The goal of the UNTAMED Data Logger is to enable accurate and continuous collection of sensor and positional data throughout our entire Indian Ocean expedition, regardless of connectivity.

The system is built around the ESP32-S3 microcontroller, selected for its wireless capabilities, processing performance, and rich peripheral support. It collects a variety of environmental and motion parameters using the following sensors:

• A 9-DoF IMU (Inertial Measurement Unit) to capture boat motion and orientation (pitch, roll, vibration)

• High-accuracy ultrasonic wind sensor

• GPS receiver with integrated real-time clock

• Waterproof DS18B20 digital temperature sensor

• 1.12” monochrome OLED display for real-time diagnostics

All data is logged to a microSD card in a custom format called RobinLog, optimized for compactness and compatibility with scientific data pipelines. Each data packet is timestamped using synchronized UNIX epoch and millisecond offsets, ensuring high-resolution time tracking for sensors with higher sampling rates (e.g. IMU).

The system is powered by a 10050 mAh lithium-ion battery and charged via solar power using a BQ24074 charger IC. Power efficiency is a core design principle, with firmware-level features such as CPU frequency scaling, radio shutdown, and write-buffered SD operations.

Designed for rugged marine use, the logger is housed in a waterproof case with passive cooling. It has undergone full calibration, battery optimization, and field testing to ensure durability and accuracy at sea.

This system was developed in close collaboration with the University of Western Australia (UWA), PhD candidate Rick de Kreij and Professor Phil Watson. Early works and sensor selection were supported by Paul Price (SmartBee Designs, USA). Final hardware design, embedded firmware development, system integration, production-ready assembly and validation were carried out by HardwareX (Cyprus).

The UNTAMED logger records:

• Wind speed and direction

• GPS location, heading, and speed

• IMU motion data (pitch, roll, tilt, vibration)

• Water temperature (with plans to expand to include air temperature, humidity, and barometric pressure)

Logging frequencies vary by sensor (typically 1–10 Hz), and the system is built for uninterrupted 24/7 operation powered by solar energy.

This project is a unique example of cooperation between adventurers, engineers, and scientists. The data collected will be shared with UWA to support research into:

• Indian Ocean surface dynamics

• Environmental impact on human endurance

• Ocean drift and weather modeling

We believe this will be one of the most detailed sensor datasets ever recorded from a human-powered expedition in the Indian Ocean. It will provide valuable insights for future explorers, oceanographers, and endurance researchers.