programmable power relay mid-semester presentation
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Programmable Power Relay
Mid-semester presentation
Introduction
What’s the PPR supposed to do?• Control device power using schedule• Prevent schedule tampering• Minimize need for user input after schedule is
set
+
Problem
• Current power strips have few features
o No programmable timing scheduleo No interactive user interface
• Few methods to exercise parental control over electronic devices.
Solution
• "Smart" power strip with enhanced features
o Programmable Timing Schedule for AC-switchingo PC software application
• Parents will have ability to limit video game console use
• Automation and security are possible target markets
Technical Constraints
• Real Time Clocko Must operate at all times, under all power
conditions • Timing Schedule Accuracy
o Must include Years, Months, Days, Hours, Minutes, Seconds
• User Interfaceo PC is required to operate
• Internal Power Supplyo Must supply power to internals from 120VAC
• Switching Power Rating o Must operate up to 120VAC at 15A (NEMA 5-15
Standard) [1]
Practical Constraints
Health and Safety
• Must conform to Underwriters Laboratories (UL) standards for safetyo UL 758 standard for appliance wiring materialo Within the UL 758
Construction Performance Thermal and Chemical property tests Electrical and Flame properties Manufacturing Labeling Production
[2]
Economic
• Must be manufactured for less than $50o Retail at ~$100o Comparable products retail from $40 to $90o Must be able to compete at a reasonable price
[3], [4]
Isolé® IDP-3050 Plug Load Control
Smart Strip Power Strip
Technical Approach
User Interface
Approach Pros Cons
Computer Based Programming Software
Cheap Easy to navigate Upgradeable
Requires programming cable
Onboard LCD and Keypad
Independent Limited resolution Requires additional power Expensive
Battery BackupApproach Pros ConsLTC690 μProcessor Supervisor IC
Effective battery
switchover during loss
of primary power.
Low current pass-through rating Unnecessary features Powers entire μProcessor on
battery backup
TPS2111 Power Multiplexer IC
High current pass-through (1A).
Powers entire μProcessor on
battery backup Relies on voltage thresholds
when switching between power
supplies
DS1307 - Real Time Clock Calendar IC
Built in low power draw
battery backup dock Only powers RTCC IC
Redundant design
Microprocessor
Approach Pros ConsPIC24FJ64GA002 Inexpensive
Onboard Real Time Clock and
Calendar
Unneeded features No method for powering just the
RTCC off of a battery backup. Inefficient - 4.1mA at 3.3v running at
4Mhz
PIC18F2420 Streamline features Small device footprint Efficient - 1.3mA at 3.3v running
at 4MhZ
Expensive
Power Switching
Approach Pros ConsBTA140-600 TRIAC Solid State
Inexpensive Small footprint
Requires a heatsink Requires optoisolator
T90N5D12 Relay Simple installation Expensive Noisy Large
Power Supply
Approach Pros ConsTransformer + Diode Bridge combination
Proven design Multiple parts Weight Expensive
BP5063-5 AC/DC Converter
Compact package Inexpensive
ScheduleDate Deliverables Project
9/8 Problem Statement - Final Order Parts - PIC(s), USB-to-RS232, TRIAC
9/15 Design Constraint - DraftParts Arrive - Start Breadboarding. Design test program to cycle hardware.
9/22 Design Constraint - FinalExtended Breadboarding/Prototyping. Begin Schematic design
9/29 Midterm Presentations Continue working on hardware prototype
10/6 Midterm Presentations Continue working on hardware prototype
10/13 TBA Finalize Hardware
10/20 TBADevelop software breakdown and begin coding PC software interface
10/28Progress Review / Approach Draft Continue software development
11/3 Approach - Final Finish software
11/10Executive Summary Overview - Draft Debugging
11/17 Evaluation - Draft Debugging
11/24 TBA Debugging
12/1 TBA Final Project due
References
[1] Powercords Online, "IDC Plugs - Standards," [Online]. Availible http://www.powercords.co.uk/standard.htm [2] "Appliance Wiring Material, UL 758." Underwriters Laboratories. http://ulstandardsinfonet.ul.com/scopes/0758.html. Accessed September 16, 2008. [3] “Isolé® IDP-3050 Plug Load Control.” WattStopper. http://www.wattstopper.com/products/details.html?id=74&category=122&type=Commercial. Accessed August 27, 2008. [4] “Bits Energy Saving Smart Strips.” Bits Limited. http://catalog.bitsltd.us/power_strips/. Accessed August 27, 2008.
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