Week 7

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

• • Tests

    • Ran tests for two carbon fiber heaters on top of each other

      • Sandwiched

      • By itself

    • Ran tests in which silicone samples were on top of two silicone heaters

  • Design

    • Deciding between two or four panels

  • Fabrication

    • Need to order hollow tubing

    • Hopefully begin fabricating mattress frame by this week

Accomplishments from Previous Week

• • Strain gages

    • Contacted people from Vishay

    • Said strain gages will work with our set up

    • Temperature is not a problem

    • Aluminum or copper sheet metal can be the material that it is applied to

  • Completed more tests with heaters

    • Closer to making a decision

    • Silicone rubber heaters seems like our best option

  • Came up with design solutions for mechanical response

    • Linear actuators

    • Stepper motors

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

• • Decide on a heater (Johnson, Daniel)

  • Fabricate mattress frame (Stephanie, Allen)

  • Create mattress mold (Daniel, Allen)

  • Decide on base material (Johnson, Stephanie)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (2/17/2012)

• • If baby is squirming, would like a response

    • Trying to figure out how we can incorporate response

    • Looking into how we can sense baby's movements:

      • Accelerometer

      • Strain gage

  • Structure is wider than what Dr. Kim would like

    • We are going to trim the sides of the mattress frame

  • Likes the idea of panels that are independent of one another

    • Looking into having separate actuators for each panel

      • Linear actuator

      • Stepper motor

  • If we have four zones, we can use rigid sheets of metal

    • Looking into which is better for distributing heat:

      • Copper or aluminum

  • Thinking of sticking with silicone heaters

    • Ran more tests with carbon fiber heating to validate that this is the right direction

  • Create a small mock-up of the mattress

    • Doing some calculations for thickness of silicone

    • Figuring out the right dimensions

Instructor Comments from Last Meeting and Actions Taken to Address these Comments (2/15/2012)

• • Nice progress on mechanical design of structure

  • Does the flapping motion satisfy sponsor?

    • It does not satisfy sponsor

    • Looking into incorporating four panels instead

  • Consider force sensing resistors instead of strain gages

    • http://www.pololu.com/catalog/product/1645

    • Force sensing resistors are not ideal for measuring weight

    • FSR is also not very accurate

    • Strain gages are more accurate

    • Strain gages harder to implement

  • Organization of presentation was confusing

    • Our next presentation will have our components together instead of spread across presentation

  • Thermal analysis not as clear as it could be

    • Going to link items in legend to figures of thermistor placement

Student Comments from Last Presentation and Actions Taken to Address these Comments (2/15/2012)

• • Remember in your final design to "clean up" as many bolts, holes, gaps as possible

    • Looking into minimizing as much as possible for our next prototype

  • Any movement would induce mechanical sounds... would this disrupt the baby?

    • Trying to figure out what is the quietest actuator we can use

  • Could you use memory foam as your mattress or does it need to be stiffer?

    • Already looked into memory foam

    • It melted when in contact with the silicone heater

  • The silicone feels very human like!

    • Will pursue Rebound further

  • Can you stack the heaters?

    • Ran a test in which the carbon fiber heaters were stacked on one another

Risks and Areas of Concern

• • Sponsor has new functional requirements

  • How much can we get done in about two weeks?

  • Should we further pursue linear actuators or stepper motors?

  • Can we remove a middle supporting piece and have the motors/actuators support all the weight?

Resources or Information Required but not Available

• • What should we have accomplished by Week 9?

  • What is grading more based on?

  • Should we worry about not meeting the sponsor's new functional requirements?

Schedule

• • Describe upcoming milestone

    • Complete testing of sensors and incorporate it into designs

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• • No new purchases

  • Remaining Budget = $925.53

Progress on Report and Webpage

• • Added Week 7 Report

  • Adding in outline of our progress since last draft