P17005: Assistive Tablet Case

Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase



Prototyping, Engineering Analysis, Simulation

Iterative activities to demonstrate feasibility, including assumptions you made in your analyses or simulations. Have you completed sufficient analysis to ensure that your design will satisfy requirements? Have you included all usage scenarios in your modeling?

Feasibility: Prototyping, Analysis, Simulation


  1. Confirm that the selected concepts can deliver functionality defined by the System Architecture.
  2. Define the optimal values of the most sensitive design parameters.
  3. Support the evaluation of your team's concepts with quantitative information.
  4. Make decisions about design drivers.

Initial feasibility analysis has been completed by cutting foam mock-ups of a scaled-up model of an iPad. The forms were used to determine strap placement. The iPad was scaled up to a size representative of a four-year-old using a standard iPad so that we, as adults, could get a sense of how large the tablet would be on a child. This revealed issues with our previous ideas for strap attachment, since we had not realized how small a child would be and how inconvenient the straps would be for the user.

This feasibility analysis helped us develop the current concept that we will be further developing moving forward.

Foam Mock-up

Foam Mock-up

Testing Strap Location

Testing Strap Location

Inputs and Source

  1. Engineering Requirements
  2. Concept Selection
  3. Results of preliminary prototyping, analysis, and simulation

Outputs and Destination

  1. A list of Design Parameters, Quantified Targets, and acceptable tolerances
  2. Sensitivity analysis
  3. Refined concept Selection
  4. Drawings, Schematics, Flow Charts, etc.

Drawings, Schematics, Flow Charts, Simulations

Due to set-backs in Phase 2, the team has not gotten to drawings yet. Instructions will be left here for reference when the team does get to this stage. See System Design for the System Architecture.


Define instructions that will enable fabrication of the elements required to build and operate the entire system.
  1. Define all geometries of interfaced subsystems
  2. Define detailed fabrication instructions for all unique parts.
  3. Call out all purchased parts
  4. Develop a software design that reflects operating flow charts and timing diagrams
  5. Adhere to all required design standards.
  6. Considering the purpose, the team should anticipate potential failure modes associated with construction and use of this document.

Input and Source

  1. Selected Concepts
  2. Feasibility Models
  3. System design and interface definitions

Output and Destination

  1. Complete hierarchy of design files from system level down to components
  2. Parts list
  3. Software design that specifies coding requirements
  4. Test plans, including expected performance vs. requirement and any applicable test standards (e.g., ASTM)

Bill of Material (BOM)


Define all components to be fabricated or purchased. Define all other purchases to enable completion of the project, including operating supplies

Prototyping supplies:

Product Materials:

Manufacturing Processes:

Test Plans


Demonstrate objectively the degree to which the Engineering Requirements are satisfied

Test plans are still in the development phase. Testing thus-far has consisted of outside feedback to our concept and rough mock-ups for concept development.

Design Simulations


Because testing will involve human subjects, every member of the team is completing an Online Training for Testing with Human Subject, after which paperwork will be submitted to the school's IRB for approval. Only the Preliminary Testing Stage can be completed before the IRB paperwork has been approved.

Will obtain data regarding form and appearance of device, usability, improved function, and user experience


Feedback from multiple professionals in the field

Stage 1 Testing with neuro-typical college students

Test survey positive for “Ease of Use,” “Would you use this again” etc

Stage 2 Testing with college students/ adults on the Spectrum

Test survey positive for “Ease of Use”
Measured improvement from baseline (change in time per word selected)

Stage 3 Testing with children on the Spectrum

Test survey positive for “Liked Using,” “Looks cool,” etc
Number of instances used without prompting
Measured improvement from baseline (change in time per word selected)
Child doesn’t show frustration with device during testing

Inputs and Source

  1. Engineering Requirements
  2. Feasibility Models
  3. Test standards

Outputs and Destination

  1. Report that summarized the degree to which Eng Reqs are satisfied.
  2. Assessment of accuracy of feasibility models.
  3. IRB Submission

Design and Flowcharts

This section should continue to be updated from your systems level design documentation.

Risk Assessment

Risks Added:

RU08: Meltdowns - Secured tablet may pose risk to user
RU09: Tablet is too obtrusive

Requirements relating to risk-

CR12: Child must be able to remove device on own
QR10: Emergency release to remove table from user


RD03: Design not applicable for range of devices

The live Requirements and Risks Chart can be found here

Risk Assessment

Risk Assessment

Design Review Materials

Agenda for PDDR

Presentation for PDDR

Plans for next phase

Key goals:

Detail Concept
Feasibility Analysis on Selected Concept
Develop Part Files
Finish Online Training
Finalize and Submit IRB Paperwork
Prototype to Further Develop Concept
Phase 4 Plans

Phase 4 Plans

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Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Integrated System Build & Test with Customer Demo | Customer Handoff & Final Project Documentation