1. 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.

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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
Years

8. Schematic (Microcontroller)

9. 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

10. Schematic (H-Bridge)

11. 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

12. Schematic (7.2 V Switching Regulator)

13. Schematic (12 V Switching Regulator)

14. 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

15. Questions?