How to connect to wifi raspberry pi headless? - ssh

Question

I know there are a bunch of blogs explaining how to set up the wifi headless on the raspberry pi. I have followed them and they worked, once. But I had to format the sd card, and re-do it and it doesn't connect to the WiFi anymore.
I use the RPI Imager to write the OS. (Note I've also tried with the advanced option pressing Ctrl + Shift + 10, and set up the wifi, ssh over like this. After writing it, the verification returned an error that couldn't create a FAT32 partition).
Then I created a blank ssh file inside the sd card (boot) to allow the ssh connection.
Then I created the wpa_supplicant.conf file containing this:
country=CZ
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
ssid="NETWORK-NAME"
psk="NETWORK-PASSWORD"
}
Then I eject the sd card, insert it in the raspberry pi and it doesn't connect to the wifi.
I know that the Raspberry pi, and the wifi connector work well. So it must be something that I'm misssing.
I'm honestly desperate at this point since I have spent more than 10 hours just trying to connect to the WiFi. I have formated and re-installed the Raspberri-OS a bunch of times already, and tried as many tutorials as I could find.

Answer 1

There's not really a single universal answer to your question, so at the risk of telling you a bunch of things you already tried, here's my exhaustive list of stuff to try/consider:
If you're using Ubuntu you probably have to use netplan - see here for some instructions https://askubuntu.com/questions/1143287/how-to-setup-of-raspberry-pi-3-onboard-wifi-for-ubuntu-server-with-netplan
Don't forget your key_mgmt field (use the value relevant to your wifi):
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=CA
network={
ssid="NETWORK_SSID"
psk="PSWD"
key_mgmt=WPA-PSK
}
If you can ssh into with a wired connection, and are using Raspian, you may find using raspi-config easier (sudo raspi-config, then System Options > S1 Wireless LAN).
Now we get into the "I already checked that five times" part of the list:
a)if you're using Ubuntu/netplan, ensure you're using the correct interface id by doing ifconfig - should be wlan0, but you never know
b)ensure you have your SSID correct - you can do sudo iw wlan0 scan to find all the networks in reach and double check the SSID. Watch out for weird quotation marks (e.g. 'smart' quotes), elongated dashes and stray spaces - in particular if you have pasted the SSID and password from elsewhere
c) ensure your SSID, password and key setting is correct by checking a different device
d) ensure you are looking for the right IP address on your LAN - you can do a sudo nmap -sn 192.168.1.0/24 and your Pi devices should show up looking like:
Nmap scan report for 192.168.1.68
Host is up (0.00044s latency).
MAC Address: B8:27:EB:8B:73:AD (Raspberry Pi Foundation)
Remember that if using DHCP, your Wifi and Wired connections will get different IP addresses - if using static for Wired, you'll also likely get a DHCP address for your wireless interface.
If you keep failing using the same Raspian image, try something different, just to isolate the problem - e.g. try Ubuntu if you keep failing with Buster (or vice versa)
Finally, some more general advice about what to do when you're just so frustrated with a problem that you've spent way too much time on - write out a 'proof' of why what you're trying to do is impossible, explaining line by line how you've done exactly the steps that are supposed to work. This is my method of last resort, and currently has a 100% success rate - when I try to explain why the thing is impossible, I realize what I didn't do, overlooked, or did wrong.

Answer 2

Actually, I solved this by following this blog https://weworkweplay.com/play/automatically-connect-a-raspberry-pi-to-a-wifi-network/?fbclid=IwAR2QckXB5XMPLCttnyBDUWv-MgxFsk0utfih4FHpF1za4OzH-9h-SKgR0GM and adding some stuff to the /etc/network/interfaces/