WiFi Access Point Setup (Pi 1)¶

Pi 1 acts as the command Pi and hosts a WiFi access point that the Flutter app connects to. The onboard wlan0 is used for the BATMAN-adv mesh, while a USB WiFi adapter (wlan1) is configured as an access point.

Architecture¶

Flutter app connects to Pi 1 via AP (wlan1 DroneCommandNet 192.168.50.1)

Pi 1 communicates to rest of the drones over BATMAN-adv (wlan0 169.254.97.1)

Prerequisites¶

A USB WiFi adapter that supports AP mode plugged into Pi 1 Verify AP mode is supported:

iw phy phy1 info | grep -A 10 "Supported interface modes"

You must see AP in the list.

Setup¶

1. Check NetworkManager is running¶

systemctl status NetworkManager

2. Create the Access Point¶

Current password is multirotor123 (Needs to be over a certain length)

nmcli connection add type wifi ifname wlan1 con-name "DroneAP" autoconnect yes ssid "DroneCommandNet" \
  mode ap \
  ipv4.method shared \
  ipv4.addresses 192.168.50.1/24 \
  wifi-sec.key-mgmt wpa-psk \
  wifi-sec.psk "multirotor123" \
  802-11-wireless.band bg \
  802-11-wireless.channel 6

3. Bring it up¶

nmcli connection up DroneAP

4. Verify¶

iw dev wlan1 info
ip a show wlan1

wlan1 should show type AP and IP 192.168.50.1.

Connecting Devices¶

Devices connecting to DroneCommandNet will receive an IP in the 192.168.50.10-254 range via DHCP (managed automatically by NetworkManager).

To see connected devices:

cat /var/lib/misc/dnsmasq.leases
ip neigh show | grep 192.168.50

Persistence Across Reboots¶

The DroneAP connection is saved by NetworkManager with autoconnect yes so it comes back up automatically after reboot.

The BATMAN startup script (batman-mesh-setup.sh) contains a Pi 1 exception that prevents it from taking over wlan1 for the mesh:

if [ "$PI_NUMBER" = "1" ]; then
    log_message "Pi 1 detected - wlan1 reserved for AP, using wlan0 for mesh"
    UAIN="wlan0"
fi

This ensures wlan1 always stays as the AP on Pi 1 while wlan0 handles the mesh.

Subnet Configuration¶

The AP uses a separate subnet (192.168.50.0/24) from the BATMAN mesh (169.254.97.0/16). This ensures Linux routes traffic correctly:

Verify routing is clean:

ip route show

Should show two separate routes — one via wlan1 and one via bat0.

Troubleshooting¶

DroneAP not showing up after reboot¶

Check if a stale dnsmasq instance is blocking it:

sudo pkill dnsmasq
nmcli connection up DroneAP

Can't connect to the AP¶

Check that hostapd (via NetworkManager) is running:

journalctl -u NetworkManager --since "2 minutes ago" | grep DroneAP

Phone gets wrong subnet IP¶

If the phone gets a 169.254.x.x address instead of 192.168.50.x, the AP subnet may have changed. Verify:

nmcli connection show DroneAP | grep ipv4.addresses

Should show 192.168.50.1/24. If not, fix it:

nmcli connection modify DroneAP ipv4.addresses 192.168.50.1/24
nmcli connection down DroneAP && nmcli connection up DroneAP

Temporarily connecting Pi 1 to internet¶

To get internet access on Pi 1 without losing the AP config:

sudo nmcli connection down DroneAP
sudo nmcli connection add type wifi con-name "temp-wifi" ifname wlan1 ssid "NETWORK_NAME" wifi-sec.key-mgmt wpa-psk wifi-sec.psk "PASSWORD" ipv4.method auto
sudo nmcli connection up temp-wifi

When done, restore the AP:

sudo nmcli connection down temp-wifi
sudo nmcli connection up DroneAP