🫁 Zaphyr - Frugal Arduino / ESP32-based Spirometer

Zaphyr is a startup project aiming to develop a low-cost (frugal) spirometer for low-resource environments. It combines a differential pressure sensor (MXP5010DP), a microcontroller (ESP32), and an advanced Python script to acquire, process, and analyze patients' respiratory data to assist in the diagnosis of pulmonary diseases.

✨ Key Features

• High-Frequency Acquisition: Precise sampling at 1000 Hz for 10 seconds via the ESP32.
• Advanced Signal Processing: * Dynamic cut-off frequency calculation using Fast Fourier Transform (FFT).
  • 4th-order low-pass Butterworth filtering with zero-phase distortion.
• Fluid Mechanics: Conversion of pressure to volumetric flow rate (Bernoulli's Principle) with dynamic compensation for friction-induced pressure drops (Solving the Colebrook-White equation).
• Automated Clinical Analysis: * Extraction of standard parameters: FVC (Forced Vital Capacity), FEV1 (Forced Expiratory Volume in 1 second), PEF (Peak Expiratory Flow).
  • Calculation of the Tiffeneau-Pinelli index (FEV1/FVC ratio).
  • Generation of a pre-diagnosis (normal, obstructive, or restrictive profile) by comparing results to theoretical values based on the patient's age, gender, and height.
• Medical Visualization: Automatic generation of standard spirometry curves (Volume-Time and Flow-Volume graphs).
• Simulation Mode: Built-in data generator simulating different clinical profiles to test the software without physical hardware.

🛠️ Hardware Requirements

• Microcontroller: ESP32 board (or compatible Arduino).
• Sensor: MXP5010DP differential pressure sensor.
• Mechanics: 3D-printed spirometry tube (Venturi effect with R1 = 13.9mm and R2 = 4.9mm).

📁 Project Architecture

• codeArduino/codeArduino.ino: Embedded script for the ESP32. Handles the 12-bit ADC, strict timing (1 ms), and serial communication at 115200 bauds.
• zaphire.py: Main Python script running on the computer. Manages serial communication, mathematical processing (Numpy/Scipy), console user interface, and graph plotting (Matplotlib).
• A_frugal_arduino-based_spirometer_for_low-resource.pdf: Documentation and research associated with the project.

🚀 Installation & Usage

1. Hardware Setup (ESP32)

1. Open codeArduino.ino in the Arduino IDE.
2. Connect the Vout pin of your sensor to pin 34 of the ESP32 (can be modified in the code).
3. Upload the code to the board.

2. Software Setup (Python)

Ensure Python 3 is installed. Install the required dependencies:

pip install pyserial numpy scipy matplotlib

3. Running the Analysis

1. Connect the ESP32 to your computer via USB.
2. Identify your board's port:
   • Windows: COM3, COM4, etc. (Check Device Manager).
   • Mac/OSX: /dev/tty.usbserial-... or /dev/cu.usbserial-...
3. If necessary, modify the port parameter in the acquerir_donnees_serie() function at the bottom of the zaphire.py file.
4. Run the script:

python zaphire.py

5. Follow the on-screen instructions (enter the patient's data, then blow into the tube when prompted!).

💡 Tip: To test the code without the ESP32, comment out the serial acquisition line in the main block (__main__) and uncomment the generer_donnees_simulees(profil="obstructif") function.

✍️ Author

• Echchorfi Charaf - Computer Science and Information Systems Engineering student - UIASS