Personal Power Consumption Analyst
Senior Design I: Dr. Randolph Follett
Spencer Gass
John Barr
Grant Patrick Abbey
Spencer Gass, EE (Team Lead)
Website Design
Software Application
» Bluetooth/Mobile Application
John Barr, EE
Website Updates
Hardware
» High Voltage Application
Grant Abbey, EE
Software Application
Hardware
» Hardware Communication
Associate Professor
» Ph.D., Electrical Engineering, Energy Systems,
University of Toronto, Canada, 2004
Academic/Research and Fields of Interest:
» Phase-locked loop and nonlinear filtering
techniques for power engineering applications
» Optimal/Robust/Nonlinear controls for distributed
and renewable energy systems, and hybrid
renewable energy systems
» Phasor measurement for wide area applications
» Power quality measurement and enhancement
» Estimation of power system variables/parameters
» Power system stability, protection and control
» Problem
» Solution Overview
» Design Constraints
˃ Technical/Practical Constraints
» Solution Details
˃ Sensing
˃ Communications/Processing
˃ Mobile Application
» Progress
» Work Plan Schedule
» Electricity usage is expensive.
» However, many people are unaware of exactly how much power
is used by any given device in their home.
» Is there a way to measure how much power is consumed by any
household device?
» Current market solutions
˃ Instantaneous measurements
˃ Displays on meter itself
» SmartMeter focuses more on Power Trend Analysis rather than a
simple instantaneous value.
˃ Informative software interfaces
˃ Consumption during operation, sleep, hibernation, and wake-up cycles
˃ Graphs of consumption over time (hours, days, weeks)
» Govern how the product must perform its tasks
» Identify technical specifications
» Govern physical object itself
» Ensure the product is a practical choice for its task
Constraint
Description
Current Rating
The product must be able to supply an amount equal to or greater than an
average 110V or 220V plug can supply - 20A, 40A, respectively.
Accuracy
Power measurement data should be accurate within ±5%.
Sampling Rate
Measurements are sampled at a minimum of 3,900 samples per second.
Data Storage Space
The product must have onboard storage space sufficient for 24 hours of data
storage in case of lost connection with the appliance.
Transmission Range
Transmission of data to the interfacing device should be possible over 32 feet
(9.75m) assuming standard household furniture in the line of sight.
» Market
˃ High-end market quality
˃ Competitive pricing
» Lasting value
˃ Able to pay for itself
˃ Must not over-consume power
 $30 Retail
» Personal Safety
˃ Electrocution
» Fire Hazard
˃ Arcing to outside materials
˃ Arcing within circuitry
Home Outlet
(120VAC)
Mobile
App
(QT)
LOAD
Current Sensing
Voltage Scaling
Sensing
Power
Measurement
SPI
Communication
Processing
(Microcontroller)
Wireless Relay to
Application
Bluetooth Module
UART
Communication
» Current Sensor (Allegro ACS712)
˃ 30A Hall-effect sensor
˃ (66mV/A + Vcc/2) analog voltage output [1]
» Load Test
˃ Connected 0.5A load – Expected 2.508V output
˃ Verified Output Readings vs. Multimeter
˃ Accuracy within 1.1%
» Voltage Sensor (R/C Circuit)
˃ Inexpensive 10.27MΩ resistor series, output voltage over 270kΩ resistor
» Basic Voltage Measurement Test
˃ Connect to Wall Outlet (≈120V)
˃ Verify output Voltage with Multimeter
» STPM01 (ST Microelectronics)
˃ Digital active, reactive, apparent power readings
˃ 0.1% rated accuracy [2]
˃ SPI Communication between chip and microprocessor
» Communication (SPI) Test
˃ Connect chip and microprocessor and verify data
transaction
» PIC24 Microprocessor (Quick Fix)
˃ Receive output from sensing networks
˃ Basic active power calculations
» Measurement Test
˃ Instruct chip to compute active power given voltage and
current
˃ Print calculations to screen
» PIC24 Microprocessor
˃ High-performance, 16-bit [3]
˃ C compiler
˃ Experience within team and favored by professors
» Output Test
˃ Read power measurements
˃ Print raw data for verification
» PIC24 → Bluetooth Module
Bluetooth Module
˃ Used in communication between PIC and
Bluetooth module
» Communication Test
˃ Receive Transmit echo
˃ Observe with logic analyzer
Processing
(PIC24)
UART
Communication
Mobile
App
(QT)
» BlueSMiRF Silver Bluetooth Module
˃ Lower Power
˃ Claims 66ft (20m) transmission range [4]
» Transmission Range Test
˃
˃
˃
˃
˃
Recall: At least 32ft transmission constraint
Paired mobile application with BlueSMiRF
Increased distance between devices
Checked connection strength
At 100ft separation, connection was still maintained
Wireless Relay to
Application
[5]
» QT Development
˃ Bluetooth Libraries
˃ GUI Support
˃ Android app
» Plot Test
˃ Powered Soldering Iron through SmartMeter
˃ Transmit power measurements
˃ Verify that data reception and plot
Section
Component
Hardware
Current Sensor
Power Measurement IC
Voltage Scaling Network
Microprocessor
Software
Bluetooth Module
SPI Communication
UART Interfacing
Mobile Application
Acquired
Testing
Confirmed
Integrated
August
Research - All
Part Selection - All
Circuit Design – Grant, John
Software – Spencer, Grant
System Integration - All
Testing – All
September
October
November
»
»
»
»
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[1] Allegro Microsystems, “Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1kVRMS Isolation and a LowResistance Current Conductor,” ACS712 datasheet, 2006 [Revised Nov. 2012].
[2] ST Microelectronics, “Programmable single phase energy metering IC with tamper detection,” STPM01 datasheet, Jun. 2011
[Revised Jun. 2011].
[3] Microchip Technology, “PIC24HJ32GP202/204 and PIC24HJ16GP304 Data Sheet,” PIC24 datasheet, May 2007 [Revised Aug.
2007].
[4] "RN-42 Datasheet" [Online]. Available: http://cdn.sparkfun.com/datasheets/Wireless/Bluetooth/Bluetooth-RN-42-DS.pdf
[Accessed October 16, 2015].
[5] SparkFun Bluetooth Modem - BlueSMiRF Silver”[Online]. Available: https://www.sparkfun.com/products/12577