Download Household Appliance Monitoring System SDMay0204

Household Appliance Monitoring System
SDMay0204
April 30, 2002
Advisors: Dr. Lamont
Prof. Patterson
Team: Paul Jonak – EE
Stephen Woerdehoff – EE
Jason Muehlmeier – EE
Yohan Blount - EE
Presentation Outline
Problem Statement
Design Objectives
End-Product Description
Assumptions and Limitations
Technical Approach
Evaluation of Project Success
Recommendations for Further Work
Human and Financial Budgets
Lessons Learned
Closing Summary
Problem Statement
Make user more aware of their power usage
Evaluate safety & condition of older appliances
Design hardware & software for data-logging watthour meter
Typical cost of data-logging watt-hour meter $500
Design Objectives
Minimal technical knowledge and skills
required of the user
Conveniently portable
Small size ( 6 x 3 x 8”)
Operable in typical residential settings
Utilize outdated computers
End-Product Description
Accurately measures power of a single
appliance
Records power data with Visual Basic
program through serial ports
Data analysis on a Windows 95 compatible
computer
Easy to use Java-encoded graphical analysis
Assumptions
User can operate a simple windows interface
Computer has two available serial ports
Local utility rates are known by user
Limitations
Standard 120V single phase appliances
Appliance will not exceed 15A
Single appliance measurement
Household has modern electrical system
Data file size
Technical Approach (Hardware)
Microcontroller-Based Recording
Wattmeter
Data Logging Wattmeter
Analog Wattmeter
Digital Wattmeter
X-10 Modules
X-10 Module Approach
The X-10 approach was too
complex due to:
Communication protocol
Development of new
transceiver hardware
Analog Wattmeter Approach
Recording real power with
analog wattmeter did not work
because:
Coil voltage not proportional to
watts
Reading not based on
d’Arsonval movement
Our Approach
Neutral
Load
Hot
CT
Voltage
Measurment
Serial
Communication
A/D
Wall Plug
Hot
Neutral
5V
Gnd
Input
5V
Supply
5V
AD7823
Driver
A/D
Current
Measurment
RS 232
DS14C232
AD7823
LP2954
Two 8 bit A/D converters
RS232 Driver
Oscillator
Current Transformer
Scaling Circuitry
Computer
Current Measurement
Wall Plug
Neutral
Hot
Hot
Neutral
Gnd
Gnd
Pins
AD7823
Vin-
1K
A/D
Vin+
Neutral
Current Transformer and
1kΩ resistor convert 0-15A
signal to 0-5V waveform.
Gnd
Load Being
Measured
Hot
Voltage Measurement
Wall Plug
Neutral
Hot
Hot
Neutral
Gnd
Gnd
0
Pins
10K
AD7823
Vin-
A/D
Vin+
Neutral
20K
Load Being
1M
Hot
Gnd
Measured
Voltage divider circuit converts 0-126VRMS
signal to 0-5V waveform.
Technical Approach (Software)
Input Voltage and Current Waveforms
Calculate Real Power
Calculate Reactive Power
Output to File
Display Data for the user
Technical Approach (Software)
Windows 95+ Compatible
Options: C, C++, Java, Visual Basic
– All members EE
– Choice: Visual Basic
 Easy
to learn
 Serial port programming
– Choice: Java
 Simple
graphical utilities
 Portability
User Interface
Prototype User Interface
– Enable/Disable serial
ports
– Choose output file
location
– Start/Stop monitoring
Finding Real Power
Voltage and Current Scaled Values
Multiply by scaling factors
– Current: CT turns ratio
– Voltage: Voltage divider factor
Finding Real Power
Multiply current &
voltage
waveforms
Instantaneous
Power
Finding Real Power
Average of
Instantaneous
Power is Real
Power (Watts)
Finding Reactive Power
Find Apparent Power, S
Real Power
Use Power Triangle to find Q (VAR)
Output File
Output Voltage & Current values
Output Real Power & Reactive Power
User can analyze data file with graphing
software (i.e. Matlab, Excel)
Java program developed
Project Success
Objectives that needed to be reached were:
Monitor power consumption of one device
accurately
Obsolete computer will record data
Easy to use software
Safe for use in home
Recommendations for future
Work
Recommended Improvements:
No dedicated computer to record data
Monitor more than one device
No cord attachment to computer
Next Prototype should be:
Microcontroller-based with recording and
information download capability
Human & Financial Budgets
Team Member
Yohan Blount
Paul Jonak
Jason Muehlmeier
Stephen
Total Hours
Item
Equipment &
Hardware
Poster
Total Effort
139 hours
141 hours
149 hours
156 hours
585 hours
Estimated Effort
129 hours
141 hours
133 hours
147 hours
550 hours
Original Revised
Cost
Cost
Final Cost
Estimate Estimate
$150.00
$70.00
$40.25
$50.00
$40.00
$40.00
Computer
$0.00
$0.00
$0.00
Labor
$0.00
$100.00
$0.00
Total
$200.00
$210.00
$80.25
Lessons Learned
Team SDMAY0204 gained technical knowledge regarding:
Physical & theoretical differences between real and total power
Analog and digital wattmeter implementation
Serial communication interfacing
Visual Basic programming
Team SDMAY0204 gained an appreciation for:
Realistic projection planning & deadline management
Effective communication among team members
A good definition of problem and objectives
Flexibility in solution approaches
Thorough research
Demo