Team 16 : Project Minotaur Presenter : John Hubberts Project Overview Home security robot capable of monitoring the user’s home while they’re away. Can be manually controlled through a website or configured to patrol the house autonomously. Uses Kinect to capture video and identify intruders.

Formal Definition of Criticality Levels High Criticality Failures that could result in physical danger for the user. Acceptable mean failure rate: λ < 1e-9 Moderate Criticality Failures that could cause irreparable damage to the device, but wouldn’t pose danger to the user. Acceptable mean failure rate: λ < 1e-7 Low Criticality Failures that could limit but not eliminate the device’s capabilities. Acceptable mean failure rate: λ < 1e-6

Highest Risk Components Microcontroller (PIC24FJ128GA) High Complexity Widely used High Noise H-Bridge (L298P013TR) Handles large currents Potential for stalling if motors are stuck Switching Regulators (TPPS5450-Q1– 7.2V, LM25085 – 12.0V) Have the ability to draw substantial amounts of current from the battery (From our experience) heats up very rapidly

Microcontroller (PIC24FJ128GA) MIL-HDBK-217F Classification : MOS Digital Microprocessor λp = (C1 x πτ + C2 x πE) x πQ x πL Parameter Description Value Comment C1 Die complexity 0.28 Up to 16 bit Microprocessor πτ Temperature coefficient 0.6 TJ = 125° C C2 Pin-based constant 0.032 64-pin Non-Hermetic SMT πE Environmental Constant 4 Ground Mobile πQ Learning factor 1 More than two years in production πL Quality factor 10 Commercial Quality λp 2.96 MTTF 38.5 Years

H-Bridge (L298P013TR) MIL-HDBK-217F Classification : MOS Digital and Linear Gate Array Device λp = (C1 x πτ + C2 x πE) x πQ x πL Parameter Description Value Comment C1 Die complexity .01 <100 transistors πτ Temperature coefficient 3.4 TJ = 150° C C2 Pin-based constant 0.0082 18-pin Non-Hermetic SMT πE Environmental Constant 4 Ground Mobile πQ Learning factor 1 More than two years in production πL Quality factor 10 Commercial Quality λp 3.728 MTTF 30.62 Years

7.2V Switching Regulator (TPPS5450-Q1) MIL-HDBK-217F Classification : MOS Digital and Linear Gate Array Device λp = (C1 x πτ + C2 x πE) x πQ x πL Parameter Description Value Comment C1 Die complexity .04 <1000 transistors πτ Temperature coefficient 0.6 TJ = 125° C C2 Pin-based constant 0.0025 6-pin Non-Hermetic SMT πE Environmental Constant 4 Ground Mobile πQ Learning factor 1 More than two years in production πL Quality factor 10 Commercial Quality λp 0.34 MTTF 344.2 Years

12V Switching Regulator (LM25085) MIL-HDBK-217F Classification : MOS Digital and Linear Gate Array Device λp = (C1 x πτ + C2 x πE) x πQ x πL Parameter Description Value Comment C1 Die complexity .04 <1000 transistors πτ Temperature coefficient 0.6 TJ = 125° C C2 Pin-based constant 0.0034 8-pin Non-Hermetic SMT πE Environmental Constant 4 Ground Mobile πQ Learning factor 1 More than two years in production πL Quality factor 10 Commercial Quality λp 0.376 MTTF 303.60 Years

Schematic (Microcontroller)

FMECA (Microcontroller) Failure Mode Failure Cause Failure Effect Detection Method Criticality Overheat 3.3V switching regulator or battery failure Loss of motor/sensor control, large heat dissipation Observation High Output stuck at ‘1’s Internal chip damage Motor will drive indefinitely at full speed (potential stall) Observation (if stall), probing headers Medium (High) Output stuck at ‘0’s Proximity sensors won’t register. Robot may drive off ledge Medium

Schematic (H-Bridge)

FMECA (H-Bridge) Failure Mode Failure Cause Failure Effect Detection Method Criticality Chip acts as net open circuit 7.2V switching regulator failure Overdrive motors, cause stall or overheat Observation High Unable to source current 7.2V switching regulator failure, internal component failure No control over motors Moderate

Schematic (7.2 V Switching Regulator)

Schematic (12 V Switching Regulator)

FMECA (Switching Regulators) Failure Mode Failure Cause Failure Effect Detection Method Criticality 7.2V Regulator 0V out Overheat leading to chip failure Loss of motor capabilities Observation Moderate 7.2V Regulator Short Battery failure resulting in overdraw Overheating, overdriving H-Bridge High 12V Regulator 0V out Loss of motherboard functionality Observation No control packets received 12V Regulator Short Overheating, potential to fry Atom board

Questions?