DOODLE DRIVE

Presenter: Alex Curtis

Team 6

Environmental Impact TCSP

PROJECT OVERVIEW

Android application as controller

Robot vehicle with microcontroller

Path will be drawn in Android application and the vehicle will follow that path Outdoor mode with GPS, Google

Maps, Compass

Indoor mode with tilt control

CRITICALITY LEVELS

Low: Minor failures that doesn’t cause any physical damage to user Doesn’t cause any damage to the PCB E.g. Reading errors

Medium: Cause physical damage to the PCB or the vehicle E.g. Damage of the components due to overheating, inability to control

the vehicle

High: Cause injury to user/people around E.g. Burn due to touching the components that overheats

COMPONENTS FOR ANALYSIS

Microcontroller (LPC1768) Complex 100 pins , 32-bit Tj = 50 ºC λ = 2.904 e -6 MTTF: 40 years

COMPONENTS FOR ANALYSIS

Voltage Regulators (LM2596) High temperature (but with good heat sink) Tj = 25 ºC λ = 1.44e -7 MTTF: 792 years

COMPONENTS FOR ANALYSIS

H-Bridge High voltage and current High junction temperature Tj = 75 ºC λ = 6.6e-7 MTTF: 171 years

COMPONENTS FOR ANALYSIS

Compass MEMS (Micro-Electro-Mechanical Systems) –less

reliable than ICs Tj = 25 ºC λ = 5e-7 MTTF: 228 years

BLOCK DIAGRAM

PWM

FMECA Microcontroller

Failure Mode Possible Cause

Failure Effects Criticality

PWM Signal Failure

PWM pins failure • Servo and H-Bridge will not work• Vehicle unable to move• Unable to swing the ultrasonic sensors

Low

UART Signal Failure

UART pins failure • No GPS and Bluetooth communication.

Low

I2C Signal Failure I2C pins failure • Compass failure Low

GPIO Signal Failure

GPIO pins failure • Ultrasonic sensors failure• Fuel Gauge failure

Low - Medium

FMECA Compass

Failure Mode Possible Cause Failure Effects Criticality

Compass failure R1 & R2 failure (Pulled up resistors)

Incorrect reading of the compass

Low

FMECA

H-Bridge

Failure Mode Possible Cause

Failure Effects Criticality

Motor driver fails D3 – D10, C10. • Unpredictable behavior of the vehicle’s movement

Medium - Low

FMECA Voltage Regulators (3.3V and 5V)

Failure Mode Possible Cause Failure Effects Criticality

Vout = 0V L2, C4, D2, C3 • Components using the 3.3V regulators will not operate.

Low

Vout > 3.3V

Vout > 5V

C4 (3.3V) or C2 (5V)

• Overheating of components

High –cause burn when touched

Vout unpredictable

L2, C4, D2, C3 • Unpredictable behavior of components• 5V – ultrasonic sensors and servo• 3.3V – compass, GPS, Bluetooth etc.

Medium –unable to control the vehicle

THANK YOU!

Questions / Discussions

MICROCONTROLLER

1: Compass (I2C)2: Bluetooth (UART)3: GPS (UART)4: H-Bridge (PWM, GPIO)5: Ultrasonic (GPIO)6: Optical Encoders (Input Capture, GPIO)7: Crystal Oscillator8: Fuel Gauge (GPIO)9: Servo (PWM)

1

3

7

8

2

4

9

5 6

H-BRIDGE

COMPASS

VOLTAGE REGULATORS