Home Enhancement Suite

Home Enhancement Suite

Presenter: Allen Humphreys

William Bouchonnet, Daniel Sabo, Nathan Irvin

Summary• Definition of Design’s Criticality Levels

• Components Under Consideration

• Failure Modes, Effects, and Criticality Analysis

PSSCs• An ability to detect a user based on RFID and determine

which user has priority, displaying the user's identity on an LCD.

• An ability to adjust the light intensity to match a user’s settings through X-10 protocol.

• An ability to adjust a television set or other HDMI device using CEC-HDMI protocol, to a user's preferred settings. (ON/OFF, Channel, Volume)

• An ability to unlock a door when an acceptable RFID is present.

• An ability to select/set preferred settings through an embedded web server and the ability to save the "light settings" with the press of a button.

Reliability & Safety Analysis

Reliability & Safety Analysis

• High Criticality

• Potential Harm to User

• Medium Criticality

• Irreparable Damage

• Low Criticality

• Inconvenience, single feature failure

Reliability & Safety Analysis

• Power Supply System• Heat

• Microcontroller System• Die Complexity • Failure Rate C1 = .56 for 32-bit µC

• Ethernet System• Component Complexity• 29 Passive Components

Power Supply

FMECA Analysis – Power Supply

Failure No.

Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality

Remarks

A1 Either Supply Output = 0V

Failure to short circuit of any component in power supply

Circuit inoperable

Observation Medium 1A Fuse Protects Against Fire

A2 5V Supply > 5V

Failure of T1 or U9

Damage to U10, PLIX chip, RFID Reader

Observation Medium 3.3V Supply Could Fail On This

A3 3.3V Supply > 3.3V

Failure of T1, U9, or U10

Potential damage to µC

Observation Medium

A4 Output out-of-tolerance

Failure to open circuit of any component in power supply

High ripple or out-of-spec operating voltage; Circuit Behavior Unpredictable

Observation Medium

Microcontroller

FMECA Analysis - Microcontroller

Failure No. Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality Remarks

B1 Lock Circuit Unknown

R16, U3, Software

Security Breach

Observation High Possible Injury by 3rd Party

B2 Light Failure R14, U4, Software

Loss of Light Control

Observation Low

B3 Stuck in reset R6, S1, R5, C10, Software

Micro will not operate

Observation Medium

B4 Receives < 3.3V

Bypass Capacitors C3, C4, C5, C6, C8, C7 Short

Micro will not operate, Unpredictable Outputs

Observation Medium

FMECA Analysis - Ethernet

Failure No. Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality Remarks

C1 External Oscillator Failure

U8 Ethernet Fails, µC Fails

Observation Medium Interaction with µC is unpredictable

C2 Noise Suppression Caps Fail

C30, C29, C28, C31

No/Poor Ethernet Comm.

Observation Low

C3 Communication to µC Fail

R39 Open Circuit

No Ethernet Observation Low

Questions?