1. Department of Electrical and Computer Engineering MDR Presentation Friday December 7, 2012 Reviewed by: Prof. Bardin & Prof. Gao Paulo Leal, Kevin Okiah, Chris Finn & Tim Mirabito

2. 2 Department of Electrical and Computer Engineering Outline  PDR Recap  MDR Goals/Progress  Design Choices  CDR Goals  Demos  Cost Breakdown  Questions?

3. 3 Department of Electrical and Computer Engineering 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

4. 4 Department of Electrical and Computer Engineering PDR Recap: Block Diagram

5. 5 Department of Electrical and Computer Engineering PDR Recap: Communication Flow

6. 6 Department of Electrical and Computer Engineering 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

7. 7 Department of Electrical and Computer Engineering Design Choice: P4400 Watt Meter Front Side PCB Back Side PCB

8. 8 Department of Electrical and Computer Engineering 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

9. 9 Department of Electrical and Computer Engineering 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

10. 10 Department of Electrical and Computer Engineering 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

11. 11 Department of Electrical and Computer Engineering 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.

12. 12 Department of Electrical and Computer Engineering Design Choice: Proprietary Design Initial PCB layout for the transformer less power supply design schematic with a 15V and 50mA output.

13. 13 Department of Electrical and Computer Engineering 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.

14. 14 Department of Electrical and Computer Engineering 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

15. 15 Department of Electrical and Computer Engineering 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

16. 16 Department of Electrical and Computer Engineering Paulo’s Goals/Progress  Networking Circuit Setup XBee Network Transmit data wirelessly from model A to B  Relay Circuit Design

17. 17 Department of Electrical and Computer Engineering 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

18. 18 Department of Electrical and Computer Engineering 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

19. 19 Department of Electrical and Computer Engineering 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

20. 20 Department of Electrical and Computer Engineering 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

21. 21 Department of Electrical and Computer Engineering Paulo’s CDR Goals  Integrate relay and XBee layouts into proprietary design  Develop tablet/phone app (SDK interface)

22. 22 Department of Electrical and Computer Engineering 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

23. 23 Department of Electrical and Computer Engineering 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

24. 24 Department of Electrical and Computer Engineering 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

25. 25 Department of Electrical and Computer Engineering Design Choice: MySQL Database Structure

26. 26 Department of Electrical and Computer Engineering 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

27. 27 Department of Electrical and Computer Engineering Design Choice: HomePlug Communication  Communicate via Raspberry Pi Ethernet port  Package communication data in Ethernet packets  Implement SSL for secure end to end communication via Ethernet cable via Electric line Secure SSL Channel

28. 28 Department of Electrical and Computer Engineering 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

29. 29 Department of Electrical and Computer Engineering 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

30. 30 Department of Electrical and Computer Engineering Design Choice: Browser Based User Interface  Cross Platform Network Interface

31. 31 Department of Electrical and Computer Engineering Design Choice: Browser Based User Interface Plotting functions  FLOT  AwesomeChartJS

32. 32 Department of Electrical and Computer Engineering Design Choice: Browser Based User Interface Programing Languages  HTML5  CSS  JavaScript  PHP

33. 33 Department of Electrical and Computer Engineering 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

34. 34 Department of Electrical and Computer Engineering Demos!

35. 35 Department of Electrical and Computer Engineering Prototype

36. 36 Department of Electrical and Computer Engineering Prototype Communication Flow

37. 37 Department of Electrical and Computer Engineering Cost Breakdown QTYUOMUnit PriceDescriptionTotal 11$35.00Raspberry PI Model B$35.00 21$19.49P3 International P4400 Kill A Watt Electricity Usage Monitor $38.98 11$49.99Actiontec PWR511K01 500 Mbps HomePlug HD Power line Wall Plug Network Adapter $49.99 11$3.95Jumper Wires Premium 6“ M/F Pack of 10$3.95 11 Jumper Wires Premium 6" F/F Pack of 10$3.95 11$18.50Power-Switch Tail 120 Kit for 110-120vac mains (PN PSTK-120) $18.50 21$19.00XBee Series 1 XB24-AWI-001XB24-AWI-001$38.00 Total188.37

38. 38 Department of Electrical and Computer Engineering Questions