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					ECE 477 Final Presentation
   Group 2  Fall 2005
•   Project overview
•   Block diagram
•   Professional components
•   Design components
•   Success criteria demonstrations
•   Individual contributions
•   Project summary
•   Questions / discussion
Project Overview
• Trash Removing Autonomous Predator!
   – Keypad Controller with LCD output
   – Traverses a User-Defined Pickup Zone
   – Uses Digital Camera to Identify any kind of
     Empty Red Cans, Cups, etc…
   – Ultrasonic Sensor and Wheelbase Work
     Together to Maneuver Robot Into Position
     and Around Obstacles
   – Ultrasonic Sensor to Detect a
     “Basket Full” Condition
Block Diagram

FRONT             Servo                                     REAR
                 Motors x5
                                  4         1
Ultrasonic                                                 Ultrasonic
 Sensor                                                     Sensor
             2                                    2
                                      MCU              2
Camera                        8             6              Supply x2
                     Keypad                     H-Bridge
Professional Components
• Constraint analysis and component selection
• Patent liability analysis
• Reliability and safety analysis
• Ethical and environmental impact analysis
Constraint Analysis
• Microcontroller
  – Atmel AVR (Industrial)
  – SPI, UART and at least 30 general input
    output pins
  – Clock speed – due to the fact that most
    processing takes place while the robot is
    moving, it had to be fast enough to handle
    all peripherals while in motion
  – A minimum of 6 PWM channels
  – Sufficient number of timers/counters
Constraint Analysis
• Ultrasonic Sensors
  – Wide angle detection with a range of at
    least 1 meter
Constraint Analysis
• Scan Type Keypad (Spectra Symbol)
  – Small
  – Lightweight
Constraint Analysis
• LCD Display (Parallax Serial LCD)
   – Small
   – No backlight
   – Interface without the using the SPI (SPI
     already shared)
   – Consume as few I/O pins as possible
Constraint Analysis
• Camera CMUcam2+
  – Descent resolution, so that we can identify
    the boundaries of the colored object.
  – Ability to identify a colored object, based on
    its colors without any MCU image
    processing required.
  – Ability to shut the camera down from the
Constraint Analysis
• Compass module (Vector 2x)
  – 2 degree accuracy
  – ability to shut down when not used
  – ability to operate correctly under some
    mild electromagnetic interference
Constraint Analysis
• Shovel/Arm
  – Strong enough to be able to pick up the
    cans and to support its own weight
  – Weight must be as low as possible so that it
    doesn’t hinder the motorized base
  – Designed in such a way as to be able to pick
    up cans in most orientations
  – Aligned in such a way as it doesn’t get in the
    way of the sensors
Constraint Analysis
• Motorized base with basket
  – Strong enough motors to be able to carry
    the weight of the shovel and all the
  – Ability to rotate 360 degrees with the
    basket attached
• H-Bridge
  – Handle all four motors
  – Brake options
Constraint Analysis
• Batteries and Voltage regulation
  – At least two batteries, due to the large current
    requirement of the motors and the servos of
    the shovel
  – Voltage regulation to assure constant voltage
    for the microcontroller and peripherals
  – Efficient voltage regulation that won’t
    significantly affect the battery life
Component Selection Rationale
• Atmel ATMEGA128L usage
   – 8 MHz
   – 6 out of 8 PWM Modules (2 for H-Bridge, 4 for
     Shovel Servos)
   – 2 USART Modules (LCD and Camera)
   – 2 out of 8 ADC Modules (Battery Monitoring)
   – 1 out of 2 16-bit Timers (Ultrasonic Sensors x2)
   – SPI Module for Vector 2x Compass
   – 45 out of 53 I/O pins used
   – 0% EEPROM of 4Kb Used
   – 6.5% FLASH of 128Kb Used
Patent Liability Analysis
• Patent 6,941,199
  – Similarity
     • Moves autonomously over a surface
  – Difference
     • Uses collision detection to navigate
       instead of collision prevention
Patent Liability Analysis
• Patent 6,611,734
  – Similarities
     • Detects obstacles
     • Able to grip objects
  – Difference
     • Detects obstacles using infrared
       devices instead of ultrasonic sensor
     • Different gripping mechanism
Patent Liability Analysis
• Patent 5,935,179
  – Similarity
     • Uses ultrasonic devices for obstacle
  – Problem with designing around the patent
     • Using infrared sensors for obstacle
       detection is patented as well
  – Action required
     • Acquire license from patent
Reliability/Safety Analysis
• Reliability Analysis (MTTF analysis) Using
  MIL-HDBK-217F Military Handbook
  – Microprocessor Atmel ATMEGA 128L-8A –
    47.9 years
  – Servos Hitec HS 645MG – 182.6 years
  – Voltage Regulator LTC 1174-5 – 9 years
Reliability/Safety Analysis
• Safety Analysis using FMECA
  – High Criticality (Injury, Damage to Robot)
     • Erratic behavior of Shovel
     • Batteries catching fire
  – Low Criticality (Functionality Failure)
     • Power Supply Failure
     • Sensor Failure
     • Servo and Motor Failure
Ethical/Environmental Analysis
• Ethical
   – Operating Conditions:
      • Problem: Extreme weather conditions
                  (rain, sleet, snow, etc…)
      • Solution: Proper weatherproof casing
      • Problem: Proper lighting for camera
   – Physical Injury:
      • Problem: Sharp edges and pinch points from the arm;
                  numerous circuit boards
      • Solution: Plastic shovel as opposed to a metal one
      • Solution: Warning labels on circuit
                  boards, servo motors, shovel,
                  wheelbase and user manual
Ethical/Environmental Analysis
• Environmental – Bad
  – Six circuit boards
     • Lead, glass-epoxy, formaldehyde,
       copper foil, etc…
  – Two NiMH rechargeable batteries
  – Rubber wheels
  – Metal servo and wheel motors
  – Metal shovel
  – Plexiglas wheelbase casing
Ethical/Environmental Analysis
• Environmental – Good
   – Robot provides a positive impact on the
      • Picking up waste/recyclables
      • Reducing litter
   – Instructions in user manual for returning entire
     product at the end of its lifecycle
      • Recycle usable parts
      • Shipping reimbursement
        for consumer
Design Components
•   Packaging design considerations
•   Schematic design considerations
•   PCB layout design considerations
•   Software design considerations
Packaging Design

