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External Enclosure

External Enclosure. External Enclosure. Needs The external package should be lightweight/ robust/ water resistant The devices should be competitive with current devices The device should fit into a small pouch and be comfortable for user and be comfortable for the user

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External Enclosure

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  1. External Enclosure

  2. External Enclosure • Needs • The external package should be lightweight/ robust/ water resistant • The devices should be competitive with current devices • The device should fit into a small pouch and be comfortable for user and be comfortable for the user • The external package should resist minor splashing • The device should survive a fall from the hip • Risks • Housing for the electronics is too heavy/large/uncomfortable • Water can enter the external package and harm the electronics • The housing fails before the electronic components in drop tests • The electronic components can not survive multiple drop tests

  3. Concept Generation- Materials/Manufacturing Process

  4. Rapid Prototyping • Machinable • Material can be drilled and tapped (carefully) • Accepts CAD drawings • Complex geometries can be created easily • Ideal for proposed ergonomic shape • Builds with support layer • Models can be built with working/moving hinges without having to worry about pins • Capable of building thin geometries • ABSplus • Industrial thermoplastic • Lightweight - Specific gravity of 1.04 • Porous • Does not address water resistant need http://www.dimensionprinting.com/

  5. ABS Plastic • Important Notes • Relatively high tensile strength • Glass Transition well above body temperature • Specific Gravity indicates lightweight material

  6. Feasibility- Water Ingress Test • Need: The external package should resist minor splashing • Specification: Water Ingress Tests • Once model is constructed, (user interface, connectors sealed, lid in place) exclude internal electronics and perform test • Monitor flow rate (length of time and volume) of water • Asses the quality to which water is prevented from entering case by examining water soluble paper • Risk: Water can enter the external package and harm the electronics • Preventative measures: • Spray on Rubber Coating or adhesive • O-rings around each screw well and around the lid • Loctite at connectors • Preliminary Tests without protective coating show no traceable water ingress Loctite Spray on Rubberized Coating

  7. Feasibility- Robustness Testing • Need: The device should survive a fall from the hip • Specification: Drop Test • Drop external housing 3 times from 1.5 m, device should remain fully intact • Specify and build internal electrical components • Identify the “most vulnerable” electrical component(s) which may be susceptible to breaking upon a drop • Mimic those components using comparable (but inexpensive and replaceable) electrical components, solder on point to point soldering board • Goal • Show the housing will not fail • Show electronics package will not fail, when subjected to multiple drop tests • Risks • The housing fails before the electronic components in drop tests (proved unlikely with prototype enclosure) • The electronic components can not survive multiple drop tests • Preventative Measures • Eliminate snap hinges from housing (tested and failed) • Test the housing first • Design a compact electronics package

  8. Feasibility- Heat Dissipation of Internal Components • 130°C is absolute maximum for chip junction temperature in order to function properly • Goal- comfort for the user • Assumed steady state, heat only dissipated through 3 external surfaces • Maximum heat dissipation ~25W • Actual heat dissipation ~5W Tout Tin h Q t, k

  9. Prototype Enclosure • Survived drop test • Water resistant • Plastic is machinable • Drilled, tapped, milled • Helicoilsshould be used to tap holes • Constant opening and screwing and unscrewing of lid will result in stripped threads • Approximate wall thickness (6mm) • Distance between center of holes and wall needs to be increased • Some cracking occued • Latches are not feasible

  10. User Interface From Pump To Battery BATTERY MENU + Speed Battery Life Fault Indication To Battery To/From Computer ERROR OK - Components: Indication of battery life (3x LED) Indication of Fault (LED and Buzzer) Indication of levitation (LED) Display Increase/Decrease Speed (2x Button) Menu (Button) Connectors: 26- pin LEMO connector USB connector Battery Terminals (x2) OK: Indication of levitation ERROR: No Levitation, connection errors

  11. User Interface- Components LED Backlit display with waterproof bezel and o-ring G/R/Y LEDs with O-ring and waterproof bezel Waterproof buttons with O-ring

  12. User Interface- Connectors Current Model: Part # EGG 2K 326 CLL Proposed: Part # EEG 2K 326 CLV Pin Layout

  13. User Interface- IP Codes

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