Introduction

This blueprint demonstrates satellite (NTN) connectivity for the Particle M635e.

It can be configured in several modes: permanent satellite connection, cellular first then satellite fallback, or force switching between cellular and satellite, all the while publishing events to the Particle cloud.

It also doubles as an NTN diagnostic tool: verbose serial output reports satellite signal quality, eSIM profile switches, state transitions, and publish results, so you can evaluate satellite connectivity and antenna placement empirically.

Supported devices

Hardware and supplies

• Particle M635e (M-SoM with NTN support)
• NTN-capable antenna

Project description:

The M635e NTN blueprint demonstrates hybrid cellular (LTE-M) and satellite (NTN) connectivity on the Particle M635e, including eSIM profile switching between the LTE and NTN profiles.

Key Features:

• NTN (satellite) operation at a fixed location without GNSS
• Periodic publishing in both NTN and LTE-M mode
• LTE to NTN fallback when LTE publishes fail beyond a configured timeout or LTE connectivity is unavailable
• NTN to LTE recovery via periodic LTE retry
• eSIM profile switching between the LTE and NTN profiles
• A single publish abstraction that routes to LTE or NTN automatically, centralizing rate limiting (1 message / 30 s on NTN) and payload sizing (256-byte NTN limit)
• Verbose serial diagnostics for signal quality, satellite acquisition, state transitions, publish results, and timing estimates
• Simulated LTE loss mode for testing fallback without leaving coverage

All runtime behavior is configured through a single top-level env.json file, which Particle Workbench builds into the application binary as environment variables. The shipped configuration is NTN-first, so satellite behavior is demonstrated immediately. Switch to LTE-only, NTN-only, or a hybrid LTE-primary / NTN-fallback deployment pattern by editing env.json. NTN attach requires a location fix, which comes either from fixed coordinates or from the onboard GNSS engine.

Follow the guided instructions at setup.particle.io to install this blueprint and both LTE-M and NTN eSIM profiles on your device.

A clear view of the sky is essential for NTN connectivity. Initial satellite registration can take up to 10 minutes.

LED Behavior:

• Solid white: waiting for a serial connection at boot
• Solid green: searching for NTN signal
• Solid cyan: registered on NTN and connected to the Particle cloud
• Blinking green: search for LTE-M cellular signal
• Breathing cyan: registered on LTE-M and connected to the Particle cloud