Architecture

System overview

node (Nano ESP32, BME688, BMV080)
  -> on-device anomaly detector
  -> Blues Notecard (cellular) -> Blues Notehub
  -> Notehub HTTP route -> POST /ingest/notehub   (Wildfire Alarm API)
  -> MariaDB
  -> dashboard (React), incident emails

The API is a Node.js / Express application on MariaDB through the Sequelize ORM. Code is layered: routes/ handle HTTP and validation and stay thin, services/ hold the logic, models/ define the tables.

Notehub ingest

Notehub wraps every note in an envelope with the note file name, the node's JSON body, the Notecard UID, a timestamp and the best known location. The API dispatches on the file name:

File	Sent	Effect
device.qo	once at boot	creates or updates the device
data.qo	every 10 minutes	stores a batch of readings, each tagged with the node's anomaly severity and score
alert.qo	immediately	opens, updates or closes an incident and emails the hosts
anything else	system notes	refreshes the node's last-seen time, location and supply voltage

Idempotency. Notehub retries any delivery that does not get a 2xx answer. Every event carries a UUID: readings are stored under <event>:<index>, and a repeated alert.qo returns duplicate_ignored. A retry therefore never duplicates data or re-sends an email.

Authentication. The Notehub route sends an ingest key created in the dashboard (API Keys, scope "Notehub ingest"). Such a key is accepted only by POST /ingest/notehub and cannot read anything.

Incidents

An incident is one continuous anomaly episode on one node, from the moment the node raises it until it clears. Severities are none, watch, alert, critical and fault. Every raise, update and clear is kept as an incident event, and each one is emailed (plain text, readable on any phone) with the current readings against the node's baseline and a map link. After driving out, the host records the outcome: fire, false_alarm, sensor_fault or unknown.

Live map

GET /map returns everything the dashboard's live map draws:

• every node with its position, last severity and last-seen time;
• for each open incident, the current wind at the node from Open-Meteo and a spread envelope for 30, 60 and 120 minutes;
• NASA FIRMS satellite hotspots from the last 48 hours within 25 km of any node.

The spread envelope is a planning aid, not a fire model. Forward spread is taken as 10% of the 10-m wind speed (Cruz & Alexander 2019), and the shape uses the Canadian FBP length-to-breadth ratio. It ignores terrain and fuel moisture. Weather is cached for 10 minutes, satellite data for 15.

Data model

Model	Description
User	Dashboard accounts, role admin or user
ApiKey	Hashed API keys, scope user (acts as the owner) or ingest (Notehub only)
Device	Sensor nodes, with Notecard UID, location, last severity and voltage
Reading	One value per row: type, unit, timestamp, batch id, anomaly severity and score
Incident	An anomaly episode on one node, with peak severity and outcome
IncidentEvent	Each raise, update or clear, with readings and baseline
Alert, AlertThreshold	Older server-side threshold alerts, kept for compatibility

The schema is applied at startup with sequelize.sync({ alter: true }). There are no migrations yet.

Security model

• Dashboard users sign in and receive a JWT that is valid for 24 hours. Scripts can use a user-scope API key (sk_…) instead.
• Roles come from the database on every request, never from the token or the request body. Registration always creates a user; only an admin can promote someone.
• An admin cannot demote or delete themselves, and the last admin is protected.
• Ingest keys can reach POST /ingest/notehub only.
• Secrets (JWT_SECRET, database passwords, SMTP credentials, FIRMS_MAP_KEY) live in .env, which is never committed.

Rotate your JWT secret

If you suspect JWT_SECRET has leaked, rotate it. Every existing token becomes invalid and users sign in again.