Vitalis Wireless Biometric Sensor Reliability and Safety Analysis

Vitalis Wireless Biometric Sensor Reliability and Safety Analysis ECE 477 - Spring 2013 TEAM 13 Presenter: Yi Shen Team Members: Aakash Lamba Di Mo Shantanu Joshi Yi Shen

Project Overview • Prototype of a portable wireless biometric sensor • Battery-powered device with fuel gauge • Mounted on the wrist • Monitor vital signs such as pulse rate, Sp. O 2 and skin temperature • Transmit the information via Wi-Fi for remote web access • NFC chip allows immediate access • Accelerometer on the shoulder for fall detection • Manual and automatic alarm system.

Block Diagram

Definition of Criticality Levels •

Components Failure Analysis 1. Microcontroller: Atmel – ATmega 1284 2. Light-To-Frequency Converters: TAOS – TSL 230 RD 3. Charger/Booster: Charger – MC 73831 Boost Converter – TPS 61200

Microcontroller: Atmel – ATmega 1284 Parameter MTTF MOS digital microprocessor devices (Mil-Hdbk-217 F) Description Value Die complexity failure rate 0. 14 Temperature factor 0. 98 Operating at 85 °C Package failure rate 0. 021 44 -pin SMT Environment factor 4. 0 Ground Mobile Quality factor 10 Other Commercial Level Learning factor 1 > 2 yrs in production Reliability 2. 212 Entire Design Comment 8 -bit microcontroller 51. 607 years

Light-To-Frequency Converters: TAOS – TSL 230 RD Linear Gate / Logic Array (Mil-Hdbk-217 F) Parameter MTTF Description Value Comment Die complexity failure rate 0. 01 <100 transistors Temperature factor 7. 0 Operating at 30 °C Package failure rate 0. 0034 8 -pin SMT Environment factor 4. 0 Ground Mobile Quality factor 10 Other Commercial Level Learning factor 1 > 2 yrs in production Reliability 0. 836 Entire Design 136. 55 years

Charger – MC 73831 Linear Gate / Logic Array (Mil-Hdbk-217 F) Parameter MTTF Description Value Comment Die complexity failure rate 0. 01 <100 transistors Temperature factor 7. 0 Operating at 85 °C Package failure rate 0. 0020 5 -pin SMT Environment factor 4. 0 Ground Mobile Quality factor 10 Other Commercial Level Learning factor 1 > 2 yrs in production Reliability 0. 78 Entire Design 146. 35 years

Boost Converter – TPS 61200 Linear Gate / Logic Array (Mil-Hdbk-217 F) Parameter MTTF Description Value Comment Die complexity failure rate 0. 01 <100 transistors Temperature factor 7. 0 Operating at 85 °C Package failure rate 0. 0043 10 -pin QFN Environment factor 4. 0 Ground Mobile Quality factor 10 Other Commercial Level Learning factor 1 > 2 yrs in production Reliability 0. 870 Entire Design 130. 91 years

Schematic: Section Breakdown Microcontroller Sensors External Interfaces Power and Battery Management

FMECA Chart Microcontroller: Atmel – ATmega 1284 Failur e No. Failure Mode Possible Causes Failure Effects Detection Method Criticality A 1 Failure of UART Wrong connections for TX/RX Wi-Fi and OLED won’t communicate with micro properly Inspection High A 2 Over-current Decoupling Capacitors are shorted Micro doesn’t function any more Inspection and ICD 3 debugger High A 3 Failure of I 2 C Pull-up resistors are shorted Unable to retrieve data from temp sensor and fuel gauge Inspection Medium A 4 Failure of GPIO Bad wire connections Unable to detect falling position/ control LEDs for Sp. O 2 Sensors Inspection Medium

FMECA Chart Light-To-Frequency Converters: TAOS – TSL 230 RD Failur e No. Failure Mode Possible Causes Failure Effects Detection Method Criticality B 1 Failure to operate Bad solder for GND and Vcc Micro won’t receive any data about patient pulse and blood oxygen concentration information Inspection Medium

FMECA Chart Charger – MC 73831 Failur e No. Failure Mode Possible Causes Failure Effects Detection Method Criticality C 1 Overheat Too much current Damage Battery Inspection high

FMECA Chart Boost Converter – TPS 61200 Failur e No. Failure Mode Possible Causes Failure Effects Detection Method Criticality D 1 Over-heat Too much current Output less than 5 V, OLED screen won’t be powered on Observation Medium

Questions?