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Published byLetitia Porter Modified over 9 years ago
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Kian Hui Wong Chia Siong Goh Wan Qi Choo Jun Jun Peh Presenter: Kian Hui Wong
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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
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Microcontroller (PIC18F64K22) Switching Regulators(LM2675-5,LM2675-3.3) LED driver(AS1116)
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High complexity (64 pin, 8 bit) Controls LCD, buttons input, audio, LED drivers, accelerometer. λ p =(C 1 π T +C2π E )πQπL =(0.14*0.98+.032*4)10*1 =2.652 Failures/10 6 Hours MTTF=10 6 /λ p =377074 hours≈43 years
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Parameter nameDescription ValueComments C1C1 Die complexity0.148-bit microprocessor πTπT Temperature coefficient 0.98Worst case 18mA,V DD =3.3V,F OSC =64MHz, 85°C C2C2 Package Failure Rate 0.03264pins, non hermetic SMT leaded πEπE Environmental constant 4.0Ground, Mobile, handheld equipment πQπQ Quality factor10.0Other Commercial or Unknown Screening Levels πLπL Learning factor1.0In production for 3 years, >2yrs
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Possible high temperature 15V unregulated input 3.3V, 1A max regulated output λ p =(C 1 π T +C 2 π E )π Q π L =(0.02*2.8+0.0034*4)10*1 =0.696 Failures/10 6 Hours MTTF=10 6 /λ p =1436782 hours≈164 years
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Parameter nameDescription ValueComments C1C1 Die complexity0.02Estimated 101-300 transistors MOS (Linear) πTπT Temperature coefficient 2.8-40°C< Junction Temperature<125°C, assume <70°C C2C2 Package Failure Rate 0.00348pins, non hermetic SMT leaded πEπE Environmental constant 4.0Ground, Mobile, handheld equipment πQπQ Quality factor10.0Other Commercial or Unknown Screening Levels πLπL Learning factor1.0In production more than 2 years
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Possible high temperature 3.3V, 335mA typical when all LEDs are lighted λ p =(C 1 π T +C2π E )π Q π L =(0.4*0.6+.011*4)10*1 =2.84 Failures/10 6 Hours MTTF=10 6 /λ p =352113 hours≈40 years
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Parameter nameDescription ValueComments C1C1 Die complexity0.40Estimated 1001 - 3000 transistors MOS (Digital) πTπT Temperature coefficient 0.6-40°C< Junction Temperature<125°C, assume <70°C C2C2 Package Failure Rate 0.01124pins, non hermetic SMT leaded πEπE Environmental constant 4.0Ground, Mobile, handheld equipment πQπQ Quality factor10.0Other Commercial or Unknown Screening Levels πLπL Learning factor1.0In production more than 2 years
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High- Possibility of injury to user Medium-Device not working, not repairable Low- Majority of device still working and can be repaired easily
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Failure modePossible causesEffectDetection methodCriticality 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
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Failure modePossible causesEffectDetection methodCriticality 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
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