Portable Breathalyzer Enclosure Design

I have a handheld H₂S breathalyzer heading into clinical trials and now need a production-intent enclosure. The device must present a traditional, professional look in beige and white—the palette hospitals already trust—and it has to survive the typical wipe-down regimen with alcohol and hospital-grade disinfectants. For this first prototype run I will print everything in PLA on our in-house FDM machine, so the geometry needs to honor FDM constraints: self-supporting angles, no critical surfaces steeper than 45°, sensible fillets instead of tiny radii, and walls that stay uniform so nothing warps. At the same time, every surface, draft angle, snap boss, and rib must already anticipate a future tool in ABS or PC-ABS. In other words, printability now, injection-moldability later. Key functional priorities • Easy-to-clean external surfaces with minimal crevices • A modular, service-friendly layout—board, sensor, and battery should come out without fighting hidden screws • Ergonomic handling for clinicians who will be gloved most of the time Deliverables 1. Production-ready 3D CAD (STEP) with clearly separated parts and draft notation 2. FDM-ready STL files for our prototype print farm 3. An exploded view or simple assembly guide that shows how the modules lock together and release for servicing 4. Short DFM notes highlighting wall thickness, snap deflection, and chemical-resistant material callouts If you can merge hospital-grade practicality with solid manufacturing foresight, this will move straight into our pilot run. Project Overview I am developing an innovative portable H₂S breathalyzer for clinical diagnostic applications and seeks an experienced CAD design engineer to create a production-ready medical device enclosure. This project requires sophisticated integration of gas sensing technology, embedded computing systems, and moisture management within a handheld medical diagnostic device. As a healthcare technology company specializing in diagnostic solutions, I require a design that meets rigorous medical device standards, incorporates complex gas flow dynamics, and maintains professional clinical aesthetics. The successful candidate will work directly with me (mechanical engineering/robotics background) and engineering team to ensure the design meets our technical specifications while maintaining manufacturability and regulatory compliance potential. This is not a simple electronics enclosure project - it requires advanced understanding of gas sampling systems, electrochemical sensor integration, moisture management, and medical device design principles. Complete Component Integration Requirements The enclosure must precisely integrate the following components with detailed specifications provided upon project commencement: Core Electronics Components: Primary Computing and Power: Raspberry Pi Zero 2 W: 65mm × 30mm × 5mm (requires thermal management and secure mounting) Seeed Studio LiPo Rider Plus: ~50mm × 23mm × 8mm (USB-C charging port external access required) 1500mAh PCM Protected Micro Li-Po Battery: ~60mm × 35mm × 5-7mm (secure retention system needed) 5MP Raspberry Pi Camera Module: 25mm × 24mm × 9mm (rigid mounting for user verification during sampling) Two Push Buttons: 6mm × 6mm tactile switches (ergonomic single-handed operation) Critical Gas Sensing System - SC05-H₂S Sensor: Sensor Specifications (Multiple Variants Exist): The design must accommodate SC05-H₂S sensor variants with flexible mounting system: Potential Dimensions: 20mm diameter × 16.5mm height OR 24mm × 20mm × 16mm rectangular Interface Options: Analog output (requiring ADS1115 ADC module) OR digital UART/I2C Power Requirements: 5-50mA depending on variant Environmental Sensitivity: Highly sensitive to direct moisture exposure and airflow velocity Critical Design Note: Exact sensor specifications must be verified before final design, requiring modular mounting approach to accommodate variants. Dual-Chamber Architecture Requirements Chamber A: Gas Sampling System (Isolated "Wet Zone") Airflow Path Engineering. Bottom Layer: 1500mAh battery with secure retention and foam padding Middle Layer: Raspberry Pi Zero 2 W with thermal management (passive ventilation required) Interface Layer: Power management board and optional ADC module Cable Management: Internal routing for camera ribbon cable and sensor wiring Thermal Management Requirements: CPU Cooling: Ventilation slots positioned above Raspberry Pi CPU location Air Circulation: Minimum 2mm clearance for convection cooling Heat Isolation: Prevent thermal influence on sensor chamber temperature User Interface and Ergonomics Control Interface: 1st Push Button: For Capturing the a photo 2nd Push Button: For Capturing H2s Sensor readings over a period of time. Status Indicators: LED visibility through light pipes or transparent windows Charging Port: USB-C access positioned for convenient charging Manufacturing and Assembly Specifications Primary Manufacturing: High-Quality 3D Printing Wall Thickness: 2.0-2.5mm minimum for structural integrity Tolerances: 0.2mm clearance for FDM printing, 0.1mm for SLA Assembly System: Two-part clamshell design with M2.5 screws and heat-set inserts Support-Free Design: Geometry minimizing support structures where possible Future Scalability: Injection Molding Compatibility Draft Angles: 2-3° minimum on vertical surfaces Uniform Wall Thickness: 2mm walls for consistent cooling Undercut Avoidance: Design compatible with two-part molds Material Requirements: Breath-Contact Surfaces: Medical-grade polypropylene (PP) or ABS Structural Components: PETG, ABS, or tough resin for 3D printing Sealing Components: Food-grade silicone O-rings and gaskets Required Qualifications Essential Requirements: Experience: 4+ years in medical device, diagnostic equipment, or sophisticated consumer electronics design CAD Proficiency: Expert-level SolidWorks or Fusion 360 with surfacing capabilities Specialized Knowledge: Gas flow or fluid dynamics in device design Medical device design principles and biocompatibility Moisture management in electronic devices Design for Manufacturing (DFM) for 3D printing and injection molding Highly Preferred: Breath analysis devices or respiratory diagnostic equipment experience Electrochemical sensor integration with environmental sensitivity understanding Regulatory compliance knowledge (FDA, CE marking, ISO 13485) CFD analysis capabilities for airflow validation Professional Attributes: Communication: Excellent written/verbal skills for technical collaboration Responsiveness: Daily progress updates during active design phases Problem-Solving: Proactive approach to technical challenges Quality Focus: Attention to detail ensuring manufacturable, robust designs Application Requirements Required Submission Materials: 1. Professional Portfolio: Submit 3-5 relevant projects demonstrating: Medical device or diagnostic equipment enclosure designs Handheld electronic devices with complex internal packaging Gas flow or fluid handling systems (if applicable) Design progression from concept through manufacturing 2. Technical Approach (500-600 words): Address your specific approach to: Dual-chamber architecture design SC05-H₂S sensor integration and moisture protection Thermal management for Raspberry Pi Manufacturing strategy balancing prototype and production needs 3. Project Proposal: Timeline: Schedule with specific milestones Pricing: Fixed project fee with phase breakdown Software: Primary CAD software and version Revision Policy: Included iterations vs. additional scope Communication Expectations: Progress Updates: During active design phases Video Reviews: Design reviews- 10 - 15 mins Availability: Overlap with India Standard Time preferred for synchronous communication Intellectual Property: All designs and documentation become exclusive property of Varun Cumbamangalam Designer retains portfolio rights with my approval Confidentiality agreement required before project commencement Future Opportunities: Successful completion may lead to ongoing collaboration including design iterations, manufacturing support, and additional product development for our companies expanding portfolio. This project offers the opportunity to contribute to meaningful healthcare technology innovation while working with an experienced, technically sophisticated engineering team. We seek a design partner who shares our commitment to engineering excellence, user-centered design, and creating products that make a real difference in clinical diagnostics.

Projektin tunnus (ID): 40160901