Energy Monitoring and Control System Design Presentation Summary
This presentation outlines the methodologies and progress made on the development of an energy monitoring and control system for households, reviewed by Professors Bardin and Gao. The presentation reviews the project goals—monitoring and controlling household electrical devices to promote energy conservation—and discusses design choices made for the P4400 watt meter, XBee communication setup, and software architecture for data handling. Key objectives include creating a proprietary design for the watt meter, integrating relay systems, and developing a user interface for data interaction.
Energy Monitoring and Control System Design Presentation Summary
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Presentation Transcript
MDR Presentation Friday December 7, 2012 Reviewed by: Prof. Bardin & Prof. Gao Paulo Leal, Kevin Okiah, Chris Finn & Tim Mirabito
Outline • PDR Recap • MDR Goals/Progress • Design Choices • CDR Goals • Demos • Cost Breakdown • Questions?
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
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
Design Choice: P4400 Watt Meter Back Side PCB Front Side PCB
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
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
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
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.
Design Choice: Proprietary Design Initial PCB layout for the transformer less power supply design schematic with a 15V and 50mA output.
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.
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
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
Paulo’s Goals/Progress • Networking Circuit • Setup XBee Network • Transmit data wirelessly from model A to B • Relay Circuit • Design
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
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
Design Choice: Switching Mechanism • PowerSwitchTail for 110-120vac • Provide single pole switching at 20 amps • 5300vrms isolation • Driving voltage as little as 3vdc @ 3ma
Design Choice: Relay Circuit • Xbee • Triggering mechanism • Decoupling Capacitors • C1 – remove lower frequency • noise coming from the wall power supply • C2 – remove higher-frequency noise • coming from Voltage regulator • NPN Transistor • Provides 5V of direct current to relay
Paulo’s CDR Goals • Integrate relay and XBee layouts into proprietary design • Develop tablet/phone app (SDK interface)
Christopher’s MDR Goals/Progress • 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
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
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
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
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
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
Kevin’s MDR Goals/Progress • 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
Design Choice: Browser Based User Interface • Cross Platform Network Interface
Design Choice: Browser Based User Interface Plotting functions • FLOT • AwesomeChartJS
Design Choice: Browser Based User Interface Programing Languages • HTML5 • CSS • JavaScript • PHP
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 functionto receive and send relay signals
