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Geoffrey Fournier edited this page Mar 20, 2026 · 13 revisions

LinKit v4 Core - Firmware Documentation

LinKit v4 Core is a multi-sensor wildlife tracker firmware running on nRF52840 (Nordic Semiconductor). It supports Argos satellite communication (KIM/SMD modules) and LoRaWAN (RAK3172-SiP) for tracking birds and marine animals with configurable sensors, underwater detection, geofencing zones, and low-battery management.

Features

  • GNSS - u-blox M10Q GPS with AssistNow Online/Offline, configurable dynamic models, HDOP/HACC filtering
  • Argos Satellite TX/RX - Pass prediction, legacy, duty cycle, and Doppler modes. Supports KIM2 (CLS) and SMD (Arribada, A+ protocol) modules
  • LoRaWAN - RAK3172-SiP module (Semtech SX1262), OTAA/ABP, EU868 (+ other bands), Class A/B/C
  • Pressure Sensor - LPS28DFW barometric pressure with altitude computation and configurable full scale (1260/4060 hPa)
  • Accelerometer - BMA400 3-axis with wakeup detection, activity monitoring, configurable measurement range
  • Thermistor - NTC temperature sensor with wakeup threshold
  • Underwater Detection - Saltwater switch (analog with auto-calibration, 5-level detection), pressure-based, GNSS-based
  • Geofencing Zones - Circular zone with out-of-zone detection and alternate Argos configuration
  • Low Battery Management - Configurable threshold with alternate GNSS/Argos parameters and critical shutdown
  • Camera - Optional camera trigger on surfaced/accelerometer wakeup events
  • Dive Mode - Dive state machine with reed switch pause/resume
  • Bird Mortality Detection (RSPB) - Automatic mortality confidence from activity, temperature, and GPS stationarity
  • 206 Configurable Parameters - Read/write via DTE commands over USB/BLE/UART
  • Sensor Data Logging - Per-sensor CSV-formatted flash logs with DUMPD retrieval
  • Sensor Data in TX - Configurable sensor data aggregation (oneshot/mean/median) appended to Argos/LoRa packets

Supported Boards

Board Communication Description
LinkIt V4 KIM Argos (KIM2, UART) Default Argos tracker with CLS module
LinkIt V4 SMD Argos (SMD, SPI) Arribada SMD module with A+ protocol and security
LinkIt V4 LoRa LoRaWAN (RAK3172) Terrestrial LPWAN for gateway-covered areas
RSPB Tracker Argos (SMD, SPI) Bird tracker with TPL5111 duty cycle wakeup

See Board Variants for detailed hardware specs, parameters, and configuration per board.

Hardware

  • MCU: nRF52840 (ARM Cortex-M4F, 1MB Flash, 256KB RAM)
  • SoftDevice: S140 v7.2.0 (BLE 5.0)
  • GPS: u-blox M10Q (UART)
  • Build System: CMake + ARM GCC Toolchain
  • Test Framework: CppUTest

Wiki Structure

  1. User Guide - Activate, configure, and deploy your tracker
  2. Developer Quick Start - Build firmware from source
  3. Building the Project - CMake configuration and build options
  4. Programming the Module - Flashing, debugging, DFU
  5. Board Variants - Hardware specs and configuration per board
  6. DTE Commands Reference - DTE protocol and commands
  7. Firmware Architecture - Code structure and design patterns
  8. Development Guide - Adding parameters, services, sensors
  9. Parameters Definition - All configurable parameters and their purpose
  10. Satellite Message Format - Argos & LoRa packet encoding, bit layouts, decoding
  11. LinkIt UW Behavior - Underwater mode, SWS algorithm, Argos TX modes
  12. RSPB Bird Tracker - TPL5111 duty cycling, battery modes, mortality detection
  13. SWS Algorithm - SWS analog detection algorithm deep-dive

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