Team We Ate 9 FMECA Worksheet
A. Power Supply
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
B. RF Regulator
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
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
D. RF Communication
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
E. Accelerometers
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
F. Sensors
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