Electroluminescent Logo Cap Project
Team # 10Milestone # 3 –System-Level Design Review
Faculty Advisor/Reviewers:Dr. Michael FrankDr. Bing KwanDr. Rajendra Arora
Team Members:Monica PereiraMonique PeregrinaLiang LiufuIfedayo Ogundana
Sponsored by:
Albert Daci
Monica Pereira
2Introduction/Overview of the Project
• The purpose of this project is to design an original cap that implements electroluminescent technology. This cap will consist of a panel with flashing capabilities and with a hidden internal circuit.
• Each cap will implement a switch with three states (turn on, flash, turn off) and be provided with an internal circuit with water resistant capabilities. In addition, the cap will come with a micro-USB charger hidden underneath the bill of the cap.
3
ADDITIONAL CONCEPT GENERATION & SELECTION
Monica Pereira
4Prototype ConceptFront View Internal View
Monica Pereira
5Overall Design Components
• Fitted baseball cap• LiPo rechargeable
battery • Battery charger• 10cm x 10cm EL panel• 3V DC battery inverter• IC chip• Liquid Encapsulating
epoxy resin
Reference No.
Description Component fulfilling this requirement
REQN-001
The design must be able to light on, blink and turn of.
Timing IC
REQF-002 Use slim batteries that maximize the prototype efficiency
Li-Po rechargeable battery & battery charger
REQN-004
REQN-006
Components will be water resistant Design will withstand common wear and tear.
Epoxy resin encapsulating material
CAP-001
REQF-004
Panel must be able to turn on continuously, blink and turn off. A miniature button switch should be implemented in the bill to turn on/flash/turn off the EL logo.
Blinking will be fulfilled through the timing IC The three operating modes will be operated through the single pole, triple-throw switch
Monica Pereira
6
Component selectionThe following components have remained the same:
PRT-00339 Lithium Polymer Battery
Item SpecificationsNominal Capacity
1000 mAh
Nominal Voltage
3.7V
Standard Discharge Current
0.2A
Max Discharge Current
2.0 A
Cell Voltage 3.7-3.9 VWeight Approx.: 20g
Monica Pereira
7
Parameter Value
Regulated output voltage
4.20 V
Temperature range -40ºC to 85ºC
PRT-00339 Lithium Polymer micro-USB Battery Charger
The LiPo Charger Basic uses a Microchip MCP73831T-2ACI/OT charge management controller to charge 3.7V Li-Po batteries at a rate of 500mA per hour.The board incorporates a charging circuit, status LED, connector for your battery (JST type), and USB connector. A small mounting hole allows this charger to be embedded into a project easily.
Monica Pereira
8
Intersil LM555 timer IC• Specifications• Type: 555 type, Timer/Oscillator
(Single) • Supply Voltage: 2 V ~ 18 V• Current: 60µA• Operating Temperature: 0ºC to
70ºC • Max Frequency: 1 MHz
Monica Pereira
9Waterproofing/Insulating component Selection
Liquid Encapsulating Epoxy Resin
Color BlackCure Cycle 24 hDielectric Strength 19.36 kV/mLPot Life 60 minutes
Reasons it was selected:• Excellent electrical insulation
properties • Good storage stability • Supports high temperatures
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Altered Selections
Monica Pereira
11
Specifications EL panelGlow size 10cm X 10cm
(3.95" x 3.95")Panel lifetime Greater than
25000 hoursOperating voltage
60-250V AC
Operating frequency
50-5000 Hz
Current Draw 0.14mA/cm2 (max) @ 110V / 400Hz
Initial Brightness 75 cd/m2
Operating Temperature
-50ᵒ C / 65ᵒ C
Panel Capacitance
45nF
EL Panels EL Panels from Surelight.com (Previous vendor was Adafruit)
Monica Pereira
12Battery Inverter
Weight 2.2g
Frequency 2500Hz
Power Supply Required
3V or 1.5V DC
3V ELI-IMC Battery Inverter
Previous OptionIn progress Approach:
Design our own inverter instead
13
SYSTEM DESIGN
Liang Liufu
14
Top Level Block Diagram
Liang Liufu
15
R1
150Ω
L1
3.518H
PanelC45nF
PanelR200Ω
Wien_Bridge_Oscillator
LM741CH
3
2
4
7
6
51
R3
398Ω
R4
490Ω
R5
398Ω
R6
1kΩ
C1
1µF
C3
1µF
V3
-3.7 V
555_Timing_IC
LM555CMGND
DIS
OUTRST
VCC
THR
CON
TRI
C40.1µF
RA1.0MΩ
RB220kΩ
CT1µF
C50.1µF
Switch
Key = Space Battery3.7 V
Timing_IC_Circuit
Oscillator_Circuit
Resonant_Circuit
Switch_Circuit
13
C21µF
Overall System Design
Liang Liufu
16
Requirements:• Input uses 3.7VDC• Output 110VAC• Output Current: >14mA• Output Frequency: 400Hz
Inverter Design
Liang Liufu
17
Wien-Bridge Oscillator Requirements• 3.7V input• 400Hz output• 20mA output
V1
3.7 V U1
LM741CH
3
2
4
7
6
51
R1
398Ω
R2
490Ω
R3
398Ω
R4
1kΩ
C1
1µF
C2
1µF
V2
-3.7 V
Vout
Inverter Sub-circuit: Oscillator
Liang Liufu
18
Output:•4.7Vp-p•27.6mAp-p•395Hz
Oscillator Simulation
Liang Liufu
19
Requirements:• Amplify oscillator signal to
achieve 110VAC• Maintain 400Hz• Output current of 14mAp-p
Inverter Sub-circuit: Resonant Circuit
Liang Liufu
20
Resonant Circuit Simulation
113VACp-p output12.1mAp-p output400Hz output
Liang Liufu
21
Overall Inverter Circuit
Liang Liufu
22Overall Circuit Simulation
110VACp-p Output14.1mAp-p Output395Hz
• In charge of controlling the blink pattern
• Will allow the logo to flash every second
• Uses a 555 Timing IC Specifications:• Power consumption: 15
mW• Input voltage: 3.7V• Output Voltage: 3.7V• Frequency: 1 Hz
Timing IC Subsystem
Monique Peregrina
555 Timing IC in Astable Mode
Monique Peregrina
Transient Analysis on the Timing IC
Monique Peregrina
26FULL CIRCUIT SIMULATION ON BLINK STATE
Monique Peregrina
RISK ANALYSIS
Monique Peregrina
28
• Battery Life DecreasedProbability: ModerateConsequence: ModerateStrategy
• El Panel Not Bright EnoughProbability: LowConsequence: Severe Strategy
• Timing IC Does Not Supply Enough Power Probability: LowConsequence: Moderate Strategy
Technical Risks
Monique Peregrina
• Disconnected WiresProbability: Moderate Consequence: DevastatingStrategy
• Moisture near Electronics Probability: Very HighConsequence: CatastrophicStrategy
• OverheatingProbability: Moderate Consequence: Moderate Strategy
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• Tasks Assignment • Probability- high; Consequences- moderate• Strategy – Proper communication amongst members.
