Motherboard

Syringe-Based Breathing Simulator

University biomedical engineering project developed by Gruppo Viola: a motorized syringe generates controlled air flow at its outlet. The system combines a BLDC motor with an ESCON 50/5 drive, encoder feedback, Sensirion pressure or mass-flow sensing, PID control, BLE communication and a desktop monitoring GUI.

This repository presents the final ESP32-based system together with its electronics, control software, measurement data and technical documentation. Earlier firmware, interface and hardware iterations are preserved separately as supporting development history.

System overview

The final firmware runs on an ESP32 and coordinates:

• flow sensing through SDP810 or SFM3300 devices;
• motor control through the ESCON driver;
• incremental encoder feedback and homing signals;
• PID regulation of the generated flow;
• external SPI EEPROM storage;
• HM-10 compatible BLE telemetry and commands.

The final architecture is supported by a custom control board and a desktop BLE interface. Earlier STM32 and ESP32 bridge implementations are preserved as development iterations.

Repository map

The detailed working inventory is in docs/PROJECT_CATALOG.md.

Final system

• Controller: firmware/esp32/main coordinates sensing, encoder feedback, motor actuation, PID flow regulation, EEPROM storage and BLE communication.
• Control interface: software/gui/main_gui.py provides BLE discovery, connection management, real-time flow/position/PWM plots, operating modes, calibration controls, logging and emergency stop.
• Electronics: hardware/motherboard-r2 and hardware/pogo-adapter contain the KiCad designs for the control board and sensor adapter. The original motherboard design is preserved as motherboard-r1.
• Validation data: data/measurements/raw contains the experimental acquisitions used during characterization and analysis.

Communication status

The final ESP32 interface uses an HM-10-compatible BLE service (FFE0/FFE1) and telemetry frames in the form SNSR <flow> <encoder_position> <pwm>. The communication details are summarized in docs/protocol.md.

The earlier Nordic UART bridge and STM32 variants remain available in archive as development iterations and are not part of the primary ESP32 control path.

Running the Python tools

The main GUI requires Python packages including PyQt6, pyqtgraph, bleak and qasync. The BLE terminal declares its dependency in requirements-ble.txt.

The CSV visualizer is a separate Streamlit utility:

streamlit run software/tools/visualizer.py

Its expected columns are Timestamp_s and Pressione_Pa; the raw measurements commonly use Time_s and Pressure_Pa, so they are not directly interchangeable yet.

Firmware and hardware

The Arduino ESP32 sketch is located in firmware/esp32/main and uses the local NimBLE-Arduino library in firmware/esp32/libraries.

KiCad source files are separated from local state, backups and manufacturing exports. The root .gitignore excludes regenerable artifacts while keeping source schematics, PCB files, custom libraries and experimental measurements available for review.

Project documentation

• Project catalog
• Communication protocol notes
• Project report
• Code-flow diagram
• Firmware pseudocode
• Assembly render

Development history

Previous ESP32 sketches, STM32 firmware, BLE bridges and GUI prototypes are preserved in archive. They document the iterations that led to the final ESP32 architecture, while the project entrypoints above describe the system delivered by the team.