Transcript Title of presentation goes here

MDR Presentation
Friday December 7, 2012
Reviewed by: Prof. Bardin & Prof. Gao
Paulo Leal, Kevin Okiah, Chris Finn
& Tim Mirabito
Department of Electrical and Computer Engineering
Outline
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PDR Recap
MDR Goals/Progress
Design Choices
CDR Goals
Demos
Cost Breakdown
Questions?
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PDR Recap
 Project Goal
Give people a means to monitor and control the
electrical devices within their households.
 Motivation
• Energy conservation has a significant social &
economic impact.
• It is hard to conserve energy because
• Limited quantitative data
• Limited social awareness
• Limited residential control
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PDR Recap: Block Diagram
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PDR Recap: Communication Flow
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Tim’s MDR Goals/Progress
 Understand Watt Meter Design
 Draw schematics of Kill-a-watt subsystems
 Communicate With Xbee
• Route current and voltage signals to Xbee
 Proprietary Design
• Transformer less power supply
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Design Choice: P4400 Watt Meter
Front Side PCB
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Back Side PCB
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Design Choice: P4400 Watt Meter
watt meter analog board schematic showing the input and output from
the wall socket, as well as the probe points for the current sense resistor
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Design Choice: P4400 Watt Meter
watt meter transformer less power supply schematic showing the input
from the analog board and the output connections to the microchips
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Design Choice: P4400 Watt Meter
watt meter LM2902 quad op amp schematic showing the input from the
analog board and power supply followed by the output connections to the
microcontroller
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Design Choice: Proprietary Design
transformer less power supply design
schematic for a 15V and 50mA output.
The top right graph shows the simulated
15V voltage output and the bottom right
graph shows the simulated 50mA current
output.
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Design Choice: Proprietary Design
Initial PCB layout for the transformer less power supply design schematic with a 15V
and 50mA output.
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Design Choice: Proprietary Design
Utilization of instrumentation amplifier chosen for high CMRR. This is
essential to provide greater precision for measuring differential voltage
across a current shunt resistor. This chip has an CMRR of 120dB.
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Design Choice: Proprietary Design
Using the current design of the XBee Explorer as a foundation, the final
implementation of the watt meter PCB will have a subsystem with pin out
headers for easy insertion of an XBee module
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Tim’s CDR Goals
 Complete proprietary design of watt meter
subsystems
 Integrate relay and XBee layouts into proprietary
design
 Complete schematic and PCB layouts for a fully
functioning system
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Paulo’s Goals/Progress
 Networking Circuit
• Setup XBee Network
• Transmit data wirelessly from model A to B
 Relay Circuit
• Design
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Design Choice: XBee Wireless Radios
 XBee Series 1
• Indoor Range: 100ft.
• More than enough for average room
• RF Data Rate: 250Kbps
• Sufficient for our application
• Frequency: 2.4 GHz
• Channel hopping to avoid Wi-Fi interference
• AES encryption
• Secure wireless data transmissions
• Analog to Digital converter
• Digitalize analog inputs from watt meter
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Design Choice: Transmission Frequency
 One of the problems encountered in the transmission
of data between the XBee and Raspberry pi was
generating the necessary current from the Kill-a-Watt
device.
 In the initial approach to this solution we use a
10000uF capacitor biased at 5V to yield a 50mA
current. Based on the following formula, we
calculated the discharge time to be approximately 17
ms, which would simulate the period of a sine wave
at 60Hz.
Where Vo = 5V R = 100 ohm and
C = 10000uF
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Design Choice: Switching Mechanism
 PowerSwitch Tail for 110-120vac
• Provide single pole switching at 20 amps
• 5300vrms isolation
• Driving voltage as little as 3vdc @ 3ma
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Design Choice: Relay Circuit
 Xbee
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Triggering mechanism
 Decoupling Capacitors
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C1 – remove lower frequency
 noise coming from the wall power supply
C2 – remove higher-frequency noise
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coming from Voltage regulator
NPN Transistor
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Provides 5V of direct current to relay
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Paulo’s CDR Goals
 Integrate relay and XBee layouts into proprietary
design
 Develop tablet/phone app (SDK interface)
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Christopher’s MDR Goals/Progress
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Setup web server
Setup database
Receive input from XBee
Parse input
Store input in database
Allow connection from user interface to database
• Over LAN
• Over internet
 Relay circuit control
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Design Choice: Raspberry Pi
 700 MHz ARM computer
• Runs custom Debian Linux
• Utilize Linux packages
 SD Card for storage
 Ethernet Port
• Utilized for connection to HomePlug
 2 USB ports
• Utilized for data input from XBee module
 Low cost
 Small profile
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Design Choice: Software
 Apache service
 MySQL database
• Efficient & lots of resources
 Avahi-daemon
• Sets Raspberry Pi hostname (solves dynamic IP problem)
 PHP
• Enable user interface to query database
 Python
• pySerial module for receiving XBee input data from USB &
for sending commands to XBee
• MySQLdb module for insertion of input data
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Design Choice: MySQL Database Structure
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Design Choice: STUNT
 Web server must be accessible from behind router
 Network Address Translation(NAT) makes this
tricky…
 Solution: Simple Traversal of UDP Through NATs
and TCP too (STUNT)
• allows applications running behind a NAT to determine
external IP and port-binding properties, allowing
applications to establish TCP sessions between two
NAT'ed hosts
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Design Choice: HomePlug Communication
 Communicate via Raspberry Pi Ethernet port
 Package communication data in Ethernet packets
 Implement SSL for secure end to end
communication
Secure SSL Channel
via Ethernet cable
via Electric line
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Christopher’s CDR Goals
 Implement MySQL structure
 Transition from Ethernet internet connection to
wireless
 Receive commands from user interface
 Create function to form & send XBee command
packets
• Will be used for initialization of XBee modules & for
controlling the relay circuit
 Setup STUNT
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Kevin’s MDR Goals/Progress
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Develop a Basic user interface
prototype that is functional across all
operating system
Come up with a plotting functionality
Demonstrate plotting data by
successfully querying from the
database
Function to take in user input and
manipulate the data as specified
Function to assimilate new devices to
the system
Function to receive and send relay
Signal
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Design Choice: Browser Based User Interface
 Cross Platform
Network
Interface
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Design Choice: Browser Based User Interface
Plotting functions
 FLOT
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AwesomeChartJS
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Design Choice: Browser Based User Interface
Programing Languages
 HTML5
 CSS
 JavaScript
 PHP
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User Interface CDR Goals
 Develop a function to take in user input and
manipulate the data as specified then plot the data
 Develop a function to assimilate new devices to the
system
 Develop a function to receive and send relay signals
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Demos!
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Prototype
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Prototype Communication Flow
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Cost Breakdown
QTY
UOM
Unit Price
Description
Total
1
1
$35.00
Raspberry PI Model B
$35.00
2
1
$19.49
P3 International P4400 Kill A Watt Electricity
Usage Monitor
$38.98
1
1
$49.99
Actiontec PWR511K01 500 Mbps HomePlug
HD Power line Wall Plug Network Adapter
$49.99
1
1
$3.95
Jumper Wires Premium 6“ M/F Pack of 10
$3.95
1
1
$3.95
Jumper Wires Premium 6" F/F Pack of 10
$3.95
1
1
$18.50
Power-Switch Tail 120 Kit for 110-120vac
mains (PN PSTK-120)
$18.50
2
1
$19.00
XBee Series 1 XB24-AWI-001
$38.00
Total 188.37
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Questions
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