Team # 10 Milestone # 3 System-Level Design Review Faculty
Advisor/Reviewers: Dr. Michael Frank Dr. Bing Kwan Dr. Rajendra
Arora Team Members: Monica Pereira Monique Peregrina Liang Liufu
Ifedayo Ogundana Sponsored by: Albert Daci
Slide 2
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. 2 Monica
Pereira
Slide 3
3
Slide 4
Front View Internal View 4 Monica Pereira
Slide 5
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. DescriptionComponent
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 5 Monica Pereira
Slide 6
The following components have remained the same:
ItemSpecifications Nominal Capacity 1000 mAh Nominal Voltage3.7V
Standard Discharge Current 0.2A Max Discharge Current 2.0 A Cell
Voltage3.7-3.9 V WeightApprox.: 20g 6 Monica Pereira
Slide 7
ParameterValue Regulated output voltage4.20 V Temperature
range-40C to 85C 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. 7 Monica Pereira
Slide 8
Specifications Specifications Type: 555 type, Timer/Oscillator
(Single) Supply Voltage: 2 V ~ 18 V Current: 60A Operating
Temperature: 0C to 70C Max Frequency: 1 MHz 8 Monica Pereira
Slide 9
ColorBlack Cure Cycle24 h Dielectric Strength19.36 kV/mL Pot
Life60 minutes Reasons it was selected: Excellent electrical
insulation properties Good storage stability Supports high
temperatures 9 Monica Pereira
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 Monique Peregrina
Slide 24
Slide 25
Slide 26
FULL CIRCUIT SIMULATION ON BLINK STATE 26 Monique
Peregrina
Slide 27
Slide 28
Battery Life Decreased Probability: Moderate Consequence:
Moderate Strategy El Panel Not Bright Enough Probability: Low
Consequence: Severe Strategy Timing IC Does Not Supply Enough Power
Probability: Low Consequence: Moderate Strategy 28 Monique
Peregrina Disconnected Wires Probability: Moderate Consequence:
Devastating Strategy Moisture near Electronics Probability: Very
High Consequence: Catastrophic Strategy Overheating Probability:
Moderate Consequence: Moderate Strategy
Slide 29
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 29 Ifedayo
Ogundana
Slide 30
More components may be needed Probability moderate Consequence
minor Strategy 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- low Consequence - 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. 30 Ifedayo Ogundana
EL Cap Budget Updated Per-Unit Budget 33 Ifedayo Ogundana
Slide 34
CURRENT EL CAP REPLICATION BUDGET (CUSTOM INVERTER) 34 Ifedayo
Ogundana
Slide 35
35 Monica Pereira
Slide 36
36 Monica Pereira
Slide 37
EXTRA SLIDES FOR REFERENCE 37
Slide 38
38 ItemTest MethodsPerformance Over charge At 205C 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 dischargeAt 205C discharge battery with 0.2A
continuously 12.5h.No explosion or fire Short-circuitAt 205C
connect batteries anode and cathode by wire which impedance less
than 50m, 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
510 degrees per minute to a temperature of 130degrees and remain
inside the oven 60 minutes. No explosion or fire
Slide 39
39 Cautions of charge & discharge Charge Charging 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 mode Charging current should be lower than (or
equal to ) 1A Charging voltage must be lower than 4.25V Discharge
Discharging current must be lower than (or equal to )2A Discharging
voltage must not be lower than 2.75V. Over-discharge It 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.
Slide 40
40 Supply Current - Current in mA/cm2 versus supply voltage: As
the supply current is increased for the EL panel, the supply
voltage also increases. Figure 17 Supply Voltage vs Brightness
Slide 41
41 Brightness Vs Time with 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
Temperature Brightness 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.
Slide 42
42 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.