Grow Smarter v2

gs-node-esp is the firmware for a LoRa-based mesh networking node designed for low-power, long-range telemetry and communication. It runs on the ESP32-C6 SoC and integrates a bunch of environmental sensors, power management ICs, and a GPS module, and a custom mesh protocol.

System Architecture

Hardware Stack

The system is built around a shared I2C bus architecture managed by a multiplexer to support address-conflicting sensors and power domains.

• MCU: ESP32-C6

• Radio: SX1262 (LoRa)

• Power Management: BQ25798

• IO Expansion: MCP23017 (16-bit GPIO Expander)

• Timekeeping: DS3231 (RTC)

• Sensors:

  • BME280: Temperature, Humidity, Pressure
  • VEML7700: Ambient Light Sensor
  • ADS1115: ADC for analog sensors
    • Capacitive Soil moisture
  • DS18B20: Soil temperature

• GPS: UART-based GPS module (power controlled via MCP23017)

• Bus Management: TCA9548A I2C Multiplexer

Software Architecture

The project follows the ESP-IDF component-based structure.

• main/: Entry point and application-level logic.
  • main.c: System boot, logging, and task spawning.
  • app/: High-level application modules (Peripheral init, Battery Monitor, Interrupt Dispatcher).
    • app_self_test: Self-test hardware and build a sample packet stream.
    • test_mode: Tests LoRa communication.
• components/: Reusable drivers and system modules.
  • Drivers: sx126x_driver, bq25798, ds3231, mcp23017, bme280, veml7700, ads1115, gps_uart.
  • System: i2c_handler (Bus locking), app_devices (Shared handles), app_nvs, app_littlefs.
  • Mesh/Logic: packets (Protocol definitions), node_sync_store, node_distance_map.

Features

• Mesh Networking: Custom LoRa mesh protocol (docs/mesh_packet_protocol.md) supporting fragmentation, reliability, and flooding. Not currently implemented
• Power Management: Active monitoring of battery state and charger telemetry via battery_monitor_task.
• Interrupt Handling: Centralized interrupt_dispatcher to handle GPIO events from the radio, charger, and IO expander efficiently.
• Persistent Storage:
  • LittleFS: Stores node synchronization data and logs.
  • NVS: Stores configuration flags (e.g., INSTALLED status).
• GPS Integration: Daily GPS sync task for location and time correction.

Project Status

Implemented

• Peripheral Drivers: Full support for all hardware components (Sensors, RTC, Charger, Radio).
• I2C Management: Robust bus locking and multiplexer handling (i2c_handler, tca9548a).
• Protocol: Packet encoding/decoding, frame layout, and basic types defined.
• Interrupts Shared ISR handling for MCP23017 and direct GPIOs.
• Storage: LittleFS and NVS wrappers are functional.
• Self-Test: Basic smoke tests for sensors and radio.

In Progress / To Do

• Full Mesh Routing: The routing logic (A* using distance and SNR as H-costs) and dynamic pathfinding
• Install Flow: The "Mesh INSTALL" sequence (GPS sync -> Broadcast -> ACK -> Persist); first-time setup.
• Production Payload: Finalizing the sensor data payload structure for the mesh.
• Switch to LR-FHSS: Write a parser for the LR-FHSS packets.