Programmable MiniBlinds

1
Programmable Mini-Blinds

• Senior Design II
• Presented to Dr. Joe Picone
• April 29, 2004

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Team Members
3
Current Mini-blind Problems

• Hard for elderly / disabled people to operate
• Catch mechanism
• Wand
• Uneven lowering
• High window installations
• Strangulation hazards
• The wand breaks easily
• Appearance

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Programmable Mini-Blinds Adv.

• All blind movements are now automated
• Catch mechanism is eliminated
• Has controlled lowering
• Easily applied to all window heights
• No more dangerous cords and wands
• Cleaner appearance

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SDII - Major Design Constraints
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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Motor Design Issues 1st Semester

• Motor selection driven by size and holding
  torque
• Initial motor design required a direct torque
  output and required the use of a power off
  electronic brake to prevent power loss movement

Required Force to keep blinds stationary 10 lbs
3/8
Holding torque force x moment arm
10 lb x 3/16 in
30 oz-in
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1st Semester Motor Choice

• Lin Engineering 4118M-30
• 45 oz-in holding torque
• 1.8 step angle
• Size 42x42x40 mm
• 0.4 Amps/phase (13.24 VDC)
• Cost - 67.50 each
• Worm/worm gear combo
• 69 per motor
• Combination worked but was too expensive

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Motor Design Issues 2nd Semester

• Servo vs. Stepper???
• Worm/worm gear ratio investigated
• Motor speed control needed improvement
• Possibly reduce the voltage requirements
• Major cost reduction needed
• Motor shape investigated
• Motor placement studied

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Motor Design Issues 2nd Semester

• Motor selection driven by price, size, and
  holding torque

Required Force to keep blinds stationary 5 lbs
Holding torque force x moment arm
5 lb x 11/16 in
55 oz-in
11/8
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2nd Semester Motor Choice

• Danaher Motion 55M048D2U
• 14.5 oz-in holding torque
• 7.5 step angle
• Size 79x55x25.7mm
• 0.4 Amps/phase (12 VDC)
• Cost - 18.90 per motor
• Plastic worm/worm gear combo
• 12.62 total for both motors
• Round design makes for easier mounting

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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Motor Controller Update

• We decided to stick with the S100 motor
  controller
• Has preprogrammed instructions
• Separate power bus for motors
• Will fit in our blind housing without any
  modifications
• Has testing software

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Motor Controller Calculations

• Vertical speed prediction test
• Actual measured speed 0.3 in/sec
• Shading pps calculation

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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Lever Protective Switches

• Protects the motor from
• raising the blinds too far
• opening or closing the blinds too far
• SDII Fixed floating ground problem
• Also, used for automatic calibration

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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Chosen PIC for User Interface

• PIC 16F877A
• 33 I/O Pins (we use 16)
• Program Memory - 14.3Kb (we use 10.725 Kb)
• 368 Bytes of Data RAM (we use 92 Bytes)
• UART Serial Communication

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User Interface PIC Requirements

• Determine what instructions to send to motor
  controller
• Send instructions to the motor controller using
  RS232 communications protocol
• Store programmed actions set by user
• Interpret buttons that are pressed during
  movement or program mode

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MAX232

• Steps signals into and out of microprocessor to
  appropriate voltages.
• Main use communication between microcontroller
  and motor controller

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Software Design Section

• Power Saving Code
• Loops are used to contain different modes of
  operation
• Jumps are used to switch between modes

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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Power Supply and Bus Circuitry
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SDII Current Drain Slide
Our power supply outputs 1.0 A
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Hardware Component Diagram
Mini-Blinds Housing
User Interface Housing
Power Supply
PIC
Protective Switches
LEDs
Motor Controller
Interface Buttons
Bus Circuitry
Max 232
Motor 1
Motor 2
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Control Box
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PC Board Evolution
3.6 x 3.6
2.5 x 3.8
Decreased board size by 26.7
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Cost Analysis Comparison
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Houston Automated Shades MLS-40

• Automated but has no programmability in base
  model
• Their cost - 501.00
• Our cost - 202.08
• We offer more functionality at a lower cost!!!

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SDII vs. SD1 System Testing
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Design Constraints Check List
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Design Issues

• Worm/Worm gear alignment
• DOA motor
• Microcontroller port communications

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Our Design Before Motor DOA
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Acknowledgements

• Jesus Christ
• Dr. Herb Ginn
• Dr. Joe Picone
• Jonathan Heath
• Jordan Goulder
• Balaji Venkatesan

• William Brammer
• Mark Shorter
• Bill Buchanan
• Dr. Bob Reese
• Mr. David Tillman
• Mr. Bobby Sutton
• Dr. Bill Jones

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Any Questions
???
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References

• 1 Rod F. Wille, The Business Case for Building
  Green, Development, Winter 2003
• 2 U.S. Consumer Product Safety Commission,
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  Good Housekeeping, Oct2001, Vol. 233, Issue 4
• 4 For Rheumatoid Arthritis, Combination of
  Drugs is Best, Drug Week, March 2004.
• 5 Barbara Tunick, Joint Endeavor, Vegetarian
  Times, Issue 319, March 2004.
• 6 The Connecticut Department of Public Health,
  Arthritis at a Glance,http//www.dph.state.ct.us
  /BCH/HEI/arthritis20page.html
• 7 Holzhauer, CHOOSING AND SAFELY OPERATING
  POWERED HOISTS, Plant Engineering, Vol. 54,
  Issue 1, January 2000
• 8 Covington, QA, Electronics Now, Vol. 70,
  Issue 11, November 1999.
• 9 Equipment Reports, Electronics Now, Vol.
  65, Issue 8, August 1994.
• 10 Jack Dowell, Stepper Motors, Astronomy,
  Vol. 20, Issue 11, November 1992
• 11 Carl Becker, Todd Zalud, Packing Power into
  Worm Gears, Machine Design, Vol. 70, Issue 9,
  May 1998.
• 12 Paul Merrion, Put to the test, Crain's
  Chicago Business, Vol. 26, Issue 32, August 11,
  2003
• 13 Mark S. Birrttella, Robert R. Marley, Keith
  D. Nootbaar, Design Techniques for IC Voltage
  Regulators without p-n-p Transitors, IEEE
  Journal of Solid-State Circuits, Vol. SC-22,
  Issue 1, February 1987
• 14 PIC16F87XA Data Sheet, Microchip, October
  2003.
• 15 Max 232 Data Sheet, Dallas Semiconductor,
  November 2003.