🛠 Se connecter au Wi-Fi en ligne de commande (nmcli)

Objectives

Diagnose and configure the Wi-Fi on the Zero W from a terminal: the board features the Cypress CYW43438 chip (802.11n 2.4 GHz only, ~35 Mb/s, + Bluetooth 4.0/BLE), interface wlan0.

Hardware

• 1 Raspberry Pi Zero W running Raspberry Pi OS (SSH session or screen + keyboard via mini-HDMI / micro-USB adapters)
• A 2.4 GHz access point

Steps

1. Set the radio country: sudo raspi-config → 5 Localisation → L4 WLAN Country. Incorrect country = incorrect channels/power, legality issues, and degraded performance.
2. Check the radio: nmcli radio wifi must display enabled.
3. Scan: nmcli dev wifi list (SSID, SIGNAL, SECURITY).
4. Connect: sudo nmcli --ask dev wifi connect <ssid_of_the_spot> then enter the passphrase.
5. Check the link and signal level: iw dev wlan0 link (signal: line in dBm).

nmcli -t -f IP4.ADDRESS dev show wlan0   # bail DHCP
ping -c 3 1.1.1.1                        # sortie Internet

Verification

iw dev wlan0 link displays SSID, channel, and signal; ping goes out to the Internet.

Common Errors

• Looking for 5 GHz: the Zero W is single-band 2.4 GHz, with the same chip as the Pi 3 B.
• Metal case: the antenna is a simple PCB trace (cut ground plane); metal significantly weakens it.
• WLAN country not set: network "not found" even though it is broadcasting on a channel outside the allowed domain.