Reliability and Safety Analysis

(Left to Right)

Matt FinnBrian Crone

Samuel OshinYonatan Feleke

Project Overview Future Cash Register

• The future cash register is a point of sale box designed to make wireless transactions through the use of Near Field Communications protocol.

• It will accept payments and send receipts through NFC. It will also aide the cashier with orders through voice recognition.

Project-Specific Success Criteria Ability to customize the inventory via the user

interface (Atom)

Ability to communicate with an NFC device (dSPIC30)

Ability to interface with an IR sensor to detect the presence of a user (dSPIC30)

Ability to display prompts to user through LCD (dSPIC30)

Ability to aid cashier by highlighting menu choices while placing order with voice recognition (Atom)

Block Diagram

Definition of Criticality Levels

High• System irreparable• Potential for user injury

Medium• System irreparable• Little/no potential for user injury

Low• System still functional• User inconvenience

Components Under Consideration Voltage Regulator

RS232 Level Translator

Microcontroller

NFC Controller

Voltage Regulator - λP C1 = .02 (101 to 300 transistors) πT = 16.0 (<100˚C) C2 = 0.0012 (3 pins) π E = 2.0 (Ground fixed

environment) π L = 1.0 ( > 2 years) π Q = 10.0 (Commercial Grade)

λP = (C1 x πT + C2 x πE ) x π L x πQ

= 3.224 failures/106 hours

FMECAFailure No. Failure

ModePossible Causes

Failure Effects

Method of Detection

Criticality

Voltage RegulatorA1 Output = 0V Failure of

regulator or passive components, external short

Unable to operate

Observation, package heating up, no response from micro to GUI

Medium

A2 Output > 5V Regulator Failure

Component destruction, Overheating

Observation High

A3 Output out of tolerance

Regulator, Passive Component Failure

Operating voltages wrong, unpredictable

Observation, voltage probes

Medium

RS232 Translator - λP C1 = .02 (101 to 300 transistors) πT = 7.0 (<85˚C) C2 = 0.0072 (16 pins) π E = 2.0 (Ground fixed

environment) π L = 1.0 ( > 2 years) π Q = 10.0 (Commercial Grade)

λP = (C1 x πT + C2 x πE ) x π L x πQ

= 1.544 failures/106 hours

FMECAFailure No. Failure

ModePossible Causes

Failure Effects

Method of Detection

Criticality

RS232 TranslatorB1 Output = 0V Failure of

translator or passive components, external short

Atom and Micro unable to communicate

Observation, No messages from micro

Medium

B2 Output not translated

MAX3232 Failure

Atom and Micro unable to communicate, high voltage to Micro

Observation, Voltage probes, no messages from micro

Medium

Microcontroller - λP C1 = .28 (16-bit, MOS) πT = 3.1 (125˚C) C2 = 0.032 (64 pins) π E = 2.0 (Ground fixed

environment) π L = 1.0 ( > 2 years) π Q = 10.0 (Commercial Grade)

λP = (C1 x πT + C2 x πE ) x π L x πQ

= 9.32 failures/106 hours

FMECAFailure No. Failure

ModePossible Causes

Failure Effects

Method of Detection

Criticality

MicrocontrollerD1 Output

continuously 0

Software, Passive Components, Short

System not functional, blocks not communicating

Observation, Software debugging, probes

Medium

D2 Output continuously 1

Software, Passive components

Improper communication between blocks, no real functionality

Observation, check LEDs and messages on GUI

Medium

NFC Controller - λP C1 = .14 (8-bit, MOS) πT = .96 (85˚C) C2 = 0.019 (40 pins) π E = 2.0 (Ground fixed

environment) π L = 1.0 ( > 2 years) π Q = 10.0 (Commercial Grade)

λP = (C1 x πT + C2 x πE ) x π L x πQ

= 0.5144 failures/106 hours

FMECAFailure No. Failure

ModePossible Causes

Failure Effects

Method of Detection

Criticality

NFC ControllerD1 Output

continuously 0

Oscillator Failure, Passive Components, Short

NFC data will not be sent/received. Payment not possible

Observation, correct payment information not received

Low

D2 Incorrect operating frequency

Oscillator failure

Improper data communication, potential for losing data, incorrect payment information

Observation, Verify payment information with receipt

Low

Questions