Team 9 - Scribacious Rabble Safety and Reliability Analysis Mitchell Erdbruegger (presenting) Paul Rosswurm William Hess Ben Kobin

Project Description Adaptation of the board game SCRABBLE® Maintains the traditional physical tile interface... augmented by.. Sensing tile location and value Automatically calculating and displaying scores Maintaining player profiles Validating words in the event of a 'challenge' Exposing game stats over an external interface

PSSCs An ability to sense the presence and identity of a tile placed on the board. An ability to record game specific metrics for a set of player profiles. An ability to use a standard dictionary to allow a player to challenge the validity of the last word played. An ability to display game relevant information to each player and allow one user to input game settings. An ability to communicate game statistics over an external interface.

Block Diagram

Chosen Parts Micro-Controller (PIC24EP256GU810)  λ P = (C 1 * π T + C2 * π E ) * π Q * π L  λ P = ( 0.28 * * 2.0) * 10 * 1.0  λ P = 5.56  MTTF: 20.5 Years Low Drop-Out Linear Regulator (LM1117)  λ p = λ b *π T *π S *π C *π Q *π E  λ p =.0020 * 5.1 * 1.0 * 1.0 * 6.0 * 8.0  λ P =  MTTF: 233 Years

Chosen Parts 8-Bit Shift Register (74HC164D)  λ P = (C 1 * π T + C2 * π E ) * π Q * π L  λ P = ( * * 2.0) * 10 * 1.0  λ P =  MTTF: Years Opto-Isolator (LTV-826S)  λ p = λ b *π T *π Q *π E  λ p = * 6.6 * 2.0 * 8.0  λ P =  MTTF: 63.5 Years Others Considered LCD Driver (Sitronix ST7565P) Capacitive Grid

Criticality Levels Low < Failures No Harm to Users Possibly render product unusable

FMECA Power Supply and LCD Circuits Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection CriticalityRemarks PS1 V Out = 0 Failure of the LM1117, Shorted Decoup Caps No Power to the rest of the system, Entire product useless Observation (Use of voltmeter to check input/output voltage) Low PS2 V Out > 3.3V Failure of the LM1117 Could potentially cause irreparable damage to ICs Observation (Voltmeter on output) Low Possibly fixed with zener diode to protect rest of circuit L1 Output LCD Contr Always 0 LM1117 Failure (PS1), Shorted Decoup Cap, Burned out contr. (Possibly PS2) No backlight on the LCD Observation (Oscilloscope readout) Low L2 No power going to LCDs LM1117 Failure (PS1), Shorted Decoup Cap Nothing can be ouput to LCDs Product rendered essentially useless Observation (Volt meter) Low

Power Supply

FMECA Micro-Controller Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection CriticalityRemarks M1 USB D- and D+ always 0 or 1 Software bug, broken usb module (possibly cause by PS2), Connected USB device pulling low or high Failure to communicate player statistics to PC via USB Observation (Oscilloscope) Low M2 Micro Pins at constant signal (0 or 1) Burned out pins (too much current or voltage placed on pin), software Peripherals malfunctioning Observation(Volt meter/ oscilloscope) Low M3 MCLR always 0 Broken reset button, burned out pin, shorted decoup caps Micro useless due to always sin reset Observation (voltmeter) Low M4 MCLR always 1 Broken reset button, burned out pin Mirco cannot recover without turning off power (for debug purposes only) Observation (voltmeter) Low

Micro and Reset

FMECA SD Card, Push Buttons, Column Inputs, Row Select Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection CriticalityRemarks SD1 No Read/Write Functionality to SD Damaged SD Card, Shorted Decoup Caps, LM1117 Failure, SPI malfunction Cannot read or store player data Observation (Plug into PC and check if data written, Attempt to read player data via USB) Low PB1 PB Inputs always low Failed pull up resistor, Shorted decoup caps, LM1117 Failure No user input can be obtained, game rendered useless Observation (Volt meter) Low C1 Input from column alsways 0 or 1 Failed opto-isolator, Failed buffer, Burned out micro pin Cannot sense tiles properly Observation (Oscilloscope.Volt meter)Low RS1 Output to row always 0 or 1 Burned out pin on micro, burned out shift register, shorted decoup caps, LM1117 failure, Software, burned out buffer Inability to sense tiles on board Observation( Voltmeter/ Oscilloscope)Low

Column Inputs Row Selection

QUESTIONS/COMMENTS?