P13036 NOTIFICATION ALERT

Detailed Design Review

Date: February 15, 2013

Meeting Location: 17-1545

Meeting Time: 3:00 – 5:00 pm

Technical Review Agenda P13036: Notification Alert------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

MembersPatrick Ganson, CE Stephen Moskal, CE Umer Usman, EEElizabeth Phillips, EE Thomas Adcock, ME William Johnson, MEMeeting Purpose:

1. Review Traceability Matrix/Risk Assessment2. Updates on progress for CE and MEs

Materials to be Reviewed: 1. Customer Needs/Specifications2. Risk Assessment3. Case/Internal Structure Design4. Thermal Analysis5. Force Analysis6. Mobile Application User Interface7. Software UML Diagram8. LCD Screen Notification Images9. Bill of Materials10. Questions/Concerns

Technical Review Agenda – EE’s P13036: Notification Alert------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

MembersPatrick Ganson, CE Stephen Moskal, CE Umer Usman, EEElizabeth Phillips, EE Thomas Adcock, ME William Johnson, MEMeeting Purpose:

1. Provide overview of project history and design methodology2. Review EE Schematics and Layout Diagram

Materials to be Reviewed: 1. Functional Decomposition2. Customer Needs/Specifications3. Risk Assessment4. Case/Internal Structure Design5. EE Schematics and Diagrams6. Bluetooth Module Information7. Bill of Materials

MEETING TIMELINE – ME’s and CE’s

Meeting TimelineStart Time Topic of Review

3:00 Introduction

3:05 Customer Needs/Specifications, Risk Assessment

3:15 Case/Internal Structure Design

3:20 Thermal Analysis

3:25 Force Analysis

3:30 Mobile Application User Interface

3:35 Software UML Diagram

3:40 LCD Screen Notification Images

3:45 Bill of Materials

4:00 Questions, Comments, Concerns

MEETING TIMELINE – EE’s

Meeting Timeline – EE’sStart Time Topic of Review

4:00 Introduction

4:03 Customer Needs/Specifications, Risk Assessment

4:10 Case/Internal Structure Design Update

4:15 Electrical Block Diagram

4:20 Battery Testing Results

4:25 Charging/Regulation/Indication

4:30 Switch Control Circuit

4:35 Circuit Layout Schematic

4:40 Electrical Simulation Schematic

4:45 Bluetooth Module Information

4:50 Bill of Materials

4:55 Questions, Comments, Concerns

TRACEABILITY MATRIX

P13036 - Notification Alert

S1 S2 S3 S4 S5 S6 S7 S8 S9

Weight Size Indication System

Activation System (Light source, Bed

Shaker)

Variable flashing

frequencies

Variable shaking

frequencies

Compatible charger plugs for Light

source and Bed Shaker

Robust Rechargeable

Batteries

LowCost

CN1 Lightweight for travel and easy to carry X CN2 Small for travel and easy to carry X CN3 Power Indicator RemovedCN4 Alarm Indicator X CN5 Bluetooth Indicator X

CN6 Plug in bed shaker and/or light to activate via alarm X

CN7 Blinking High Intensity LEDs X CN8 Variable blinking patterns for LEDs X CN9 Vary shaking frequency X CN1

0 Quality product

CN11 Rechargeable batteries. X X X

CN12 External power connection/charge batteries X

CN13 8-12 hour battery life for travel X

CN14 Deliver a functional prototype

CN15 Keep the product inexpensive ($100) X

CN16 Stand alone alarm when PDA is not synced

CN17 Quality/attractive shell/external design X X

CN18 Long Lifetime (roughly 10 years)

CN19 User-friendly Product

CN20 LCD Display to show clock/alarm X X X

CN21

Output will deactivate after a reasonable amount of time X

CN22 Long range/reliable Bluetooth device

CN23 Alarm turn off switch when activated

CN24 Switch to disable alarm anytime

TRACEABILITY MATRIX (CONTD.)