• Design dependencies• Probability- low; Consequences- moderate; Strategy- to be
set aside for help from advisor• Personal complications
• Probability- very low; Consequences – severe; Strategy – re-planning of task division
• Individual productivity• Probability- high; Consequences – severe; Strategy-
constant evaluation of individual progress
Schedule Risks
Ifedayo Ogundana
Ifedayo Ogundana
30
• More components may be neededProbability – moderate Consequence – minorStrategy – some funds are reserved
• Damaging the timer IC and/or the inverter Probability – low Consequence – severe Strategy – funds are reserved for purchase of extra major components
• Unaccounted-for-costs Probability- lowConsequence - moderate, Strategy – low price components are purchased and expenses are cut down
• Budget limitations Probability – low Consequence – moderate Strategy – component parts are ordered to together to reduce cost of shipping.
Budget Risks
Ifedayo Ogundana
31Updated BudgetCURRENT EXPENSES (CUSTOM
INVERTER)
Expenses Subtotal = $413.89 → $650.00 - $413.89 = $236.11 (Under budget)
Ifedayo Ogundana
32CURRENT EXPENSES (OFF-THE-SHELF INVERTER)
For off-the-shelf inverter:Expenses Subtotal = $446.34 → $650.00 - $446.34 = $203.66 (Under budget)
Ifedayo Ogundana
33
EL Cap BudgetUpdated Per-Unit Budget
Ifedayo Ogundana
34CURRENT EL CAP REPLICATION BUDGET (CUSTOM INVERTER)
35Updated Schedule
Monica Pereira
36
Thank You!Questions ?
Monica Pereira
37
EXTRA SLIDES FOR REFERENCE
38
Item Test Methods Performance
Over charge
At 20±5°C charging batteries with constant current 3A to voltage 4.8V, then with constant voltage 4.8V till current decline to 0. Stop test until batteries temperature is 10 degrees lower than max temperature.
No explosion or fire
Over discharge At 20±5°C discharge battery with 0.2A continuously 12.5h. No explosion or fire
Short-circuit At 20±5°C connect batteries’ anode and cathode by wire which impedance less than 50mΩ, keep 6 h
No explosion or fire
Thermal shock
Put the battery in the oven. The temperature of the oven is to be raised at 5±10 degrees per minute to a temperature of 130degrees and remain inside the oven 60 minutes.
No explosion or fire
Safety TestTest conditions: The following tests must be measured at flowing air and safety protection conditions. All batteries must standard charge and lay 24h.
Li-Po Battery Performance
39
Cautions of charge & dischargeChargeCharging current should be lower than values that recommend below. Higher current and voltage charging may cause damage to cell electrical, mechanical, safety performance and could lead heat generation or leakage.Batteries charger should charging with constant current and constant voltage modeCharging current should be lower than (or equal to ) 1ACharging voltage must be lower than 4.25VDischargeDischarging current must be lower than (or equal to )2ADischarging voltage must not be lower than 2.75V.Over-dischargeIt should be noted that the cell would be at an over-discharge state by its self-discharge. In order to prevent over-discharge, the cell shall be charged periodically to keeping voltage between 3.6-3.9V.
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Supply Current - Current in mA/cm2 versus supply voltage:
As the supply current is increased for the EL panel, the supply voltage also increases.
EL Panel Specs
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Brightness Vs Timewith time.
Unlike most other lighting which can critically fail, EL Panel brightness decreases with time.
The following factors have an impact on lifetime:• Higher Voltage• Higher Frequency• DC Supply• High Ambient Humidity• High Ambient TemperatureBrightness can be increased by using a higher voltage or higher frequency.Higher voltage slightly decreases life time, but is preferred if higher supply current can be accepted.
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EL Panels emit light from 50VAC and increase in brightness with higher voltage up to 200VAC. The frequency should be over 50Hz. Brightness increases with higher frequency up to 1000Hz. However, it is recommended that frequencies in the range of 400-600Hz and voltages of no greater than 160VAC are used, otherwise the panel life will rapidly deteriorate.
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Timing IC and MOSFET Integration