This project details the design, construction, and implementation of a compact, portable breathalyzer. The device utilizes an Arduino microcontroller, an MQ-3 alcohol sensor module, and an OLED screen to provide real-time Blood Alcohol Content (BAC) estimations. All components are housed in a custom 3D-printed enclosure.
The primary objective was to engineer a low-cost, easy-to-use, and portable device capable of providing rapid BAC readings. The project integrates embedded electronics, sensor data processing, and 3D design to create a functional prototype. The system was developed to be calibrated and tested for accuracy across different conditions.
- Alcohol Concentration Sensing: Utilizes an MQ-3 alcohol sensor to accurately detect ethanol concentrations from a user's breath.
- Real-Time BAC Calculation: The Arduino processes the analog sensor data and converts it into an estimated BAC value using a calibrated algorithm.
- Instantaneous Data Display: A 0.96" OLED screen provides immediate user feedback, displaying system status and the final calculated BAC reading.
- Software-Based Calibration: The firmware includes a calibration mode, allowing for fine-tuning of the sensor's baseline and sensitivity to improve accuracy.
- Portable, Self-Contained Design: The custom 3D-printed enclosure houses all components, including a portable battery supply, for field use.
| Component | Purpose |
|---|---|
| Arduino Uno | Core microcontroller for processing sensor data and control logic |
| MQ-3 Alcohol Sensor | Detects alcohol concentration in breath vapor |
| 0.96" OLED Display | Displays prompts and calculated BAC results |
| 3D-Printed Enclosure | Provides a custom, ergonomic housing for all components |
- Firmware: Developed in C/C++ using the Arduino IDE.
- Data Acquisition: The software reads raw analog voltage data from the MQ-3 sensor.
- BAC Conversion: A dedicated function converts the sensor readings into an estimated BAC value.
- User Interface: Manages all output to the OLED screen, guiding the user and displaying results.
- Calibration & Thresholds: Includes logic for adjusting sensor thresholds and calibration settings.
The device enclosure was modeled using Fusion 360. The design was optimized for ergonomics, ease of assembly, and proper airflow for the sensor. The components were fabricated using Fused Deposition Modeling (FDM) on a desktop 3D printer.