P13036 - Notification Alert

S10 S11 S12 S13 S14 S15 S16 S17 S18 S19Alarm

Activation (self-

sustaining clock)

Lifetime of

Product

Drop Standard

Housing Material Selection

Shock Resistance

Distance that

Bluetooth works

Percent Reliability

Alarm self-deactivate/self-

reactivate

Time it takes to deactivate

system

Device temperature

CN1 Lightweight for travel and easy to carry X

CN2 Small for travel and easy to carry CN3 Power Indicator RemovedCN4 Alarm Indicator

CN5 Bluetooth Indicator

CN6 Plug in bed shaker and/or light to activate via alarm

CN7 Blinking High Intensity LEDs CN8 Variable blinking patterns for LEDs CN9 Vary shaking frequency

CN10 Quality product X

CN11 Rechargeable batteries.

CN12 External power connection/charge batteries

CN13 8-12 hour battery life for travel

CN14 Deliver a functional prototype X

CN15 Keep the product inexpensive ($100)

CN16 Stand alone alarm when PDA is not synced X

CN17 Quality/attractive shell/external design X X X X

CN18 Long Lifetime (roughly 10 years) X

CN19 User-friendly Product X X CN20 LCD Display to show clock/alarm X

CN21Output will deactivate after a reasonable

amount of time

CN22 Long range/reliable Bluetooth device X X

CN23 Alarm turn off switch when activated X X

CN24 Switch to disable alarm anytime X X

RISK ASSESSMENT

CASE / INTERNAL STRUCTURE DESIGN

Dimensions: 132 x 132 x 46 mm ≈ 5.2 x 5.2 x 1.9 in

Volume:801504 mm3 ≈ 48.9 in3

The highlighted area are possible locations for the alert LEDs which will be decided once the location of the PCB is determined.

CASE / INTERNAL STRUCTURE DESIGN

This is the top view of the case without the top.

CASE / INTERNAL STRUCTURE DESIGN

This is the top view of the case without the top and LCD screen.

The highlighted area shows possible locations for the PCB board in the base of the case. Once a final dimension has been established for the PCB the excess space will designed out for our final design.

CASE / INTERNAL STRUCTURE DESIGN

Front cut view

Side cut view

THERMAL ANALYSIS

THERMAL ANALYSIS

THERMAL ANALYSIS

THERMAL ANALYSIS

THERMAL ANALYSIS

Results:

•From the Raspberry Pi FAQ page, the components on the Raspberry Pi are rated up to 70°C but not below 0°C.•This means the maximum operation temperature under the worst case conditions is estimated to be 58.8°C, near the ideal value of 60°C listed in the specifications. (The example was 40°C ambient, but the internal temperature is 11.2°C above ambient for any ambient temperature)•Most of the temperature difference is due to the convective thermal resistance on the outside of the case, meaning changes in case thickness for structural reasons will not cause serious detriment to the thermal capabilities of the device.•Overall thermal issues are not expected to be a feasibility concern.

FORCE ANALYSIS

Initial Approach

• The initial approach was a simplified model having the case in static loading supporting 20 times the weight of the final device.

Problems with this approach

• Static loading does not accurately capture the dynamic aspects that would most likely cause damage to the case or its contents.

• The impact in the most damaging configurations is not considered.

FORCE ANALYSIS

Alternate Approaches:

• 2D or 3D static analysis at different angles • May require contact elements and several iterations refining the

mesh • Will still not give information regarding the harmful dynamic aspects

of impact • 2D Dynamic analysis

• Will capture some of the dynamic effects needed to properly predict failure

• Will be computationally intensive and is beyond material covered in RIT classes such as Advanced Computational Techniques and Computer Implementation of Finite Elements

• Will not properly capture the stresses at key points like the enclosure corners

• 3D Dynamic analysis • Beyond classes taught at RIT • Speaking with Dr. Boedo of the Mechanical Engineering department,

it was suggested that building and testing prototypes would be more effective than trying to complete this analysis

FORCE ANALYSISConclusions and Comments:

• The micro-controller case printed earlier in the quarter successfully protected the Raspberry Pi from a drop.

