Emergency Braking Notification System

Applying technology of wireless sensor networks to automobiles

by

Ricardo Joseph Estevez

B.S., University of Colorado at Colorado Springs, 2002

A thesis defense submitted to the Graduate Faculty of the University of Colorado at Colorado Springs

in partial fulfillment of the

requirements for the degree of

Master of Science

Department of Computer Science

2006

Overview

Introduction Technology Review Experiment Questions Prototype Architecture Prototype Discussion Brake Distance Formula Prototype Test Video Next steps Questions and Answers

Introduction

Passive collision avoidance safety system prototype has been built as a result of this thesis research

Wireless sensor network carry inter-vehicle messages. Proved to be possible at highway speeds (60MPH)

Data fed into WSN originates from vehicle on board diagnostic (OBD) computer

Technology Review - 1

Crossbow MICA2 mote

Technology Review - 2

Crossbow MIB500 programmer board

Technology Review - 3

ELM327 IC (OBD reader

Technology Review - 4

Intelligent Transportation System Intelligent Infrastructure Intelligent Vehicles

Colorado Denver TREX http://www.cotrip.org

More implemented efforts on infrastructure Less on vehicles because of cost of

implementation

Experiment Questions

1. How can data from car’s on board diagnostic computer be captured?

2. How can the open-source OBD programs be modified for use in this safety system?

3. What is the maximum distance that a sent radio message can be received?

4. How does communication from PC to sender-mote occur?

5. How is data transmitted from sender-mote to receiver-mote?

6. How is the driver warned of the braking level?

Prototype Architecture

Prototype Discussion

Hardware Used ELM 327 IC Two Crossbow MICA2 motes

Running TinyOS 2.0 or T2 Running custom programs for lead and trailing vehicle

Host PC Communication Interfaces

RS232 Serial Communication OBD Communication Wireless Communication

Brake Distance Formula

€

d =Vo

2 −Vf2

2a

€

d =Vo

2 −Vf2

2a=

882 − 80.72

2(33)≈ 18.75 feet

Brake Distance Formula + Reaction Time

€

d =Vo

2 −Vf2

2a=

882 − 80.72

2(33)≈ 18.75 feet

€

α mileshour

×5280 feet

mile×

hour

60 minutes×

minute

60 seconds=∂ × 5280

3600feet

second

if α = 65, then 65 × 5280

3600= 88 feet

second

if reaction time, tR, is 1.5 seconds, then reaction distance is 132 feet

Prototype Test Video - Green to Red LED illumination

Prototype Test Video - Red to Green LED illumination

Road Test Threshold Graph

0

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

5 0

5 5

6 0

6 5

7 0

7 5

1 3 1 6 1 9 1 1 2 1 1 5 1 1 8 1 2 1 1 2 4 1 2 7 1 3 0 1 3 3 1 3 6 1 3 9 1 4 2 1 4 5 1 4 8 1 5 1 1 5 4 1 5 7 1

T i m e i n M i l l i s e c o n d s

MPH

Next Steps

The architecture that this prototype uses is a foundation for more research

Required brake distance formula assumes a deceleration rate. This should be specific to the vehicle, i.e. a Corvette will stop faster than a Hummer

Formula does not factor in frictional forces such as tires and road conditions. This will affect braking distance

Next Steps

The architecture that this prototype uses is a foundation for more research

Required brake distance formula assumes a deceleration rate. This should be specific to the vehicle, i.e. a Corvette will stop faster than a Hummer

Formula does not factor in frictional forces such as tires and road conditions. This will affect braking distance

Questions and Answers