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ECE 477 Design Review Team 16

ECE 477 Design Review Team 16. Neil Kumar, Scott Stack, Jon Roose, John Hubberts. Project Overview. Home security robot 2 Modes of operation Manual Control Go to a website and drive the robot Live Color or Infrared video feeds Autonomous sentry mode

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ECE 477 Design Review Team 16

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  1. ECE 477 Design Review Team 16 Neil Kumar, Scott Stack, Jon Roose, John Hubberts

  2. Project Overview • Home security robot • 2 Modes of operation • Manual Control • Go to a website and drive the robot • Live Color or Infrared video feeds • Autonomous sentry mode • Patrol the house via a 2D floor mapping algorithm • Detection of human skeleton • Alerts the user if an intruder is detected

  3. Project Specific Success Criteria (PSSC) • An ability to control the speed and direction of a robot • An ability to automatically detect and avoid obstacles • An ability to capture and transmit live video from a Kinect to a web server • An ability to control the movement of the robot through a web interface • An ability to identify and respond to the detection of a human

  4. Functional Block Diagram

  5. Major Components - Micro Requirements • 5 A/D channels for IR sensors • 2 PWM channels for motors • 1 UART interface for communication with ATOM board through RS232 • 1 I2C module for communication with fuel gauge on battery PCB • 4 GPIO channels for H-bridges • 2 Input Capture channels for tachometers

  6. Major Components - Micro Selection PIC24FJ128GA006 • 16 A/D channels • 5 PWM channels • 2 UART modules • 2 I2C interfaces • 8MHz internal oscillator • 64 pin TQFP package • Operating Voltage 2.0V-3.6V

  7. Major Components - Motherboard Requirements • Three USB ports • XBox Kinect • Flash Drive containing OS • WiFi adaptor • RS-232 Module for communication with microcontroller • High speed, preferably dual-core processor (for real time encoding of Kinect camera data) • Relatively low power consumption for the sake of battery life (<40W preferred)

  8. Major Components - Motherboard Intel® Desktop Board DN2800MT • Eight USB 2.0 Ports (4 External, 4 Internal) • Two RS232 Serial Connection Port • Intel® Atom Processor N2800 • 1M Cache, 1.86GHz Dual Core • Fanless cooling system • Minimum Power Consumption 24.5W

  9. Packaging Constraints • Needs to be able to navigate indoor terrain • Needs to be able to support 10lbs of electronic equipment • Needs to be short enough to turn around in relatively narrow hallways (~5ft wide) • Needs to be built in a way that prevents Kinect from 'seeing' parts of the chassis

  10. Rendering of Package Design (Front)

  11. Rendering of Package Design (Rear)

  12. Schematic constraints • Control direction and speed of 2 motors (PWM/GPIO) • Read in data from 5 IR sensors (ADC) • Read in fuel level from fuel gauge (i2c) • communicate control/sensor data to/from Atom (UART - RS232) • requires 4 regulated voltage levels (12V, 7.2V, 5V, 3.3V).

  13. Design Considerations • We will not have a re-charging IC integrated into our design. Thus, the battery will have to be removed and charged with a commercially available charger. • The Fuel Gauge we are using is required to be attached to the battery during charging and discharging in order to maintain accuracy. • As a result of both of these factors we will be using 2 separate PCB's • Use Decoupling capacitors reduce power noise • Try to separate modules physically from each other on microcontroller.

  14. Microcontroller Schematic • 5 ADC Sensors • RS232 level converter and COM port • 12V, 7.2V, 5V regulators • H-Bridge and motor control circuit • Input Capture (tachometer) • i2c circuit • Debugging Circuit

  15. ADC • 5 pins from microcontroller padded to headers for sensors. • IR sensors return 10-bit value to microcontroller • Use analog reference voltage of 5V • Pins Used: AN9,AN5, AN4, AN3, AN2

  16. RS232 Level converter and COM port • Microcontroller has to send sensor data and receive control data from the Intel Atom • Micro will accomplish this using its UART module via RS232 (pins: U1RX, U1TX) • These signals must be converted from 3.3V to 5V before passing through a RS232 (MAX233) Level converter and to a COM port.

