1

Preliminary Design Review

Automatic Windshield Wiper System

Michael Whitfield

Anthony Harris

Renaud Moussounda

Eric Williams

22

Project Overview

• Automated Windshield Wiper System– Improve safety by decreasing driver distraction– Target Automobile Manufacturers/ After-market

Customers

• Goals– Detect rainfall on windshield– Detect intensity of rainfall– Automatically activate windshield wipers once rainfall

is detected– Voice-controlled system activation/deactivation

(Future)

3

Project Status

• Online project management• IR sensor, Humidity sensor,

MSP430(Microcontroller) ordered and obtained

• Test apparatus designed • Impedance sensor designed, built, and

tested• Project budget/hours updated • Project scope fully defined

4

High-Level System Diagram

Microcontroller

MSP430

IR Sensor

Impedance Sensors

Speech Recognition

Input Signal Conditioning

Circuitry

Output Signal

ConditioningCircuitry

Wiper Control System

5

IR Sensor

EmitterReceiver

Windshield

• Model: OPB 770T• Mounted inside windshield behind rear view mirror• 100% reflectivity = No rain• <85% means rain or moisture is present

6

IR Sensor Integration

• Turn current output into a voltage

• Feed voltage through A to D converter

• Microcontroller takes digital output from A to D converter and makes decisions

Q 1

Q 2 N 2 2 2 2

V C C _ B A RR 1

1 k

V o u t

IR Sensor

MSP 430Analog to

Digital Converter

77

Impedance Sensors

Speed control: 2 options1st Schmitt Triggers

2nd option: MCU A/D comparator

5V Water closes

circuit

MCU

Speed Control

MCUComparator

Copper Tape

8

Microcontroller & Control Logic• 14 I/O pins• 16-MIPS performance • 16-bit Sigma Delta Analog-to-Digital converter• LED display

99

Software Block DiagramPOWER ON

SYSTEMCHECK

IRSENSOR

IMPEDANCE SENSOR

Auto?

SYSTEMFAILURE

WIPERON

SPEECH?

Water? Water?

OK?

SPEED CONTROL

EXIT

10

System Integration

MCU

AutomobileWiper

System

WiperSwitch

High

Low

Intermittent

Park

ElectronicRelay

12 VSensors

Existing Automobile System

Design System

11

Test Apparatus

12

Test Apparatus (cont.)

13

Marketing and CostINITIAL ESTIMATE(MID-POINT)

ACTUAL (MID-POINT)

PROJECT ESTIMATE

REVISED PROJECT ESTIMATE (w/Voice Activation)

Team Design Hrs 206 hrs 162 hrs 412 hrs 460hrs

Labor Cost(@ $30.00/hr) $6,180 $4,860 $12,360 $13,800

(11% Increase)

Parts Cost (Prototype Design)

N/A N/A $239 $350

Parts Cost (Manufactured) N/A N/A $140 $205

Price N/A N/A $600* $800*

Profit Margin N/A N/A 16%* 15.4%*

*Figures based on 500 units sold

14

TimelineTask Completion

DateTest all individual components 11/2Integration of sensors w/ Microcontroller 11/10Integration of Microcontroller w/ Motor 11/18Construct Test Apparatus 11/21Program Microcontroller 11/26Project Integration 12/3

15

Problems

• Interfacing with the wiper motor control system

• Degradation of exposed impedance sensors

• Sunlight interference of IR sensor performance

16

Future Work

• Addition of speech recognition capabilities

• Activation of window control

• Activation of headlights

• Fog detection

17

Questions

If you build it, they will come….