Low-Cost Portable VO₂ Max Mask
Shashwat Sinha · Marcel Lab · Jun 2024 – Present
Abstract
This thesis presents the design, fabrication, and validation of a low-cost portable mask for real-time VO₂ max estimation during exercise. The system integrates O₂, CO₂, and differential pressure sensors on an ESP32 microcontroller with a custom Venturi tube housed in a 3D-printed modular enclosure. At approximately $222 BOM — less than 1% of commercial metabolic carts — the device aims to democratize access to cardiopulmonary exercise testing.
Embedded C++ firmware handles real-time sensor polling and dual-rate BLE streaming, while a companion Python pipeline performs breath detection, airflow computation, and metabolic rate calculation. Sensor verification and system validation test plans have been executed through controlled experiments; an IRB-approved human subject study is in preparation.
Key Contributions
- CAD-modeled and 3D-printed modular enclosure with custom Venturi tube design
- Hand-soldered sensor circuit: ESP32, O₂, CO₂, differential pressure on I2C bus
- Embedded C++ firmware for real-time polling and dual-rate BLE streaming
- Python data pipeline for breath detection, airflow computation, and metabolic rate calculation
- Full prototype at ~$222 BOM — less than 1% of commercial metabolic carts