156B Week 8

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Analysis

  • Pressure comparison. In-body vs measured by transducer

    • Design of accompanying tests also necessary

  • Design

  • Control Module: Functional design complete

  • Handheld Device

    • Needle Interface 

      • Design Complete

    • Sensor interface -

      • Joystick Functional Prototype printed

    • Complete device

      • CAD Pending, feedback on joystick functional prototype

  • Pressure Sensing: 

    • Rough calibration verified usability of disposable transducer

    • High accuracy transducer ready for final calibration

  • Fabrication

  • Handheld Device

    • Functional joystick section printed, final design to be printed pending feedback

  • Control Box

    • Machining of faceplate pending arrival of buttons for final dimensional verification

  • Software

    • Variable flow rate control complete

    • Volume readout - Complete

    • Pressure readout - Complete, pending design verification tests

    • Menus - Complete

    • Final integration of software pending

  • Syringe Pump

    • Needs hard stop (e.g. Limit Switches)

  • Tests

    • Verification of syringe pump flow rates for different needles

  • Pressure sensing tests with inflatable bladder/fruit etc to compare pressure in a body vs pressure measured by transducer

    • Software test consisting of users holding prompted flow rates and pressures steady

Accomplishments from Previous Week

• Completed all individual code modules, integration of menus and pump control software is last remaining step

• Completed functional design of needle interface for handheld sensor

• Completed user interface menu

• Complete design of connector for disposable pressure transducer

• Completed software analysis and design of tests for software verification

• Acquired high accuracy pressure transducer for final calibration of disposable pressure transducer

• Interfaced pressure transducer with arduino using IC's and applied analog and digital filters to successfully obtain a usable signal with no lag

• Cut final acrylic prototype for control box face-plate for dimensional verification

• Resolved power source issue

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Design and print final design of handheld flow control device - Michael and Rene

  • Complete integration of software - Jamie and Rene

  • Complete analysis and test design for pressure comparison - Rene

    • Run tests - Pako and Michael

  • Final calibration of pressure transducers - Pako

  • Machine final face-plate design - Pako and Michael

  • Finalize Control Box inner layout design (circuit mounts etc.) - Jamie

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Date: 5/13/14, IN PERSON

  • Needle attachment device

    • Needs to be improved for tightness of luer lock fitting

  • Mounting of syringe pump into control box

    • Syringe pump will be embedded int he control box, not stacked

  • Pressure cutoff for system

    • Seen as a very long term goal once intraneural pressure has been studied with the prototype device

  • Tubing: Will be using smaller tubing

    • Sponsor has not been able to provide samples

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Date: 5/13/14, IN PERSON

  • Rigorous testing required

    • Hardware tests arranged with Dr. Beal using simulation training tissue

  • A good test probes the quality of the control software

    • Software test designed and ready for implementation

  • How precisely does one want to control pressure?

    • Question discussed with Dr. Beal and he suggested importance of flow rate control in paralell

  • Imagine final webpage and what plots will be included

    • Action pending

  • Develop a flow chart with algorithm

    • Preliminary flow chart designed for report draft, needs refinement

  • Software

    • Complex logic is bad

    • Pros/Cons of TTL vs. Serial and discrete vs. continuous

    • Command stacking and overload should be investigated

    • Develop software verification test

    • Send an email with what we learned and an analysis of software decisions as well as a software design verification test

      • Complete

  • Small % of patient problems are bad so everything needs to be done to avoid them, importance of FMECA highlighted

    • FMECA has been addressed with Dr. Beal

    • Steps have been succesfully taken in software to reduce complexity

    • Hardware failures and contingencies have been addressed with Dr. Beal

Comments from Other Students in the Class (indicate date  of comments and if via email or in person)

• • Syringe pump noises are annoying (inferred from reactions)

    • Will call company to investigate source of noise and whether anything can be done about it

Risks and Areas of Concern

• Water resistance of device

Resources or Information Required but not Available

• • NA

Schedule

• • Describe upcoming milestones

    • Testing Software (5/20)

    • Finalizing Calibration of Pressure Transducer  (By end of week 8)

    • Fully functional Handheld prototype (By end of week 8)

    • Fabricating complete prototype and prepare system for testing (By Week 9)

    • Cabling finalization (By week 9)

    • Pressure Design Verification Testing (Week 9)

  • Gantt Chart:

    • A little behind on handheld device due to difficulties with custom sensors and dimensions of off-the-shelf-sensors

    • A little behind on calibration of pressure transducer due to delays in obtaining it

    • Last updated: 5/19/14

Budget (list amount spent and amount remaining)

• • Spent: $850.00

  • Remaining: $1650.00

  • MICHAEL

Progress on Report and Webpage

• • Webpage 

    • 1st Draft Complete

    • 2nd Draft in progress

  • Report 

    • 1st Draft Complete

    • 2nd Draft in progress