Did this for a roof inspection drone, so here’s what I ended up with.

On the Pi, pymavlink reads the MAVLink stream from TELEM2. You only need two messages: GLOBAL_POSITION_INT (lat/lon in 1e7 degrees, relative altitude in mm) and SYS_STATUS (battery voltage in mV). Once a second, publish a flat object over MQTT with TLS:

from pymavlink import mavutil
m = mavutil.mavlink_connection("/dev/serial0", baud=921600)
state = {}
while True:
    msg = m.recv_match(type=["GLOBAL_POSITION_INT", "SYS_STATUS"], blocking=True)
    if msg.get_type() == "GLOBAL_POSITION_INT":
        state.update(lat=msg.lat / 1e7, lng=msg.lon / 1e7, alt_m=msg.relative_alt / 1000)
    else:
        state["batt_v"] = msg.voltage_battery / 1000
    if time.time() - last >= 1:
        client.publish("v1/telemetry", json.dumps(state), qos=1); last = time.time()

Name the keys lat and lng, that’s what the Map card looks for by default.

On the board, a Map card. Bind Points to the drone’s latest values (lat, lng), and that’s your live marker. Bind Routes to Device readings over time with the keys lat,lng, and turn on Replay controls. The client can play the flight back at 1x to 10x and scrub. Add a value card for battery and altitude next to it. Satellite map style helps them see the panel rows.

1 message a second is far inside the default per-device limits. And keep it read-only: no commands from the board to the drone, the pilot flies it.

No VPN at those sites I’d bet, that’s the point of the panel feature.

Router A: you can’t switch that from Hermetry, by design. “Allow panel access from my cloud account” is the router owner’s local consent and lives only on the router’s own Cloud page. Someone on site has to turn it on once. We had a farmer do it with me on the phone, it took five minutes: log into the router’s local panel from a laptop on the LAN, Cloud page, tick the switch. After that Open panel works from anywhere.

Router B: the firmware is too old for panel sessions. Update it through Hermetry’s firmware page. For a router that far away I’d do it on its own first, not as part of a wave, and check its Firmware tab for the Updates over LTE setting if it’s on the mobile uplink. Licensed devices have local approval and metered-link rules, so it may sit in Waiting until those allow it.

Couple of things for when it works. If the router is on LTE you get a confirm that the session may use up to 50 MB and is then closed. Sessions end after 30 minutes without use or 4 hours total. Only the person who opened a session can enter it, so a colleague opens their own. And what you change inside the panel is up to you, opening it changes nothing.

All the refusal messages are listed on Remote access to a router’s panel.