  17. H-Bridge Motor Control Circuit • Two 16-bit PWM pins (OC2, OC3) used to control speed of two motors • 4 GPIO pins (RE4, RE3, RE2, RE1) used to control direction of motors through the H-Bridge • All six signals are converted from 3.3V to 5V logic using the TXB0108, a bi-directional digital logic converter. • The motors require 7.2 V input at up to 4 Amps, H-Bridge (L298) draws regulated 7.2V to power motors. • requires inductive kickback diodes that can handle up to 1000V ~ 2A (max)

  18. Input Capture • Tachometer provides 90 pulses for every rotation of motor • calculates pulses based on integrated IR sensor and light. • Used to measure time between pulses from the tachometer to calculate speed and distance traveled. • Uses pins IC3 and IC4

  19. i2c Circuit • We will only have one device using the i2c module, the fuel gauge IC (BQ34Z100). • Since the micro and the fuel gauge are on separate boards the SDA/SCL lines will be padded out to headers on both boards and connected via a two wire cable.

  20. Debugging Circuit • Reset Pushbutton • Debugging LED • RJ11 In-Circuit Debugger connection : pins PGC1 and PGD1 • All microcontroller pins are padded out to headers

  21. Battery Schematic • 3.3V regulator • Fuel Gauge IC • measures the current from the battery using a .012 ohm current sensing resistor, the resistor value that we chose is based on equations from the datasheet. • Both boards will be connected by two cables: • two wire barrel connector providing unregulated voltage from battery • 4 wire bus ( .1" header ) providing the regulated 3.3V, and the two i2c signals.

  22. Overall PCB Design Considerations • Two separate PCBs • Battery PCB - 3.3 volt regulator and fuel gauge • Main PCB - microcontroller, power supplies, motor driver, and sensors • Power Supplies - 3.3, 5, 7.2, 12 volt supplies • All switching regulators that require careful layout • Wide traces to accommodate large amounts of current • Isolation of high current circuits from digital logic • Microcontroller and analog sensors far from 12/7.2 volt power supplies and H-bridge circuit.

  23. Overall PCB Design Considerations (cont.) • Pad out unused pins on microcontroller • Board space to accommodate external connectors • Female RS232 - communication with Atom • 2 Barrel - Unregulated battery power and 12 volt output to Kinect and Atom board • Five 3 pin headers to IR sensors • Standard 0.1 inch headers for communication with other PCB, optical encoders, motors, and unused microcontroller pins • RJ-11 connector for programming/debugging the PIC microcontroller • Main board smaller than 10"x10"

  24. Overall PCB Design Considerations (cont.) • Battery PCB smaller than 3.5"x3.5" • No acute angles in traces or pours • No right angles in data traces • Trace widths • At least 12 mil traces with 12 mil spacing for data lines • Use 100 mil traces for power where possible. • Copper pours where there is space to reduce noise produced by a circuit • Locate decoupling capacitors as close to ICs as possible

  25. Power Supplies - 12 Volt Supply • LM25085 switching regulator • Most external components of all sources • Locate components as close to IC pins as possible. • Minimize the length of key current loops • Use wide traces and copper pours

  26. Power Supplies - 7.2 Volt Supply • TPS5450-Q1 switching regulator • Locate components as close to IC pins as possible. • Use wide traces and copper pours • Thermal pad under IC for heat dissipation • Vias on the thermal pad to aid in heat dissipation

  27. Power Suplies - 5 Volt / 3.3 Volt • TPS62160 adjustable linear switching regulator • resistor voltage divider determines output voltage • Suggested layout in the datasheet

  28. Microcontroller Layout • Decoupling Capacitors on opposite side of microcontroller. • Two row standard 0.1" spaced headers to pad out all pins • Debugging • Unused pins • RJ-11 header for PIC ICD 3 programming and debugging • Reset button • Debugging LED

  29. Battery PCB Layout • Plenty of extra space • Used very wide traces and copper pours for high current paths • Ground plane

  30. Software Design/Development Status

  31. Software Design/Development Status • Webserver • Video Streaming - 90% • C&C Webpage - 0% • Atom Board • Kinect Depth Sensing - 60% • Point to Point Navigation - 20% • Map Building & Location Tracking - 10% • Micro controller • Sensor Input - 80% • Motor Control - 0% • Tachometers - 0% • Fuel Gauge Communication - 0%

  32. Software Design/Development Status

  33. Timeline for Completion

  34. Questions?

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