Sentinel ESP32 Hardware Firmware

This repository contains the firmware and hardware documentation for the Sentinel project, based on LilyGO ESP32-S3 and compatible boards. The system is designed for sensor data acquisition, wireless communication, and remote monitoring in challenging environments.

Features

• Multi-sensor support:
  • Accelerometer (MPU9250/MPU6500) - Fall detection, steps counting
  • Temperature & Humidity (DHT22)
  • Gas detection (MQ2)
  • Battery monitoring
  • Heart rate monitoring (Polar H9 via Bluetooth)
• Wireless communication:
  • WiFi with automatic LTE fallback - Seamlessly switches to LTE when WiFi is unavailable
  • LTE/4G (TinyGSM)
  • Bluetooth Low Energy (NimBLE)
  • GPS (TinyGPSPlus)
• Modular FreeRTOS tasks for sensor reading, communication, and processing
• 3D-printable case design (see Prototype-design/Case-design/Format-for-3D-printing/)
• PlatformIO project for easy build and deployment

Hardware Requirements

• LilyGO T-SIM7670G S3 or T-A7670 (ESP32-S3/ESP32)
• DHT22 sensor
• MQ2 gas sensor
• MPU9250/MPU6500 accelerometer
• LiPo battery (with voltage divider for monitoring)
• Optional: Polar H9 heart rate strap (Bluetooth)

See LilyGO T-A76XX repo and include/utilities.h for supported board variants and pinouts.

Software Dependencies

• PlatformIO
• Arduino framework
• Libraries (see platformio.ini):
  • DHT sensor library
  • MQUnifiedsensor
  • NimBLE-Arduino
  • MPU9250_WE
  • TinyGSM (in lib/)
  • TinyGPSPlus (in lib/)

Getting Started

1. Clone this repository

2. Install PlatformIO (VSCode extension or CLI)

3. Connect your ESP32 board

4. Configure board and secrets:

   • Edit platformio.ini to select your board/environment
   • Copy include/secrets.h.default to include/secrets.h and configure your network credentials
   • Review include/config.h for additional system configuration options

5. Build and upload:

   pio run -t upload

6. Monitor serial output:

   pio device monitor

Directory Structure

• src/ - Main application source code (tasks, sensors, network)
• include/ - Header files and configuration
• lib/ - External libraries (TinyGSM, TinyGPSPlus)
• Prototype-design/Case-design/Format-for-3D-printing/ - 3D-printable case files (STL)
• docs/ - Documentation, diagrams, and pinouts
• scripts/ - API developing scripts

Documentation & Resources

• LilyGO T-A76XX hardware repo
• TinyGSM library
• TinyGPSPlus library
• 3D case: Prototype-design/Case-design/Format-for-3D-printing/Base-prototype-v1/Project_Sentinel_Base_Prototype v.1.stl
• Class diagram
• Pinout: T-SIM7670G-S3, T-A7670
• Systemdevelopers Retrospective

Project

For our hardware

License

This project is licensed under the MIT License. See LICENSE for details.