Wi-Fi AP fallback

The Jetson can publish its own Wi-Fi network (HallerRobot, 10.42.0.1/24) instead of joining an existing one. This is the default mode at boot and the reason you can operate a freshly powered Haller in any environment without first finding it on someone's network.

The full Jetson deployment story is on Jetson deployment; this page covers the AP piece in isolation — when you want to debug it, change defaults, or trigger it manually outside the systemd flow.

How it works

Two pieces:

• scripts/setup_ap.sh — a nmcli-driven script that creates an NetworkManager hotspot connection profile and brings it up.
• scripts/haller-ap.service — a systemd oneshot that calls setup_ap.sh start on boot and setup_ap.sh stop on shutdown. Ordered to run before haller-robot.service.

The script uses NetworkManager's ipv4.method shared mode, which gives the AP a DHCP/DNS server out of the box — that's how your laptop gets a 10.42.0.x lease.

Defaults

Change any of these by editing the SSID, PASSWORD, CON_NAME, or WIFI_DEV variables at the top of setup_ap.sh. After editing, sudo systemctl restart haller-ap.service.

Manual start / stop

The script accepts a single arg:

sudo ~/haller_ws/scripts/setup_ap.sh start    # bring up HallerRobot
sudo ~/haller_ws/scripts/setup_ap.sh stop     # tear down + reconnect to last Wi-Fi

stop deletes the hotspot connection profile and triggers an nmcli device connect so the Jetson rejoins whatever Wi-Fi network it last knew. Use this when the Jetson is on your bench and you want to push updates over a real internet connection.

Going through systemd (preferred when the service is installed):

sudo systemctl start  haller-ap.service       # equivalent to setup_ap.sh start
sudo systemctl stop   haller-ap.service       # equivalent to setup_ap.sh stop
sudo systemctl status haller-ap.service       # check current state

Connecting from a laptop

1. Wi-Fi → HallerRobot → password haller2024.
2. The Jetson hands out a lease via DHCP; your laptop gets a 10.42.0.x IP.
3. The HMI is at http://10.42.0.1:3000. SSH is at orin@10.42.0.1.

The Jetson has no upstream Wi-Fi while the AP is active — the dev kit only has one radio. If you need internet access from the Jetson, stop the AP first.

Connecting from a phone

The same HallerRobot SSID works fine for a phone (Android/iOS). The HMI's responsive layout works in mobile browsers, but the dataset-collection and calibration flows assume a keyboard, so an operator phone is most useful for the dashboard's E-STOP + base joystick.

Debugging

• nmcli con show --active — confirms HallerAP is the active connection on the Wi-Fi device.
• journalctl -u haller-ap.service — full systemd log for the service, including the nmcli output from both start and stop.
• iw dev $WIFI_DEV info — kernel-level view of the radio (channel, mode, ssid).
• ip addr show $WIFI_DEV — should show 10.42.0.1/24 once the AP is up.
• Hotspot doesn't appear on laptops/phones. Usually WIFI_DEV is wrong, or the radio is off (rfkill list to check).
• Hotspot appears but the laptop can't get a lease. NetworkManager's ipv4.method shared failed to spawn a DHCP server. Restart the service; check journalctl -u NetworkManager for related errors.

Removing the AP entirely

If you want to permanently switch the Jetson to client-only Wi-Fi:

sudo systemctl disable --now haller-ap.service
sudo rm /etc/systemd/system/haller-ap.service
sudo systemctl daemon-reload
sudo ~/haller_ws/scripts/setup_ap.sh stop    # clears the connection profile too

The haller-robot.service doesn't depend on haller-ap — disabling the AP is safe.

Security notes

haller2024 is a default for getting started. Treat the AP as trust-on-physical-access — anyone in range can connect and reach the HMI on :3000, which exposes E-STOP-able actuators. Before deploying outside a controlled environment:

• Change PASSWORD in setup_ap.sh to something unique.
• Consider putting the HMI behind an auth layer (not currently shipped — see HMI overview for what the surface looks like today).
• If the robot lives on a real network long-term, prefer that to the AP — disable the AP service and let the Jetson join your trusted Wi-Fi.