1. Team We Ate 9
FMECA Worksheet

3. A. Power Supply

4. A. Power Supply Failure No. Failure Mode Possible Causes
Failure Effects
Method of
Detection
Criticality
Remarks A1
Output = 0
Failure of
C1,C2,C4,C5,
R1,R4,U1
Battery terminals
will be shorted
Observation
High
May cause battery to
overheat and burn the
user A2
0V < Output < 3.3V
Failure of L1, D1
Causes step up
converter to output the
battery supply voltage
Low
Circuit still works, but
will not run as long due
to inefficient use of
batteries A3
Output > 3.3V
Failure of R3
Causes step-up
converter to output
its highest capable
voltage (5.5V)
May overheat and
damage MCU, RF
module, and
accelerometers

5. B. RF Regulator

6. B. RF Regulator Failure No. Failure Mode Possible Causes
Failure Effects
Method of
Detection
Criticality
Remarks B1
Output = 0
Failure of
U7, C23, C24 (shorted circuit)
USB power rails
shorted
Observation
High
Will overheat the
regulator. (max 500mA
through board) B2
Output out of
tolerance
Failure of C23, C24 (open circuit)
RF may not work
properly.
Low
Circuit still works, but
problems may occur
with receiving signals
from glove. B3
Output = 5.0V
Failure of U7
RF module will
overheat.
None

8. C. Base MCU Failure No. Failure Mode Possible Causes Failure Effects
Method of Detection
Criticality
Remarks C1
Erratic data from USB line
Failure of R15
CPU will overheat
Observation
High
None

9. D. RF Communication

10. D. RF Communication Failure No. Failure Mode Possible Causes
Failure Effects
Method of Detection
Criticality
Remarks D1
Unable to read RF output.
Failure of U7 (voltage regulator), C23, C24, Q2 (NMOS), U6 (level translator)
No communication between glove and base
Observation
Low
No functionality

11. E. Accelerometers

12. E. Accelerometers Failure No. Failure Mode Possible Causes
Failure Effects
Method of Detection
Criticality
Remarks E1
Noisy Accelerometer Output
Failure of C6, C7, C8, C9, C10, C11, C25, C26, R5, R6, R7, R8, R9, R10
Large amount of accumulating error
Observation
Low
User will not be able to control the pointer precisely

13. F. Sensors

14. F. Sensors Failure No. Failure Mode Possible Causes Failure Effects
Method of
Detection
Criticality
Remarks F1
Output = 0V
Failure of R12, R13, R14, R17
Can’t read clicking movements
Observation
Low
None F2
Output = 3.3V
Failure of VR1, VR2, VR3