An open-source, collaborative seismic monitoring network built around affordable ESP32-based stations.

Warning

NexaSeis is incomplete and under active development. Expect unfinished features, breaking changes, and limited documentation. Do not rely on it for safety-critical earthquake monitoring or emergency alerts. Of the projects in seismometer/, only NX-1D is currently complete; NX-LSM6DS3 and NX-ADXL355 remain unfinished.

Overview

NexaSeis collects waveform samples from networked seismometers, processes and stores them, and makes live station data available to other applications. This repository contains the complete stack:

• a Python ingestion and processing server;
• a Vue web interface for viewing the network and individual stations;
• firmware and KiCad design files for several ESP32-based seismometers;
• optional WebSocket, DataLink, SeedLink, and REST API services.

The server can be installed as a Python package, while its runtime behavior and station inventory remain controlled by a JSON configuration file.

How it works

ESP32 station ──UDP/TCP──> Python server ──> signal processing ──> SQLite
                                │
                                ├──> REST API / helicorders
                                ├──> WebSocket stream
                                ├──> DataLink
                                └──> SeedLink

Stations send fixed-size binary packets containing a timestamp, station identifiers, and five signed integer samples. The server matches each packet to a station in src/config.json, applies its channel sensitivity and sample rate, buffers the waveform, calculates ground-motion values, and dispatches the result to enabled outputs.

Repository layout

Path	Purpose
src/nexaseis/	Python server, processing pipeline, database, and services
src/config.json	Server, station, and output configuration
nexaseis-web/	Vue 3, Vuetify, and Vite web application
seismometer/NX-1D/	Complete ESP32 firmware for the ADS1256-based one-axis station
seismometer/NX-LSM6DS3/	Unfinished ESP32 firmware and KiCad hardware files for LSM6DS3 stations
seismometer/NX-ADXL355/	Unfinished ESP32/ADXL355 firmware project
fdsnws/stations/	FDSN StationXML metadata
scripts/	Development and integration helper scripts

See the seismometer guide for hardware status, NX-1D setup, and important filter limitations.

For a practical overview of the hardware, read How to build a DIY seismometer.

Requirements

Server

• Python 3.11 or newer
• obspy
• websockets
• simpledali
• simplemseed
• uvicorn
• fastapi[standard]
• numpy

SQLite support is provided by Python's standard library and does not need a separate package.

Web application

• Node.js 20.19+ or 22.12+
• npm

Firmware

• PlatformIO
• an ESP32 development board
• the sensor and electronics appropriate for the selected hardware variant

Server setup

1. Create and activate a virtual environment:

   python3 -m venv .venv
   source .venv/bin/activate

2. Install NexaSeis and its runtime dependencies in editable mode:

   python -m pip install --upgrade pip
   python -m pip install -e .

3. Edit src/config.json. At minimum, change data_path to an absolute directory writable by the server process and configure the station records you intend to receive.

4. Start the server from the repository root:

   ./run.sh

   The installed command and equivalent module command are:

   nexaseis
   python -m nexaseis

By default, a source checkout reads src/config.json. To keep configuration elsewhere, set NEXASEIS_CONFIG to its path before starting the server:

export NEXASEIS_CONFIG=/absolute/path/to/config.json
nexaseis

With the checked-in example configuration, the server listens on:

Service	Default address	Purpose
UDP ingest	0.0.0.0:50006	Receives station packets
REST API	0.0.0.0:50010	Station state and helicorder images
WebSocket	0.0.0.0:50007	Streams processed packets
DataLink	127.0.0.1:16000	Forwards waveform data to a DataLink server
TCP ingest	0.0.0.0:50005	Optional TCP packet input; disabled by default
SeedLink	0.0.0.0:18000	Optional SeedLink service; disabled by default

Binding to 0.0.0.0 exposes a service on every network interface. Use a firewall and more restrictive bind addresses where appropriate.

Station configuration

Each entry in the stations array identifies a station by its network, code, and location. Channels define their own calibration and sampling parameters:

{
  "name": "Example Station",
  "network": "XX",
  "code": "TEST",
  "location": "00",
  "channels": {
    "EHZ": {
      "sensitivity": 5408390926,
      "sample_rate": 100
    }
  },
  "lat": 52.0,
  "lon": 21.0,
  "elevation": 100
}

The network, station, location, and channel values sent by the device must match this configuration. Restart the server after changing the file; configuration is loaded at startup.

API

When the API is enabled, interactive OpenAPI documentation is available at http://localhost:50010/docs.

Useful endpoints include:

• GET / — health and server time;
• GET /stations — latest processed values, grouped by station;
• GET /helicorder/{network}/{code}/{location}/{channel}?type=standard — generated helicorder image. type may be standard, teleseismic, or raw.

Waveform packets are persisted to nexaseis.db beneath the configured data_path.

Web application

Run the development server:

cd nexaseis-web
npm ci
npm run dev

Create a production build:

npm run build

The compiled application is written to nexaseis-web/dist/. Preview it locally with npm run preview.

Firmware

Only seismometer/NX-1D/ is currently considered complete. The NX-LSM6DS3 and NX-ADXL355 directories contain unfinished development work and should not be expected to build or function correctly.

Read seismometer/README.md before configuring the firmware. It documents the required NX-1D settings and the sensor-specific limitations of its compensation and high-pass filters.

Open the NX-1D directory as a PlatformIO project. Before uploading, review its include/settings.h and source files for Wi-Fi credentials, station identifiers, server address, sensor pins, and calibration values.

Build the NX-1D firmware from the command line:

cd seismometer/NX-1D
pio run

Connect the target ESP32 and upload with:

pio run --target upload
pio device monitor

Never commit real Wi-Fi credentials or other secrets. Keep local values in ignored files or inject them through PlatformIO build settings.

Development checks

The web application provides the currently configured automated checks:

cd nexaseis-web
npm run lint
npm run build

There is not yet an automated Python or firmware test suite. When changing the server, verify startup with a writable data_path and exercise the relevant input/output service.

License

NexaSeis is licensed under the GNU Affero General Public License v3.0.