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Tone Matrix Music Box
Kian Hui WongChia Siong GohWan Qi ChooJun Jun Peh
Presenter: Kian Hui Wong
Project Overview
An 8x8 grid-based music synthesizer made with a button pad at the top and some LEDs at the bottom
Produces sound and emits light (LED) when user touches the buttons
3 music playing modes:
• Sweep mode
• Gravity mode
• Memory mode
Several different types of sound:
• Guitar, Piano, and Drum beats
Components Chosen for Analysis
Microcontroller (PIC18F64K22) Switching Regulators(LM2675-5,LM2675-3.3) LED driver(AS1116)
Microcontroller (PIC18F64K22)
High complexity (64 pin, 8 bit) Controls LCD, buttons input, audio, LED
drivers, accelerometer. λp =(C1πT+C2πE)πQπL
=(0.14*0.98+.032*4)10*1=2.652 Failures/106Hours
MTTF =106/λp
=377074 hours≈43 years
Microcontroller (PIC18F64K22)
Parameter name Description
Value Comments
C1 Die complexity 0.14 8-bit microprocessor
πT Temperature coefficient
0.98 Worst case 18mA,VDD=3.3V,FOSC=64MHz, 85°C
C2 Package Failure Rate
0.032 64pins, non hermetic SMT leaded
πE Environmental constant
4.0 Ground, Mobile, handheld equipment
πQ Quality factor 10.0 Other Commercial or Unknown Screening Levels
πL Learning factor 1.0 In production for 3 years, >2yrs
Switching Regulator(LM2675)
Possible high temperature 15V unregulated input 3.3V, 1Amax regulated output λp =(C1πT+C2πE)πQπL
=(0.02*2.8+0.0034*4)10*1=0.696 Failures/106Hours
MTTF =106/λp
=1436782 hours≈164 years
Switching Regulator(LM2675)
Parameter name Description
Value Comments
C1 Die complexity 0.02 Estimated 101-300 transistors MOS (Linear)
πT Temperature coefficient
2.8 -40°C< Junction Temperature<125°C, assume <70°C
C2 Package Failure Rate
0.0034 8pins, non hermetic SMT leaded
πE Environmental constant
4.0 Ground, Mobile, handheld equipment
πQ Quality factor 10.0 Other Commercial or Unknown Screening Levels
πL Learning factor 1.0 In production more than 2 years
LED driver (AS1116)
Possible high temperature 3.3V, 335mAtypical when all LEDs are lighted λp =(C1πT+C2πE)πQπL
=(0.4*0.6+.011*4)10*1=2.84 Failures/106Hours
MTTF =106/λp
=352113 hours≈40 years
LED Driver (AS1116)
Parameter name Description
Value Comments
C1 Die complexity 0.40 Estimated 1001 - 3000 transistors MOS (Digital)
πT Temperature coefficient
0.6 -40°C< Junction Temperature<125°C, assume <70°C
C2 Package Failure Rate
0.011 24pins, non hermetic SMT leaded
πE Environmental constant
4.0 Ground, Mobile, handheld equipment
πQ Quality factor 10.0 Other Commercial or Unknown Screening Levels
πL Learning factor 1.0 In production more than 2 years
Definition of Criticality Level
High- Possibility of injury to userMedium-Device not working, not
repairableLow- Majority of device still working
and can be repaired easily
FMCEA chartFailure mode Possible causes Effect Detection method Criticality
Power supply unregulated
Failure of LM2675 switching regulator, poor soldering, bypass capacitor failure
Possible damage to most components due to overheat
Temperature raises beyond working range,Smell of burning, Probe PCB power traces
High
Battery deep-discharged
Battery fuel gauge failure, Microcontroller USART failure
Explosion, fire, shorten battery lifecycle
Battery gets overheated
High
Microcontroller not working
Bypass capacitors shorted or not connected, bad soldering
All subsystems are no longer able to communicate with each other
Observation, Program(if possible) and toggle every IO pins
Low-Medium
FMCEA chartFailure mode Possible causes Effect Detection method Criticality
LEDs are not lighted up
LED drivers failure, current limiting resistor shorted
LEDs not lighted up, LEDs will be burnt
Observation (visual) Low
Speaker is not outputting sound
DAC IC failure,Amplifier IC failure
Speaker and audio jack fail to work
Observation (hearing), Probe for audio output, compare between MIDI output and DAC output
Low
Button pad not working
Button pad conducting pad is worn out, Microcontroller failure, Poor soldering, Buttons diode failure
Buttons are not detected when pressed
Observation (visual), check connection of button pads
Low
