Install RPi OS Lite - for headless mode - on SD card

About

This shows step-by-step details onf how to install the latest (as of Feb 2022) Raspberry Pi Operating System (OS) provided by the Raspberry Pi Foundation - to create a Raspberry Pi in Headless mode. I use a macbook. If you have a PC, the steps are similar (using the Raspberry Pi Imager is simplest). I use terminal and linux commands on both mac and Raspberry Pi to set-up.

These are very detailed instructions written for somebody who has never seen Raspberry Pi before, and who has never used the terminal on the Mac, nor any Linux commands. As a result, this post is long. But the actual amount of work is much shorter…

Requirements:

• A computer to download the OS and burn it unto an SD card - I use a MacBook
• A micro SD card - at least 16 GB. I use 32 GB, sometimes 64GB - because I use the RPi to record music - and I need some space…
• An sd card reader if you do not have one integrated in your computer.
• Access to wifi - Please have the wifi SSID and password. The SSID is the name of the router that appears in the list of wifi when you want to connect with your phone or computer. Write down both the SSID and get the password exactly.
• A raspberry Pi: Model 3b+, 4 or pi zero 2 W. Basically you want a 4-core Arm chip + wifi & bluetooth.

the Pi zero W has wifi but only one core. For the Looper, I wrote the software to use multi-core, but the software will work on a single core - the issue is that it may not be able to handle all the work without affecting the live audio: I have not tested it on a single core yet…

On the MacBook - Get ready:

1. On your macbook - open your browser and go to: https://www.raspberrypi.com/software/ and download the Raspberry Pi Imager. Click on “Download for MacOS”.
2. On the mac, navigate to your download folder using finder. Double click on the file imager_xxx.dmg (where xxx is the version number). On my mac - a window opens showing to drag the file unto the application folder like this:

Simply drag the Raspberry unto the shown folder in the window. If you do not get this window, just drag the imager file unto your application folder directly in the finder. Either way - this will install the Imager.

3. Insert the micro SD card, into your card reader (which is connected to your mac).

On the macbook - Select, Download and write the RPI OS to the SD card:

1. Go to your application folder, and launch (double-click) the Raspberry Imager. A window opens:

2. Click on “choose OS”. Scroll down if needed and select(click) option: Raspberry Pi OS (Other)

3. Scroll down the list that appears and select the lite version - either 32 bit or 64 bit as you prefer. If you are not sure stick with 32 bit for now. Click one of these:

   • Raspberry Pi OS lite (32-Bit)
   • Raspberry Pi OS lite (64-Bit)

4. Upon selection, you are back to the imager window. Click on “CHOOSE STORAGE” (under the Storage label). A window appears with the name of the SD card. Click on it to select.

If you have a brand new SD card, you should see something like the name displayed above. If you have a previously used SD card - you might see the name of the card appear. Either way, once selected, all data on the SD card will be erased when you click “write” in the next step.

5. Clicking on the storage option brings you back to the imager window, where the WRITE option is now available (not dimmed as before). Click on “WRITE”, and then click “YES” to confirm that the SD card will be erased (before the RPi OS is copied unto it).

The Imager will download the file for the selected Raspberry Pi OS lite unto the mac, then erase your sd card, write the OS to the card, and perform a verification.

6. You will see a status bar appear: wait for the writing to be complete, and the verification to be complete. (This takes a few minutes).
7. On my Mac - I am asked for the mac password in order to continue: enter your mac password if required.
8. When complete, you will get a message telling you that the operation was complete and you may eject the SD card. Click ” Continue”, then physically remove the SD card from the card reader. You may close the Imager program as well (we are done with it).

ON the Macbook - Prepare the SD Card for RPi headless mode

At this point we will use the terminal - on the macBook - to set a few options on the SD Card, before we transfer it to the Raspberry Pi.

1. Re-insert the SD Card into your mac.
2. To check it: look into finder - it will be listed as “Boot” under “Locations”.
3. Open a terminal window on the macbook.

If you have never opened terminal before - I find the simplest way is to hold the command key down and press the spacebar. This brings up Spotlight - which is a search bar: type “terminal” and hit return. A terminal window will open. It should look like this.

Note the % at the end of the last line in the terminal. This is called the prompt. This is where you enter the commands. Later you will open a terminal window on the Raspberry PI - it will be similar, but the prompt will be a $ sign. It’s a simple way to find out if you are working on the mac in terminal or on the Raspberry Pi: the prompt is different.

4. At the prompt (%) - type the following to navigate to the SD card:

cd /volumes/boot

5. Create an empty ssh file on the SD card - type this command:

touch ssh

6. Create a wpa_supplicant configuration file, which will contain the log in info to your wifi - which will allow your raspberry pi to connect automatically upon first boot. To create the file, open the “nano editor” - which will appear in the terminal - type this command:

nano wpa_supplicant.conf

7. Copy the text below (command-c) and paste it on the first line of editor - in the terminal window:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
ap_scan=1
fast_reauth=1
country=CA
	network={
	ssid="Insert-SSID-here"
	psk="Insert-password-here"
}

8. Using the arrow keys, move to the line: ssid=“Insert-SSID-here”. Erase (using backspace) the words Insert-SSID-here and type in the name of the SSID of your router (which you got in the requirements above). Make sure the double quotes are there. (do not remove them).

you can’t select/highlight words with the mouse in terminal like you do in microsoft word. You have to move around using the arrow keys, and use backspace to erase and type what you want.

9. Again using the arrow keys, go to the password line. Erase the words: Insert-password-here and type in the password for the wifi SSID you selected (be careful - it is case-sensitive). Again make sure you keep the double quotes around the password - do not erase the double-quotes.
10. At this point, your editor should look like this (I show a fake SSID and password as example):

11. Now save the file by typing control-o (hold control key and type letter “o”), and hit return. Then exit the editor by typing control-x.
12. You are back at the prompt (%) in terminal. To verify that the files were created - type the command:

ls

ls is the linux command to list files in the current directory (which is /volumes/boot). You will see a list of files that were placed on the sd card by the Raspberry Pi Imager. Scroll through the list and you should see a file called ssh (no extension) and a file called wpa_supplicant.conf - which are the two files you created.

13. If you want to see the content of the wpa_supplicant.conf file, which you created, type the following command at the prompt:

cat wpa_supplicant.conf

14. At this point, we are ready to transfer the SD card to the Raspberry Pi. Since we are on Mac - we have to eject the card, and to do so we have to ensure that terminal is not longer using it. Type the command:

cd ~

15. This brings back terminal to pointing at your home directory on the mac. The SD card is now free to eject. Go to Finder and click the eject arrow next to the “boot” listing under Locations (should be right under your hard disk):

To the Raspberry Pi

1. Make sure your Raspberry Pi is unplugged (no power - red led is off).

If you have already built the Looper, take the Raspberry Pi out of the Looper case - so you can access the SD Card port.

2. Insert the SD card into the SD card port. (at this point you can place the Raspberry Pi back into its enclosure)

ssh-keygen -R raspberrypi.local

ssh pi@raspberrypi.local

$ sudo apt update
$ sudo apt full-upgrade

cd ~/.ssh
ls

ssh-keygen 

cd ~/.ssh
ssh-copy-id pi@looper64.local

ssh pi@looper64.local