Skip to content

Firmware Overview

Welcome

The CICERONE AirLink firmware is an embedded system designed for continuous indoor air quality monitoring with remote telemonitoring capabilities. Built on the Arduino framework for the Nano 33 BLE Sense Rev2, it implements a non-blocking, timer-based architecture that ensures reliable data collection and transmission.

Key Features

  • Non-Blocking Architecture

    Dual-timer system with 5-second sensor sampling and 10-minute data averaging cycles.

  • Multi-Sensor Integration

    SEN54 (PM/VOC), T6793-5K (CO₂), and DS3231M RTC for comprehensive air quality monitoring.

  • NB-IoT Connectivity

    Optional wireless data transmission via SIM7020G module with HTTP POST.

  • Modular Design

    Clean separation of concerns with dedicated APIs for each component.

  • Debug System

    Multi-level logging framework with per-module configuration.

  • Memory Efficient

    Static allocation, minimal dynamic strings, optimized for long-term deployment.

Documentation Sections

Architecture

Learn about the system architecture, modular component structure, data flow pipeline, and memory management strategies.

Topics covered:

  • Non-blocking timer system (5s and 10min)
  • Module organization and dependencies
  • Data accumulation and averaging
  • Conditional compilation for feature control

Read Architecture Documentation

Program Flow

Understand the detailed execution flow from device startup through continuous operation.

Topics covered:

  • Setup phase initialization sequence
  • Main loop structure and timing
  • 5-second data acquisition cycle
  • 10-minute averaging and transmission cycle

Read Program Flow Documentation

Sensor Interfaces

Explore sensor communication protocols, specifications, and calibration procedures.

Topics covered:

  • SEN54 particulate matter and VOC sensor
  • T6793-5K CO₂ sensor with ABC algorithm
  • DS3231M real-time clock with battery backup
  • I2C bus configuration and troubleshooting

Read Sensor Documentation

Data Transmission

Discover how data is formatted and transmitted via NB-IoT cellular connectivity.

Topics covered:

  • JSON packet format and generation
  • NB-IoT communication protocol (SIM7020G)
  • AT command sequences
  • Power consumption optimization

Read Transmission Documentation

Quick Start

Building and Uploading

# Compile firmware
arduino-cli compile --profile nano33ble --build-path firmware/build firmware/

# Upload to board
arduino-cli upload --profile nano33ble --input-dir firmware/build

# Monitor serial output
arduino-cli monitor -p COM3 -c baudrate=115200

See the project README for detailed build instructions.

Configuration

Before uploading, configure the device in firmware/Configuracion.h:

#define ID_USUARIO "AIRLINK_01"              // Device ID
#define HABILITAR_NBIOT 1                     // Enable NB-IoT
#define SERVIDOR_IP "http://example.com"      // Server URL
#define APN_NBIOT "iot.1nce.net"              // Network APN

See Firmware Configuration Guide for detailed configuration options.

Debug Output

Enable debug output in firmware/Debug.h:

#define DEBUG_LEVEL 3        // 0-4 (0=disabled, 3=recommended)
#define DEBUG_SEN5X 3        // Per-module debug levels
#define DEBUG_NBIOT 3

See Debug Configuration Guide for debugging options.

Technical Specifications

Parameter Value Notes
Platform Arduino Mbed OS Nano Nano 33 BLE Sense Rev2
Language C/C++ Arduino framework
Compiler GCC ARM Via Arduino CLI
Flash Memory ~100-150 KB Depends on enabled modules
RAM Usage ~20-30 KB Dynamic allocation minimal
Sampling Rate 5 seconds Configurable in code
Averaging Period 10 minutes 120 samples per average
Transmission Interval 10 minutes 144 transmissions/day
Power Consumption ~120-180 mA Average (5V input)
Battery Life ~5 hours With 900 mAh battery + NB-IoT

API Reference

Complete API documentation is available through Doxygen-generated references:

API Documentation - Generated from firmware/ source code

The API documentation includes:

  • Function prototypes and parameters
  • Variable definitions and usage
  • Module dependencies
  • Code examples
  • Implementation notes

Additional Resources

Configuration Guides

Hardware Documentation

Project Resources

License

The firmware is licensed under the GNU General Public License v3.0 or later.

See LICENSE.md for full license text.