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P13027: Portable Ventilator

P13027: Portable Ventilator. Team Leader: Megan O’Connell Matt Burkell Steve Digerardo David Herdzik Paulina Klimkiewicz Jake Leone. Technical Review Overview. Engineering Specs Proposed redesign Battery and Power Calculations Power: Electrical Electric Board Layout SPO2 Sensor

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P13027: Portable Ventilator

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  1. P13027: Portable Ventilator Team Leader: Megan O’Connell Matt Burkell Steve Digerardo David Herdzik Paulina Klimkiewicz Jake Leone 1 of 75

  2. Technical Review Overview • Engineering Specs • Proposed redesign • Battery and Power Calculations • Power: Electrical • Electric Board Layout • SPO2 Sensor • CO2 Sensor • Pneumatic Design • Pressure Sensor Testing • Housing Vision-Casing Structure • Project Comparison • System Testing • BOM • Risk Assessment • Project Passover • Questions? 2 of 75

  3. Engineering Specifications 3 of 75

  4. Revision B- Proposed Redesign Update: • Battery Size-> Reduce Size & keep same capacity • Reduce Circuit Board size-> Create custom board for all electrical connects • Reduce Electrical Drive Motor • Display Ergonomics • Reduce Size and weight of PEV • Instruction manual Additions: • Visual Animated Display-> Moving Vitals • Memory capabilities • USB extraction of Data • Co2 Sensor as additional Feature to PEV • Mechanical Overload Condition due to Pump Malfunction 4 of 75

  5. Battery Choice: Tenergy Li-Ion • 14.8 V • 4400mAh • 0.8375 lbs • 7.35cm x 7.1cm x 3.75cm • Rechargeable up to 500 times • Price: $50.99 • Bulk pricing • Each cell: $3.18 = $25.44 (8 cells) • $10 Protection Circuit Module • ~$40 with packaging and connectors 5 of 75

  6. Power Calculation 6 of 75

  7. Charger (Brick) • HP AC Adapter • 18.5V • 3.5Amps • Power: 65W • Max power: 70W • Price: $14.35 (Amazon) • Bulk pricing: $6.48 when quantity of 1000 is bought 7 of 75

  8. DC-DC Boost ConverterT.I. TPS55340 8 of 75

  9. Component Calculations • Designed for Vin = 12-18V, Vout=18V, Iout= 2.5A • Most components were chosen using TI’s WEBENCH component selection tool • Calculating RFREQ • RFREQ(kΩ) = 57500 × ƒsw(kHz)-1.03 • Calculating minimum Inductance required for CCM 9 of 75

  10. Voltage Regulation • Input and output capacitors were chosen with regard to values on datasheets. 10 of 75

  11. Battery Charging Circuit • Suggested Solution: 11 of 75

  12. Our Solution 12 of 75

  13. Battery Charging Circuit • Many discrete components suggested by proposed solution were used • Determining the values of R8 and R9: • Timing Capacitors changed in order to set longer charging times for larger battery • Thermistor not needed for our application, replaced with resistor. • Current sense resistors set by: IFSS = 0.1V/R12 and IFSI = 0.2V/R18 • Dual-channel Power MOSFET chosen for power switch – rated well for our application • All components chosen with safety margins in order to achieve proper operation 13 of 75

  14. Electrical Schematics • Refer to Electrical Schematics (confidential) 14 of 75

  15. Revised Board Layout 15 of 75

  16. Connections to PCB • User Inputs Sensors LCD • and Power and Audio 16 of 75

  17. SpO2Sensor • Difference in Absorption between Red and Infrared is used to determine SpO2 17 of 75

  18. SpO2 Sensor Continued Simplified Design: 18 of 75

  19. SpO2 Flow Chart 19 of 75 Source: Freescale Pulse Oximeter Fundamentals and Design

  20. CO2 Sensor 1. Original Target -> Telaire 6004 OEM Module Problem: Supplier went out of business, similar models are not being sold by GE Sensing 2. GE SENSING: Does not sell CO2 OEM Module within concentration range needed Upon Further Investigation: The average exhale returns ~ 40,000 ppm of CO2 Dollar Range for CO2 OEM Concentration Modules (using NDIR) 20 of 75

  21. Cheapest option:CO2 Meter- K-30 10% CO2 Sensor • Cost $249 for 1 • $163 for 250+ • Programmable Range: 0-100,000 ppm • Accuracy: ± 30 ppm ± 3 % of measured value (up to 3% CO2) • Sensor Life Expectancy: > 15 years • Sampling Method: Diffusion • Current Consumption: 40 mA average • Simple analogue output sensor transmitter signal directed to OUT1 and OUT2 21 of 75

  22. Electrical Bill of Materials • Total Cost: • For 1: $311.94 • For 100: $193.43 • (This includes PCB, MCU, Sensors, and LCD) • Refer to Electrical BOM for complete parts list (confidential) 22 of 75

