Arduino / ESP32 library for SST Sensing LuminOx optical oxygen sensors
(LOX-01, LOX-02, and compatible variants – luminescence quenching technology)

• UART 9600 8N1 (factory default – only supported baud rate)
• Poll mode (M 1) – recommended for reliable communication
• Automatic detection of LOX-01 vs LOX-02
• Parses full A command response:
  • ppO₂ (mbar)
  • O₂ concentration (%) – LOX-02 only
  • Temperature (°C)
  • Barometric pressure (mbar) – LOX-02 only
  • Status code (0000 = good)
• Sensor identity commands (#0 manufacture date, #1 serial, #2 firmware)
• Timeout handling + retry mechanism
• Debug output option
• Works with ESP32, Arduino Uno, Mega, etc.

Notes from datasheet:

• Factory calibrated – recalibration may be required after extreme temperature fluctuations
• Housing can be cleaned with a damp cloth – do NOT immerse
• Contains no hazardous materials – RoHS & REACH compliant
• Maintenance-free (non-depleting sensing principle)

4-pin connector (2.54 mm / 0.1" grid, gold-plated)

ESP32 example (using UART2):

• Pin 3 (TX) → GPIO 16 (RX)
• Pin 4 (RX) → GPIO 17 (TX)

Important cautions:

• Always apply power to pins 1 & 2 beforeattempting communication
• Use ESD precautions when handling
• Recommended soldering iron temperature: ≤ 370 °C for < 5 s
• Do NOT solder directly to pins without the PCB washing process

**Installation

1. Download or clone this repository
2. Copy folder LuminOx to your Arduino libraries directory
   (~/Documents/Arduino/libraries/ or equivalent)
3. Restart Arduino IDE

Library should now appear in Sketch → Include Library → LuminOx

** Basic Example

#include <LuminOx.h>

// ESP32 UART2 example
HardwareSerial SensorSerial(2);
LuminOx ox(SensorSerial);

void setup() {
  Serial.begin(115200);
  delay(400);

  // RX=16, TX=17
  SensorSerial.begin(9600, SERIAL_8N1, 16, 17);

  Serial.println("\nLuminOx O₂ Sensor Test\n");

  ox.setDebug(true);     // optional: more verbose output
  ox.begin();            // sets poll mode + shows sensor info
}

void loop() {
  LuminOxReading r;

  if (ox.readAll(r)) {
    Serial.printf("O₂       : %.2f %%\n", r.o2_percent);
    Serial.printf("ppO₂     : %.1f mbar\n", r.ppO2_mbar);
    Serial.printf("Temp     : %.1f °C\n",   r.temperature_C);

    if (r.pressure_mbar >= 0)
      Serial.printf("Pressure : %.0f mbar\n", r.pressure_mbar);

    Serial.printf("Status   : %s (%s)\n\n", r.valid ? "GOOD" : "ERROR", r.status.c_str());
  } else {
    Serial.print("Error: ");
    Serial.println(r.error.isEmpty() ? "no valid response" : r.error);
    Serial.println("Raw: " + r.raw + "\n");
  }

  delay(2500);
}

**References

Official datasheet: DS-0030 REV 14 – LuminOx O₂ Sensors User's Guide: UG-001 – LuminOx Communication Protocol Manufacturer: SST Sensing Technical support: technical@sstsensing.com | +44 (0)1236 459 020

Feedback, bug reports, and pull requests are welcome! Made with love in India · 2025–2026