P13027: Portable Ventilator Team Leader: Megan O’Connell Matt Burkell Steve Digerardo David Herdzik Paulina Klimkiewicz Jake Leone
Overview Project Scope-Background 13026 Foundation slide Proposed redesign Customer Needs Engineering Specs Risk Assessment HOQ/QFD Diagram System Block Diagram Function Decomposition Pugh Diagrams Battery Pressure Sensors Circuit Board MCU CO2 Measurements CAD Visuals Usability Study at Imagine RIT Questions? 2 of43
Project Scope Project Objective: Improve the current design of P13026 Duration: 27 weeks Market Release: 2015 Budget: $1000 Customer: Jeff Gutterman Roman Press Faculty Mentor: Team: Edward Hanzlik 4 Mechanical Engineers 2 Electrical Engineers 3 of43
MEDIRESP III 13026 PEV 4 of43
From 13026 -> Our Foundation to Build On Updates: Electronic controls (decrease size/more options) Smaller pump Reliable and smaller battery (2+ hours) Device ergonomics and usability Additions: Ability to monitor and record vitals Pulse oximeter feedback Signaling alerts 5 of43
Revision B- Proposed Redesign Update: Battery Size-> Reduce Size & keep same capacity Reduce Circuit Board size-> Create custom board for all electrical connects Phase motor driver to a transistor Display Ergonomics Overall Size and shape of PEV Instruction manual Additions: Visual Animated Display-> Moving Vitals Memory capabilities USB extraction of Data Co2 Sensor as additional Feature to PEV Overload Condition due to Pump Malfunction 6 of43
Customer Needs 7 of43 Customer Need # Importance Description Comments/Status CN1 1 Maintain Portability Portable based on digital electronics, preferably on microprocessor, minimize weight and size CN2 Include Audio Feedback Gives non-visual, non-braille instructions/feedback CN3 Optimize Battery Life Operates for minimum of 2 hours without recharging CN4 Replaceable Battery Battery easily replaced CN5 Minimize Expenses Parts cost < $1000 CN6 Display Relevant Data Show information that will be necessary for the customer to operate the ventillator on the front panel CN7 2 Measure Oxygen Levels Add a pulse oximeter CN8 Measure CO2 Levels Measure CO2 levels on expiration CN9 Optimize for mass production CN10 3 Design Similarly The design of an updated version of the PEV that remains "substantially equivalent" to the design which received FDA 510(k) approval to manufacture and market CN11 Record and Transfer Data Record and transfer data CN12 Reduce size/weight (less than 18lbs) 7 of43 Importance: 3: Preference only 2: Nice to Have 1: Must Haves
Engineering Specifications Portable Emergency Ventilator Engineering Specifications - Revision 1 - 03/19/13 Specification Number Source Function Specification (Metric) Unit of Measure Marginal Value Ideal Value Comments / Status S1 PRP System Volume Control Liters 0.2 ± 0.2 S2 Breathing Rate BPM, Breaths per Minute 4 -15 S3 Pick Flow Liter/Min 15 - 60 S4 Air Assist Senitivity cm H20 0.5 ± 0.5 S5 High Pressure Alarm 10 - 70 S6 DC Input Volts 6 - 16 Due to battery, must be greater than 9V S7 DC Internal Battery 12 S8 Elasped Time Meter Hours 0 - 8000 S9 Pump Life 4500 S10 O2 / Air mixer O2 21% - 100 % S11 Secondary Pressure Relief 75 S12 Timed Backup BPM S13 Weight Kg ≤ 8 S14 Robustness Drop Height meter 1 8 of43
Risk Assessment 9 of43
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HOQ/QFD Diagram 11 of43
System Block Diagram 12 of43
Functional Decomposition 13 of43
Top Level Functions 14 of43
Provide Airflow 15 of43
Monitor Feedback 16 of43
Communicate State 17 of43
Manage Power 18 of43
Battery Selection Pugh Chart Battery Option Selection Option #1 Option #2 Option #3 Option #4 NiMH NiCd Li-Ion Li-Ion Polymer Selection Criteria Score Cost + - Weight Size Physical Durability Charge Loss Resistance to Environmental Effects Operating Conditions Sum +'s 1 2 4 Sum 0's 6 3 Sum -'s Net Score Rank 19 of43
Batteries: Lithium-Ion Polymer Very low profile - batteries resembling the profile of a credit card are feasible. Flexible form factor - any reasonable size can be found Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell. Improved safety - more resistant to overcharge; less chance for electrolyte leakage 20 of43
