Safety Analysis Ian Bacon Zach Dicklin Amy Ritter Eric Yee

Definition of Criticality Levels Safety Analysis Definition of Criticality Levels Loss of some functionality, reparable by user Loss of some functionality, not reparable by user Device unusable, reparable by user Device unusable, not reparable by user Device is a personal injury risk

Components for Analysis Safety Analysis Components for Analysis Power Circuitry Microcontroller SD Memory Card LCD Module

Safety Analysis 1) Power Circuitry

1) Power Circuitry Safety Analysis # Failure Mode Possible Causes Effects of Failure Method of Detection Criticality Probability Remarks A1 Circuit is not powered LDO failure Disconnected power component Power supply failure, disconnect -Device is unusable -Observation status LEDs -Test with DMM 3, 4 A2 Power is unregulated PCB trace short -Damage to critical components -Device operates erratically -Fire hazard 2,4,5

Safety Analysis 2) Microcontroller

2) Microcontroller Safety Analysis # Failure Mode Possible Causes Effects of Failure Method of Detection Criticality Probability Remarks B1 Peripheral components damaged Shock Unregulated power Physical damage -Comm.with peripheral lost or erradic -Device is unusable -Observation 2, 4 .58E-6 B2 Critical components damaged -Device operated erradically 2,4

Safety Analysis 3) SD Memory Card

3) SD Memory Card Safety Analysis # Failure Mode Possible Causes Effects of Failure Method of Detection Criticality Probability Remarks C1 Read failure Physical damage Power surge -Incorrect data read -Device is unusable -Software error detection 1,3 Easy, cheap, user fix C2 Write failure Write lifetime exceeded -Incorrect data writes -Incorrect data reads Depends on update frequency, likely between 2E-6 and 4E-6

Safety Analysis 4) LCD Module

4) LCD Module Safety Analysis # Failure Mode Possible Causes Effects of Failure Method of Detection Criticality Probability Remarks D1 Connection failure Physical damage, disconnect -Displays incorrect or garbled data -Device is unusable -Observation 1, 3 Easy fix D2 Power failure -Disconnect -Damaged power adapter -Controller board power supply failure -Blank display 3,4 D3 Backlight failure Display lifespan exceeded Power surge 4 25E-6 Failure likely in <5 years

4) LCD Module (conti.) Safety Analysis # Failure Mode Possible Causes Effects of Failure Method of Detection Criticality Probability Remarks D4 Controller board failure Physical damage Power surge -Displays behaves erratically -Display is blank -Device is unusable -Observation -Software detection 2,4