Preliminary Design Review
Automatic Windshield Wiper System
Michael Whitfield
Anthony Harris
Renaud Moussounda
Eric Williams
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)
2
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
3
High-Level System Diagram
IR Sensor
Impedance
Sensors
Speech
Recognition
Input Signal
Conditioning
Circuitry
Microcontroll
er
MSP430
Output
Signal
Conditioning
Circuitry
Wiper
Control
System
4
IR Sensor
Windshield
Receiver
•
•
•
•
Emitter
Model: OPB 770T
Mounted inside windshield behind rear view mirror
100% reflectivity = No rain
<85% means rain or moisture is present
5
IR Sensor Integration
IR
Sensor
MSP 430
Analog to
Digital
Converter
Vout
VCC_BAR
R1
Q1
1k
Q2N2222
• 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
6
Impedance Sensors
Speed control: 2 options
1st Schmitt Triggers
Speed Control
MCU
Water closes
circuit
2nd
5V
Copper Tape
option: MCU A/D comparator
MCU
Comparator
7
Microcontroller & Control Logic
•
•
•
•
14 I/O pins
16-MIPS performance
16-bit Sigma Delta Analog-to-Digital converter
LED display
8
Software Block Diagram
POWER ON
SYSTEM
FAILURE
EXIT
Auto?
SPEED
CONTROL
SYSTEM
CHECK
WIPER
ON
OK?
IMPEDANCE
SENSOR
SPEECH?
Water?
IR
SENSOR
Water?
9
System Integration
Design System
Sensors
12 V
MCU
Electronic
Relay
Existing Automobile System
High
Automobile
Wiper
System
Low
Park
Wiper
Switch
Intermittent
10
Test Apparatus
11
Test Apparatus (cont.)
12
Marketing and Cost
INITIAL
ESTIMATE
(MIDPOINT)
Team Design Hrs
Labor Cost(@ $30.00/hr)
206 hrs
$6,180
ACTUAL
(MIDPOINT)
162 hrs
$4,860
PROJECT
ESTIMATE
REVISED PROJECT
ESTIMATE (w/Voice
Activation)
412 hrs
460hrs
$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
13
Timeline
Task
Test all individual components
Integration of sensors w/ Microcontroller
Integration of Microcontroller w/ Motor
Construct Test Apparatus
Program Microcontroller
Project Integration
Completion
Date
11/2
11/10
11/18
11/21
11/26
12/3
14
Problems
• Interfacing with the wiper motor control
system
• Degradation of exposed impedance
sensors
• Sunlight interference of IR sensor
performance
15
Future Work
• Addition of speech recognition capabilities
• Activation of window control
• Activation of headlights
• Fog detection
16
Questions
If you build it, they
will come….
17