Flow Sensor Type Pugh Matrix Selection Criteria Option 1 (Original) Option 2 Option 3 Mass Flow Sensor Differential Pressure 2 Pressure Sensors Score Weight + Cost Physical Durability Accuracy Range Operating Temperature Size Sum +'s 4 Sum 0's 8 3 Sum -'s Net Score Rank 1 21 of43
Pneumatic Schematic 22 of43
Differential Pressure Sensor Model Inlet Filter PUMP Exit DP Pressure Sensor Pressure Sensor 23 of43
Two Pressure Sensors Model Inlet Filter PUMP Exit Pressure Sensor Pressure Sensor 24 of43
Pressure Sensor Pugh Matrix Selection Criteria Option 1 Option 2 Option 3 Option 4 FreeScale MPXV7007 FreeScale MPXV7002 FreeScale MPX12 Honeywell TruStability Score Weight Cost - + Physical Durability Compensated Accuracy Range Operating Temperature Size Sum +'s 5 4 2 1 Sum 0's 3 Sum -'s Net Score -2 Rank 25 of43
PCB Selection Pugh Chart PCB Structure Selection Option #1 Option #2 Option #3 Mediresp IV Mediresp III Custom PCB Selection Criteria Score Weight - + Cost Size Physical Durability Implementation Manufacturability Work Required Sum +s 2 4 Sum 0s 1 Sum -s Net Score -2 Rank 26 of43
Number of Analog inputs MCU Selection PUGH Manufacturer NXP ST Micro Freescale TI MCU LPC1769 STM32 K60 k70 Hercules Architecture ARM M3 ARM M4 ARM R4 Price $11 $16 $20 $30 Packaging -- Ease of programming - Cost Performance ++ + +++ Number of Analog inputs PGA Reliability Power usage Net Score 3 4 2 Rank 1 General Notes: All MCU rated for -40° to 105° C 27 of43
Data Transfer PUGH USB Mass Storage USB Device Bluetooth SD Ease of Development + - Security Usability Cost Net Score 3 1 -2 2 Rank 4 28 of43
LCD Interface: RGB vs Parallel Two different interfaces commonly used in LCD displays are RGB (no controller) and Parallel (built-in controller, ex. SSD1963) RGB Parallel (8080) Pins required for communication 26 (8 for each color, Vsync, Hsync) 13 (8 data, Rd, Wr, R/D, CS, RST) MCU requirements Requires LCD peripheral Any MCU with GPIO will work Refresh rate Limited to speed of MCU Limited to speed of controller (slower) Cost Cost of bare LCD (~$75 for 7”) Cost of RGB+$25 controller (~$100 for 7”) Status Unimplemented Implemented 29 of43
CO2 Sensor Pugh Matrix 30 of43
GE Sensing Telaire 6004 Co2 Sensor (~$25) Non-Permeable Seal NDIR Co2 Measurement Wiring Exhale From Patient ASCO Pneumatic Disposable In-line Filter Send Reading To PEV System MCU 31 of43
Housing Modifications Smaller components = smaller package 32 of43
Housing Modifications Old Physical Extremes: 15in long X 10in high X 7in deep Target Weight: 17 pounds New Physical Extremes: 11in long X 6.75in high X 7in deep Target Weight: 10 pounds 33 of43
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Usability Testing At Imagine RIT Goal: Gather data to understand the overall feasibility of the PEV user interface design and styling. Critical Components of Design: Overall Geometry Knob Controls and Display Knob Location Screen Location Screen Function- Vitals Display Verbage Clarity Color 41 of43
Usability Study Breakdown 1 2 3 INSTRUCTIONAL INTERACTION LIKERT SCALE RATING COMPONENT COMPARISON Goal: Gain user feedback from actual interaction with device. Gain a mass feedback on overall look and operation of the device. Understand and Maximize usability of critical user operated components. Guide user through medical scenario and operation. Instruct user to operate with system inputs Ask questions about the user/device interaction Conversational Feedback from direct system operation Create handout to be filled out by on-viewers Scaled rating (1-10) of critical components of design. Mass feedback from overall system aesthetic Knob Board Comparison with physical examples Overall geometry comparison (using David’s sketches) Original MEDIRESP III to MSD 13026 hands on part comparison Direct Feedback of liking to a specific individual component 42 of43
Interactive Knob Board Value displays on screen MEDIRESP III MEDIRESP IV Feedback: Which is easiest to use? Is there a distinction conflict in certain knob design? Opinion of overall aesthetic? 43 of43