell
   pi@192.168.1.131's password:
   Linux ixe00 4.9.59-v7+ #1047 SMP Sun Oct 29 12:19:23 GMT 2017 armv7l
   
   The programs included with the Debian GNU/Linux system are free software;
   the exact distribution terms for each program are described in the
   individual files in /usr/share/doc/*/copyright.
   
   Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
   permitted by applicable law.
   Last login: Wed Jan 17 10:42:03 2018
   
   SSH is enabled and the default password for the 'pi' user has not been changed.
   This is a security risk - please log
   
   in as the 'pi' user and type 'passwd' to set a new password.
   
   pi@ixe00:~ $ 
   ```
   

   This means you are signed in and your terminal is now connected directly to the 'terminal' on your Pi, via ssh. You can tell this by looking at the user and hostname at the beginning of each line, which should now look like:

   pi@ixe00 ~ $

If you didn't already set your password, change the password of your Pi

Because the Pi asked you to! Also to keep your Pi from getting hacked. Write it down somewhere because we do not know how to recover lost passwords on the Pi. In the terminal on your Pi, type sudo raspi-config and press enter, you should be able to see the manual of your Pi:

Choose '1. System Options' and 'S3 Password', they terminal will then ask you to enter your new password. Again, the terminal will not show what you type for security so do not worry about it and just make sure you type the correct new password twice. After you change the password successfully, you will have to use the new password next time you SSH to your Pi.

(Optional) Add additional WiFi networks

This is for if you are not living in The House and want to connect to a WiFi network that isn't Red Rover or The House. In the terminal on your Pi, type in $ nano /etc/wpa_supplicant/wpa_supplicant.conf

You should see a list of WiFi login details in this file:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=US

network={
        ssid="RedRover"
        key_mgmt=NONE
}

network={
        ssid="The House"
        key_mgmt=NONE
}

Under "The House" and "RedRover", add your home WiFi name and password to the bottom of the file.

If the pi and you are at a new location without external screen and mouse you can also create a new E:\wpa_supplicant.conf file with your desktop computer directly on the SD card root which will overwrite the network configuration.

Refresh your knowledge of command line interfaces:

The command line/terminal is a powerful way to interact with your computer without using a Graphical User Interface (GUI). When you SSH onto your Pi, you have a prompt you can enter commands. In your terminal there is a shell, there are many shells but for this class we will use one of the most common bash

````
pi@ixe00:~ $ echo $SHELL
/bin/bash
````

In the code above we've typed echo $SHELL. The echo tells it to print something to the screen. You could try typing echo 'hello' to see how that works for strings. The $ at the front of $SHELL tells bash we are referring to a variable. In this case it is a variable the OS is using to store the shell program. In a folder /bin is a program called bash that we are currently using. The up arrow with show the most recent command.

Navigation in the command line

There are many commands you can use in the command line, they can take a variety of options that change how they are used. You can look these up online to learn more. Many commands have a manual page with documentation that you can see directly in the terminal by typing man [command]. For example:

```shell
pi@ixe00:~ $ man echo
ECHO(1)                           User Commands                          ECHO(1)

NAME
       echo - display a line of text
SYNOPSIS
       echo [SHORT-OPTION]... [STRING]...
       echo LONG-OPTION
DESCRIPTION
       Echo the STRING(s) to standard output.
       -n     do not output the trailing newline
       -e     enable interpretation of backslash escapes
       -E     disable interpretation of backslash escapes (default)
       --help display this help and exit
       --version
Manual page echo(1) line 1 (press h for help or q to quit)
```	

These are some useful commands. Read the manual pages for advanced usage.

• pwd - print working directory, tells us where on the computer we are
• ls - list the things in the current directory.
• cd - change directory. This lets you move to another folder on your machine.
• mkdir - make directory. You can create directories with this command
• cp - copy a file. You can copy from one place to any other place
• mv - move a file, also used to rename a file
• rm - delete a file. To delete a folder you need the recursive flag rm -r [folder]
• cat - view a file
• nano - this is a text editor (there are many) that will let you edit files in terminal.

There is plenty more to learn about using the terminal to navigate a computer but this should give a good start for getting around the raspberry pi.

Using VNC to see your Pi desktop

Another convenient way to remotely connect to your Pi is using VNC (Virtual Network Computing), it essentially is remote login. The easiest client to use is VNC Connect. Download and install it. Once that's done type the IP address of your Pi in the text-box at the top.

After that a login window should appear, use your normal logins (originally: Account=pi, Password=raspberry).

You might want to change a few settings to improve the VNC experience such as changing the display resolution. To change the resolution, run the command sudo raspi-config, navigate to Display Options > VNC Resolution, and choose an option. See here for more troubleshooting realvnc.com Pi Setup.

At that point the normal RPi desktop should appear and you can start and stop programs from here.