Week 4

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

• • Design

    • Began designing the base structure of Prototype #1

    • Began designing Prototype #2

    • Spoke with Isiah as to the plausibility of our design for Prototype #1

    • Design a mold for our 18"x18" mattress

  • Fabrication

    • Created the folding structure of Prototype #1 out of PVC pipe

    • Spoke with Isiah on ways to fabricate Prototype #1

      • Gave ideas as to how to create an aluminum version of Prototype #1

  • Tests

    • Tested samples that we created:

      • Rice

      • Sand

      • Glass Tile

      • Glass Marble

    • Tested the shim stock

Accomplishments from Previous Week

• • Created molds for curing silicone samples

  • Created portions of Prototype #1 with PVC pipe

  • Able to control PWM of the heater through the Arduino

  • Created multiple silicone samples and tested them

    • Sand

    • Rice

    • Glass tile

    • Glass Marble

  • Created a CAD of the 18"x18" mattress mold

  • Modified/improved upon CAD of the base for Prototype #1

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

• • Finish first draft of Report (Johnson, Daniel, Allen, Stephanie)

  • Finish CAD of Prototype #2 (Daniel, Allen)

  • Have parts ordered for Prototype #1 (Stephanie, Johnson)

  • Look into printed circuit board (Daniel, Allen)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (1/25/2012)

• • Happy with the Ecoflex

    • Looking into purchasing a gallon of Ecoflex

  • Softness and temperature matters the most

    • Have different silicone mixes we can test out for softness

    • Running various temperature tests

  • Test: sleep on the silicone; does it get sweaty/disgusting?

    • Smooth on reps said that people actually use silicone for special needs beds

    • Looking into getting more silicone mixture

  • Get the reservoir to the same temperature and see how both behave

    • Re-did our heating and cooling tests

  • Can you embed stuff within silicone?

    • Called Smooth On; They said yes

    • Did our own embedding samples

  • Silicone by itself would not be an ideal reservoir

    • Created different samples with various reservoirs embedded

Instructor Comments from Last Meeting and Actions Taken to Address these Comments (1/25/2012)

• • Explain why silicone with glass beads was built

    • Glass beads added to silicone for its high specific heat.  

  • Explain the desire for soft material with high specific heat (and will not leak)

    • soft material is needed to simulate human tissue while also be able to adjust to the position of the base structure

  • For product information, in addition to Steve Roberts, look to the supplier and published literature

    • Information on some products in question was found using the CES and others through testing, such as rice.

  • For the Presentation

    • Explain reasons for limited contact for premature babies with parents

    • Have a seperate slide for each design decision

    • List requirements and alternatives considered for design decisions

    • Write out an explanation for "Adequate vs. Best Choice" 

    • Graphs

      • Show electrical circuit

      • Compare results to published specific heat values

      • Use consistent colors from slide to slide or show both graphs on the same figure

    • Add labels to the Design slide

    • Calculations

      • show cross section of silicone pad

      • List fundamental assumptions and equations

      • Include time into analysis

Peer Comments from Last Presentation and Actions Taken to Address these Comments (1/25/2012)

• • Look at a copper mesh to address your uniform heating concerns

    • Acquired some shim stock to test how well the whole thing heats up

  • Bury pressure sensors into mattress

    • Looking into how well we can place things in the silicone

    • Layering vs embedding

  • Fail safe device in case it overheats

    • Looking into how well we can control the Arduino in case such a thing happens

  • Sand may spill and be difficult to clean; silicone + glass seems better for this

    • Testing sand to see if we can eliminate it as a potential reservoir

  • Has there been any child development research done on "what infants do?"

    • In the process of getting "Happiest Baby on the Block"

      • Goes over how to calm babies down

  • Silicone has too much friction,might need another layer between baby and silicone

    • Looking into mixing various grades of silicone

    • Trying different mixes and making layers of different grades

  • Why not mold sand into the silicone similar to the glass beads?

    • Made a sand+silicone hybrid sample

Risks and Areas of Concern

• • How do we provide uniform heating?

    • What material can we place on top of the heaters?

  • How do we keep the hinge from buckling/collapsing upon itself

Resources or Information Required but not Available

• • Thermography

    • Infrared goggles/camera

    • To look for hot zones

    • More efficient than thermistors

Schedule

• Describe upcoming milestone

  • • Week 5: Have functioning prototype for testing

• Update Gantt chart.

Budget (list amount spent and amount remaining)

• • Digi-key

    • Resistors

      • 1 kOhm

      • 8.66 kOhm

      • 20 kOhm

    • Transistors

  • PVC Pipe

  • TOTAL for the Week: 46.64

  • Remaining Budget = $1259.13 - 46.64 = 1212.49

Progress on Report and Webpage

• Report guidelines have yet to be posted on class website

• Added Weekly Report #4