SmartMeterSenior Design I: Dr. Randolph Follett

Spencer GassJohn Barr

Grant Patrick Abbey

Personal Power Consumption Analyst

Team Gass

John Barr, EEWebsite UpdatesHardware» High Voltage Application

Spencer Gass, EE (Team Lead)Website DesignSoftware Application» Bluetooth/Mobile Application

Grant Abbey, EESoftware ApplicationHardware» Hardware Communication

Faculty Adviser

Dr. Masoud KarimiAssociate 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

Content

» Problem» Solution Overview» Design Constraints

˃ Technical/Practical Constraints

» Solution Details˃ Sensing˃ Communications/Processing˃ Mobile Application

» Progress» Work Plan Schedule

Problem

» 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?

Solution Overview

» 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)

Constraining Factors

Technical Constraints» Govern how the product must perform its tasks» Identify technical specifications

Practical Constraints» Govern physical object itself» Ensure the product is a practical choice for its task

Technical Constraints

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.

Practical Constraints

Economic» Market

˃ High-end market quality˃ Competitive pricing

» Lasting value˃ Able to pay for itself˃ Must not over-consume power

$30 Retail

Safety» Personal Safety

˃ Electrocution

» Fire Hazard˃ Arcing to outside materials˃ Arcing within circuitry

Solution Details

LOADHome Outlet(120VAC) Current Sensing

Power Measurement

Processing (Microcontroller)

MobileApp (QT)

Subsets

Voltage Scaling

Sensing

SPI Communication

Bluetooth Module

UART Communication

Wireless Relay to Application

Subset Testing

Sensing: Current Sensing» 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%

Subset Testing

Sensing: Voltage Scaling» 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 120V Outlet

(Hot Leg)

100MΩ

Vout

270kΩ

Subset Testing

Sensing: Power Measurement» 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

Subset Testing

Sensing: Power Measurement» 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

Subset Testing

Processing» 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

UART Communication» PIC24 → Bluetooth Module

˃ Used in communication between PIC and Bluetooth module

» Communication Test˃ Receive Transmit echo˃ Observe with logic analyzer

Subset Testing

Processing (PIC24)

Bluetooth Module

UART Communication

Wireless Relay to Application» 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

Subset Testing

MobileApp (QT)

Wireless Relay to Application

[5]

Mobile Application» QT Development

˃ Bluetooth Libraries˃ GUI Support˃ Android app

» Plot Test˃ Powered Soldering Iron through SmartMeter˃ Transmit power measurements˃ Verify that data reception and plot

Subset Testing

Progress

Section Component Acquired Testing Confirmed Integrated

Hardware

Current Sensor

Power Measurement IC

Voltage Scaling Network

Microprocessor

Bluetooth Module

Software

SPI Communication

UART Interfacing

Mobile Application

Expected Timeline

August September October November

Research - All

Part Selection - All

Circuit Design – Grant, John

Software – Spencer, Grant

System Integration - All

Testing – All

Questions?

Works Cited

» [1] Allegro Microsystems, “Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1kVRMS Isolation and a Low-Resistance 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