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SentinelSentinel Documentation

Quick start

This exercise takes one Sentinel from being plugged in to its data being visible in Celestian. You need:

  • An assembled Sentinel with firmware (hardware), with at least one DS18B20 sensor.
  • A PoE switch and a running DC Gateway (gateway guide). Without a gateway, see direct mode.
  • A Celestian account with a workspace and channel for this data.
  • A laptop on the same rack LAN (or one that can reach the Sentinel’s address).

  1. Plug in the PoE Ethernet cable

    Connect the Sentinel to a PoE switch port. The opening screen lasts about 3.5 seconds (the Sentinel eye animation, model name, and firmware version), then the LCD shows the Summary.

    Indicator Meaning
    Green LED, LCD ONLINE Ethernet and MQTT connected
    Yellow LED, NO-MQTT Ethernet is up, broker unreachable
    Red LED, NO-LAN cable or PoE problem, no IP yet
    AUTH! the broker rejected the credentials or client id

    The node takes an IP from the gateway’s DHCP, then uses that gateway IP as broker, NTP server, and OTA server. Nothing needs to be configured.

  2. Note the MAC and address

    On the LCD: press OK, choose Device, the first screen shows the MAC (e.g. a2cb8ff8768d). The Jaringan (Network) menu shows the IP. This MAC is the device Serial in Celestian.

  3. Open the web interface and change the password

    From the laptop, open http://sentinel- followed by the last 6 digits of the MAC and .local (MAC a2cb8ff8768d → http://sentinel-f8768d.local), or use the IP. Log in with user admin, default password sentinel, then change it in the System tab. Details: Web interface.

  4. Name the location and check the sensors

    In the Configuration tab, fill in label (e.g. DC-A/R07, max. 20 characters) and tz_offset_min (WIB 420). The Status tab shows each slot’s temperature; DS18B20 sensors present at boot are automatically bound to slots t1, t2, and so on. Give them meaningful metric names, e.g. t1_name = rack_top.

  5. Register the gateway in Celestian

    In Celestian create a device for the gateway with Gateway mode, save its device key, and connect it to the channel with publish and subscribe types. Enter that ID and key in the gateway (Bridge to Celestian).

  6. Register the Sentinel and add a storage rule

    The Sentinel appears automatically in the gateway’s Roster tab (recognized by MAC). Register it as a device with Serial = MAC. Make sure the channel has a storage rule, otherwise messages are received but not stored. Details in Using Sentinel in Celestian.

  7. See the data

    Open the device detail in Celestian: metrics rack_top, voltage, alarm_level and others start filling every 10 seconds. From a laptop on the rack LAN you can also watch directly:

    Terminal window
    python3 Tools/celestianctl.py --host 10.10.0.1 watch

    Example incoming telemetry (SenFlat v2, slightly tidied):

    {"f":"flat","v":2,"q":4821,"h":0,"s":[{"id":"a2cb8ff8768d","t0":1790000000000,"ts":1,"m":{"rack_top":22.44,"voltage":230.1,"power_draw":948,"alarm_level":0}}]}

Next steps

Section titled “Next steps”