SWISH SLEEVESafety and Reliability Analysis

Stephen MacNeil, Michael Kobit, Sriharsh Achukola, Augustus Hong

Project Overview

We would like to design and implement a shooting sleeve made from compression material that basketball players or pitchers could wear to track their motion, without the use of cameras. This prevents current occlusion issues inherent in optical motion capture. The sleeve can be extended to other sports as well and beyond the scope of this class could be extended to an entire suit which could monitor sports performance in athletes.

Criticality

High Criticality

Failure that could potentially lead to injury to the user

Medium Criticality

Failure that could render components permanently non-functional.

Low Criticality

Failure that affects performance or creates disfunctionality to the device.

Critical Component

Microcontroller – PIC32MX795F512H

Synchronous Buck Regulator – LM20143

Battery Monitoring – DS2781

PIC32MX795F512H-Microcontroller

Failure No.

Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality

Remarks

A1 UART failure

Fault with the pins

Unable to communicate with atom board

Observation Medium

A2 TIMER failure

Failure to initialize or set proper length delays

Unable to maintain periodic data extraction and transmit

Observation Low

A3 I2C failure Issue with SDA and SCL pins

Unable to read the IMU data.

Observation Low

A4 Reset failure

Fault with pushbutton

Micro is unable to reset or consistently to reset

Observation Medium

Parameter name Description Value Comments regarding choice of parameter value, especially if you had to make assumptions.

C1 Die complexity 0.56 32 – bit processor

ΠT Temperature coeff. 0.71 Assume linear 50 degree C

C2 Package Failure Rate 0.025 64 pin SMT

ΠE Environmental Factor 4 Ground, Mobile

ΠQ Quality Factor 10 Commercially manufactured component

ΠL Learning Factor 1 ≥ 2 years in production

λP Part Failure Rate 4.97 Failures/10^6 hours

Entire design(MTTF): 201207 Hours = 22 Years

PIC32MX795F512H-Microcontroller

LM20143 – Synchronous Buck Regulator

Failure No.

Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality

Remarks

B1 Vout < 3.3V

LM20143 is burned out or Caps burned out

IMU, XBEE, Micro and LCD will not function

Observation

Medium

B2 Vout > 3.3V

LM20143 is shorted or Caps/resistor shorted

IMU, MICRO, LCD and XBEE might be damaged

Observation

Medium

B3 Vout < 3.3V or Vout > 3.3V

Damaged during sodering

unpredictable

Observation

Medium

Parameter name Description Value Comments regarding choice of parameter value, especially if you had to make assumptions.

C1 Die complexity 0.010 1 to 100 MOS pins

ΠT Temperature coeff. 0.71 Assumer linear 50 degree C

C2 Package Failure Rate 0.0056 16 pin SMT

ΠE Environmental Factor 4.0 Ground, Mobile

ΠQ Quality Factor 10 Commercially manufactured component

ΠL Learning Factor 1 ≥ 2 years in production

λP Part Failure Rate 0.295 Failures/10^6 hours

Entire design(MTTF): 3389830 Hours = 386 Years

LM20143 – Synchronous Buck Regulator

Failure No. Failure Mode

Possible Causes

Failure Effects

Method of Detection

Criticality Remarks

C1 Output continuously 0

DS2781 burned out, zenor diode shorted

Incorrect battery readings

Reading is 0 even after a full charge

Medium See *

C2 Output continuously 1

DS2781 shorted, or some other resistor shorted

Incorrect battery readings

Reading is 1 after long time of use

Medium See *

C3 Battery monitoring values incorrect

DS2781 burned out, circuit not implemented correctly

Incorrect battery readings

Reading is low after full charge, or high after long time of use

Medium See *

DS2781 – Battery Monitoring

*Incorrect Battery readings could lead to irregular charging cycles, and therefore decreasing the battery’s lifetime

Parameter name Description Value Comments regarding choice of parameter value, especially if you had to make assumptions.

C1 Die complexity 0.010 1 to 100 MOS pins

ΠT Temperature coeff. 0.71 Assumer linear 50 degree C

C2 Package Failure Rate 0.0026 8 pins SMT hermetic

ΠE Environmental Factor 4.0 Ground, Mobile

ΠQ Quality Factor 10 Commercially manufactured

ΠL Learning Factor 1 ≥ 2 years in production

λP Part Failure Rate 0.175 Failures/10^6 hours

Entire design(MTTF): 5714285 Hours = 651 Years

DS2781 – Battery Monitoring

Questions?