  23. Initial Test Plan for PCB AssemblyWeeks 1 and 2: PCB Assembly • First two weeks will be spent soldering PCB. • Check that all pads match component footprints • If any component(s) do not match footprint, attempt to solder jumper wire to pins. • If jumper wire is not possible or if component overlaps another component, make changes to PCB and reorder (2 week lead time +$66) • Solder components in CIMS using heat gun and solder paste. Larger components such as connectors will be hand-soldered 23 of 75

  24. Week 3: Power System I and Hello World Program Power System I: Powered from only external or only Battery • Apply 18V to external input power using Lab Power Supply. Set Current Limit to 500 mA to prevent damage to circuits. • Measure voltage on 10V, 5V and 3.3V nodes to confirm outputs are as expected. • Disconnect external power and connect charged battery. • Measure voltage on 10V, 5V and 3.3V nodes to confirm outputs are as expected. Hello World Program: • Plug in JTAG connector. Ensure correct orientation. • Test to see if JTAG Debugger has connection to MCU. • Download Test Program to MCU. • Connect LED to output pin. LED should start blinking. 24 of 75

  25. Week 4: Power Systems II Motor Drive Testing Power Systems II: Battery Charging and various DC inputs • Connect depleted battery and attach oscilloscope across battery and battery current sense resistor. • Apply external Power with Current Limit set to 2.5 A. • Observe that current stays less than or equal to 2 A and voltage on battery steadily increases up to but not over 16.8V. Monitor battery temperatures and discontinue temperatures if battery exceeds 110 F in Ambient. Motor Drive Testing: • Download PWM program to MCU • With Motor Disconnected, observe proper pulsing from MOT_PWM • Connect Motor • Test Motor from DC=.05 to DC=.66 25 of 75

  26. Initial Testing 26 of 75

  27. Initial Testing- Differential Pressure Sensor Model 27 of 75

  28. Differential Pressure Sensor • System Architecture • No Capacitor • No Backpressure

  29. Differential Pressure Sensor • Capacitor • Backpressure 29 of 75

  30. Static Pressure Sensor • System Architecture • No Capacitor • No Backpressure 30 of 75

  31. Screen Shots • System Architecture DP Sensor GP Sensor 31 of 75

  32. Screen Shots • Mechanical Capacitor DP Sensor GP Sensor 32 of 75

  33. Screen Shots • Electrical RC Circuit • 10 kΩ Resistor • Capacitor 100 μF DP Sensor 33 of 75

  34. Screen Shots DP Sensor GP Sensor • Results of temporarily resisting flow and then releasing • Pressure builds • Flow spikes and then quickly levels 34 of 75

  35. Video Proof • Impact of mechanical capacitor in system • Flow speed • Sensor dampening • Proof of flow sensor accuracy Conversion of Mechanical Flow Sensor: Cheat: 12 = 20 l/min 35 of 75

  36. Human Trials- • Determine if sensor can observe human backpressure • System Architecture • No Capacitor 36 of 75

  37. Mechanical Relief Valve Pressure Release at 1 psi  Reusable 37 of 75

  38. Rough Correlation to Factory Specifications • System Pressure 0-4.5 kPa (0-.65 psi) • Patient Pressure 0.5-2kPa (.07-.29 psi) 38 of 75

  39. Concerns- Calibration • Currently have no way of measuring pressure accurately • Mechanical gauge cannot handle pulsation • Uncertainty as to whether we can calibrate against another digital sensor 39 of 75

  40. Housing Modifications • 13026 Physical Extremes: • 15in long X 10in high X 7in deep • Projected 13027 Physical Extremes: • 12in long X 7.5in high X 7in deep Team: 13026 Team: 13027 40 of 75

  41. Housing Vision 41 of 75

  42. Housing Vision Speaker Mode O2 Sensor port CPR Compression # CO2 Sensor port Manual Mask tube ports Power 42 of 75 BPM Flow Rate Pressure Limit

  43. Housing Vision 43 of 75

  44. Housing Vision 44 of 75

  45. Housing Vision 45 of 75

  46. Housing Vision 46 of 75

  47. Project Comparison GOAL: Analyze the size and weight reduction between major contributing components of MSD 13026 PEV to our projected design. 47 of 75

  48. Summary: 48 of 75

  49. Casing Assembly Material: Plastic, Styrene for molding with rubber soles to protect damaging case Goal: Create an enclosed structure for our system components. Problem: Limiting the capabilities to ability/ access vacuum molding machine to produce similar appearance result as MSD 13026 49 of 75

  50. Option 1- Recruit RIT Industrial Design Major to recreate vision Option 2- Create a paneled assembly from plastic • Cons: • - Visual appearance would degrade • - Casing would not be seamlessly enclosed • Expense for sheet plastic • (ranges from $50-$200 based on thickness) Option 3- Purchase premade casing • Cons: • - Visual appearance would degrade • Casing would make entire device be larger & heavier than intended • Expense (~$158)

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