IoT O2 Concentrator

IoT Oxygen Concentrator Integration

Purity Monitoring, Alert System and Compressor Control

A non-invasive integration module for PSA oxygen concentrators. The system monitors oxygen purity on the outlet line, escalates alerts through five tiers as purity drops, notifies a caregiver via SMS or voice call, and cuts compressor power only at true system failure levels.

What This System Does

The concentrator itself is not modified. All integration is external in a separate enclosure.

Hardware

Full wiring, schematic, and PCB layout are documented in docs/.

Project Structure

project-root/
├── firmware/               # Arduino sketch (.ino), config.h, portal_html.h
├── hardware/                # KiCad schematic, PCB layout, Gerber files
├── docs/                    # Full project documentation, diagrams, images
├── README.md                # This file
├── SETUP.md                 # Step-by-step setup guide for Arduino IDE
└── .gitignore

Alert Tiers

The system escalates through five tiers based on O2 purity. Only the DANGER tier and above place a voice call; only WARNING sends SMS. The compressor keeps running through every tier except CRITICAL — the design assumes a caregiver may not respond immediately, so oxygen delivery is only stopped once purity has effectively fallen to ambient air levels, at which point the compressor was providing no therapeutic value anyway.

Thresholds are runtime-adjustable (see Configuration below) and persist in NVS flash. Default fallback values live in firmware/config.h.

All alerts are suppressed for 30 seconds after boot to allow the sensor warm-up and GSM network registration to settle before any buzzer, SMS, or call can fire.

Input Modes

The system supports three interchangeable data sources, switchable at any time from the web portal without reflashing:

• Potentiometer — a physical demo knob on GPIO 34, mapped to 21%–95.6%
• WiFi — connect to the device's own captive portal and drag sliders for O2, flow, and temperature
• Sensor (boots here by default) — real UART2 data from the OCS-3FL2.0. If no real sensor is connected, the system runs a realistic warm-up illusion (ramping 21% → ~92% over ~15 seconds, then settling with slight jitter) so the full alert chain can be demonstrated with no hardware attached. The moment a real sensor sends valid packets, live data takes over automatically.

WiFi captive portal for demo input and caregiver configuration

Firmware Architecture

The firmware uses FreeRTOS (built into the ESP32 Arduino core — no extra install needed). Five tasks run concurrently, sharing data through two mutex-protected resources:

dataMutex protects the shared sensor reading; modemMutex protects all TinyGSM AT command calls, since multiple tasks share the same SIM800L UART.

Quick Start

See SETUP.md for the full step-by-step setup guide.

1. Install Arduino IDE 2.x
2. Add ESP32 board support
3. Install required libraries (listed in SETUP.md — includes ESPAsyncWebServer for the portal)
4. Open firmware/IoT_O2_Concentrator.ino
5. Set board to ESP32 Dev Module, select your COM port
6. Upload

Configuration: Thresholds and Caregiver Number

Three interchangeable ways to configure the system — all write to the same NVS storage:

1. Web portal (easiest, works in any input mode) Connect to WiFi network O2-Controller (password 12345678), a captive portal should open automatically. Enter the caregiver number in the "Caregiver Number" card and tap Set.

2. USB Serial (115200 baud)

SET NUM +2348012345678
SET WARN 72
SET NORM 87
STATUS
HELP

3. SMS to the device SIM Send the same commands as SMS text to the SIM card installed in the SIM800L EVB. The device replies with confirmation and deletes the processed message.

Caregiver receiving a live SMS alert

All three methods are always available regardless of which input mode (pot/WiFi/sensor) is active.

Documentation

Full design documentation is in the docs/ folder. It covers:

• System architecture and power design
• Sensor UART protocol and 12-byte packet parsing
• Relay driver circuit (NPN, active-HIGH from GPIO)
• Five-tier alert logic and state machine
• KiCad schematic and PCB layout
• Wiring connection reference table
• Bill of Materials

Project by Smart Ayodele. README last updated to match firmware Rev 1.4