• The most reasonable plan at this time it to destructively test prototype enclosures to improve the design.

• Alternately the requirement of impact testing may be dropped due to this being a proof of concept which will differ from the final design.

• The customer specification is listed as 20G. This amplitude of acceleration falls between a high G maneuver in a fighter plane and what causes harm to humans.

• The momentary nature of the impact changes the way in which the case will react.

• For example, while normally over 25G will cause death or serious injury, momentary impact in a survivable car crash can reach 100G. This change in the effect of G forces as they act in the short term makes the steady state analysis not very indicative of the actual outcome.

• A more useful test may be dropping from a specified height because it is more indicative of what is being tested and requires less instrumentation.

MOBILE APPLICATION USER INTERFACE

Main Screen Alarm Screen / DropDown Menu

MOBILE APPLICATION USER INTERFACE

Add Alarm Screen Set Alarms Screen

MOBILE APPLICATION USER INTERFACE

App Settings Screen Bluetooth Devices Screen

SOFTWARE UML DIAGRAM/CODE DESCRIPTIONS

LCD IMAGES (someone give me a better title)

Main Display Screen

Email Notification Screen *LED Activation*

Alarm Screen *LED Activation*

Demonstration following presentation

ELECTRICAL BLOCK DIAGRAM

ELECTRICAL SIMULATION SCHEMATIC

BATTERY LIFE

Simulation used a 10 Ω resistor to represent the Raspberry PI, causing an average current of 500 mA. The 7.4 V Battery was not completely drained before the test was

over due to the 5V regulator being unable to put out the 5V anymore. This is due to the 0.6-0.8 V drop across the MAXIM board and the regulators limitations.

16 ½ hours 10 ½ hours

CHARGING/REGULATION/INDICATION SCHEMATIC

SWITCH CONTROL CIRCUIT

CALCULATIONSLM339

+7

-6

V+3

V-12

OUT1

10k

10k

4.7k

10k

0

VREG5

VBATT8.2-6 V 0

OUTPUT to LEDs

0

0

3.4 V

4.1 - 3 V• From battery testing, when the battery reaches 6.63V, the 5V regulator can no longer keep the output to sustain the RPi. To avoid this problem, created an indicator circuit to warn customers to plug in.• Choose VBATT to 6.8 V which would give a customer about 30 mins before power would go off in the device.LM339 Quad Comparator

• If IN+ > IN- then output is on• If IN- > IN+, then output floats

1) Decided to use a voltage divider on the input of the battery to limit voltage and protect the LM339. Choose to use a 10kΩ voltage divider.

2) In general, VOUT = ½ VIN. To use the LM339, need to use a voltage divider on the input of the 5V to equal 3.4 V. Assume R3 = 10kΩ.

CALCULATIONS

•The MAX1758 Li-Ion battery charger comes with the ability to configure the current to the battery and input current. For our case, 1A battery charging current will be calculated and the input current will kept at the maximum.

MAXIM - MAX1758 Battery Charging Current

Using R4 = 100k Ω and ICHG = 1A

CIRCUIT LAYOUT SCHEMATIC

BLUETOOTH MODULE

After the long discussions, we have chosen to use the BlueGiga WT12 Class 2 Module

Objectives:• Implementation of OPP profile with Android devices• Programming of WT12 using iWrap 5.0• Use of TXD and RXD links for the Raspberry Pi using UART• Design PCB for WT12 with Android implementation• PCB space for ACP once design has been finalized• Support the future team with WT12 use

BILL OF MATERIALS (BOM)

BILL OF MATERIALS (BOM)

THE END!

Questions? Comments?