Madalina Vintila David Wilkinson Michelle Zhang Zac Greenawalt

Overview Accelerometer based character recognition device Battery powered pen Wall/battery powered base station Wireless communication betwixt pen and base L

What is the worst thing that could happen?

Component Failure Selection Table ADXL330 Accelerometer ParameterValueComments C1C1.011 to 100 transistors, Linear, MOS TT 3.8Max temp 70 C C2C pins, 7 functional EE 4.0Ground mobile QQ 10Commercial LL 1.0>2 Years in production P.516Failures per 10 6 hours MTTF1,937,984 hours = 221 Years Table PIC18F2320 Microcontroller ParameterValueComments C1C1.14CMOS, 8-Bit TT.71Max temp 50 C C2C pins EE 4.0Ground mobile QQ 10Commercial LL 1.0>2 Years in production P 1.514Failures per 10 6 hours MTTF660,512 hours = years Table LT1302 Boost ParameterValueComments C1C1.011 to 100 Gates, Linear, MOS TT 3.8Max temp 70 C C2C pins EE 4.0Ground mobile QQ 10Commercial LL 1.0>2 Years in production P.516Failures per 10 6 hours MTTF1,937,984 hours = 221 Years

Functional Blocks Section A Section B Section C

Accelerometer Failu re No. Failure ModePossible CausesFailure Effects Method of Detection Criticalit y Remarks A1Muddy analog signals are sent to the micro C14, C15, C18 have been destroyed or shorted The simplest of characters are not recognized Observation on LCD LowEasy replacement of parts

Microcontroller Failu re No. Failure Mode Possible CausesFailure Effects Method of Detection Criticali ty Remarks B1Microcontroll er will not leave reset state SW TACT has failed in closed state Microcontroll er fails to run program Observation on LCD LowEasy replacement of part B2Base station does not detect end of character SW2 has failed in closed state Buffer overflows on base station and an end of character signal is not received Observation on LCD LowEasy replacement of part B3Base station does not detect beginning of character SW2 has failed in open state Sampling of acceleromete r is not done due to faulty pushbutton ObservationLowEasy replacement of part

Transceiver Failu re No. Failure Mode Possible CausesFailure Effects Method of Detection Criticalit y Remarks C1Communicati on between the base and pen cannot be made. Transceiver has failed Permanent loss of communicatio n between pen and base ObservationLowEasy replacement of part

Functional Blocks Section D Section E

Fuel Gauge Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection CriticalityRemarks D1Battery status does not change or update Fuel Gauge has failed Microcontroller no long receives interrupt and does not update battery status Observation on LCD MediumDifficult to replace part D1Battery status does not change or update R_sense has been shorted Fuel gauge no longer counts coulombs and does not trigger interrupt on micro ObservationLowEasy replacement of part

Fuel Gauge

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