      Lynx Motion 4WD1 Base
Schematic Design
• Keypad
Schematic Design
• Voltage Regulator
Schematic Design
• ISP interface migration and SCK resistor
PCB Layout Design
PCB Layout Design
PCB Layout Design
PCB Layout Design
                    Fly Wire #1:
                    connected to
                    wrong pins of

                    NAND Gate
Software Design
• C Language using CodeVisionAVR
• Microcontroller Modules:
   – USART
      • LCD and Camera
   – SPI
      • Vector 2x Compass
   – PWM
      • Wheelbase and Servo Motors
   – Timers
      • Ultrasonic Sensors
   – ADC
      • Battery Monitoring
Software Design
• Polling Loop             Init

                    Check Keypad

                    Check Distance

                 Check Front Ultrasonic
Software Design
                           Initialization         Error


                               Main               Pause
                          (Polling Loop)


    PickUp            TrashID         Avoidance
Success Criteria Demonstrations
1. Ability to identify empty, red aluminum cans for
   pickup - demo
2. Ability to pick up identified object(s) - demo
3. Ability to automatically traverse the pickup zone, a
   rectangular grid - demo
4. Ability to detect a “basket full” condition - demo
5. Ability to set operation mode using a keypad and
   display system status using a LCD
   display - demo
Individual Contributions
•   Team Leader – Valentinos Zachariou
•   Team Member 2 – Jeffrey Alvin
•   Team Member 3 – Ricky Kannothra
•   Team Member 4 – Michael Dorsey
Team Leader – Valentinos Zachariou
•   Website Design
•   Component Research
•   Design Constraint Analysis
•   Purchased most of the components
•   Schematic and Theory of Operation
•   Package Design
•   Shovel Arm Design
•   Robot Construction
•   Helped with PCB Layout
•   Populated PCB
•   Helped with Software Design
Member 2 – Jeffrey Alvin
• Modules:
  – SPI Module
     • Compass
  – PWM Module
     • Servo
  – Ultrasonic Sensor
  – Keypad
• Packaging Specifications and Design Paper
• Patent Liability Analysis Paper
Member 3 – Ricky Kannothra
•   PCB Layout Design
•   Modules:
     – SPI Module
          • Compass
     – PWM Module
          • Shovel Servos
     – Timer/Counter Module
          • Ultrasonic Sensors
     – Keypad
     – ADC Module
          • Battery Monitoring
•   Software:
     – Basket Full
     – Trash Pickup
     – Repositioning
     – Avoidance
     – Check Battery
•   Reliability and Safety Analysis Report
Member 4 – Michael Dorsey
•   Modules:
     – USART Modules
         • Camera and LCD
     – SPI Module
         • Compass
     – PWM Module
         • Wheelbase
     – Keypad
•   Software:
     – Main Polling Loop
     – Initialization
     – Trash Pickup
     – Turnaround
     – Avoidance
     – Reposition
•   Ethical/Environmental Analysis
•   Software Design Considerations
Project Summary
• Important Lessons Learned
   – Know where you can get your components locally
   – Read component user manuals entirely
   – Sacrifice individual components for overall
   – Make wire connections that are properly insulated
   – Have backup components available
   – Make sure your package can easily be taken apart
     for corrections
   – Expect the unexpected
Project Summary
• Second iteration enhancements
   – Use wheel encoders to detect distance and
   – Use a turret for the camera
   – Better wheels (more durable)
   – Use Interrupt Driven Code
   – Use GPS for increased functionality (Larger
     Areas, e.g. football field)
   – Better weather shielding
   – Ability to identify a wider
     variety of trash
Questions / Discussion
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