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• Patrol the house via a 2D floor mapping algorithm• Detection of human skeleton• Alerts the user if an intruder is detected

PROJECT SPECIFIC SUCCESS CRITERIA (PSSC)1. An ability to control the speed and direction of a

robot2. An ability to automatically detect and avoid

obstacles3. An ability to capture and transmit live video from a

Kinect to a web server4. An ability to control the movement of the robot

through a web interface5. An ability to identify and respond to the detection

of a human

FUNCTIONAL BLOCK DIAGRAM

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

MAJOR COMPONENTS - MICRO SELECTIONPIC24FJ128GA006

• 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

MAJOR COMPONENTS - MOTHERBOARD REQUIREMENTS

• Three USB portso XBox Kinecto Flash Drive containing OSo 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)

MAJOR COMPONENTS - MOTHERBOARDIntel® 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

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

RENDERING OF PACKAGE DESIGN (FRONT)

RENDERING OF PACKAGE DESIGN (REAR)

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).

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.

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

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

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.

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)

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

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.

Debugging Circuit

• Reset Pushbutton• Debugging LED• RJ11 In-Circuit Debugger connection : pins

PGC1 and PGD1 • All microcontroller pins are padded out to

headers

Battery Schematic

• 3.3V regulator • Fuel Gauge IC

o 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:o two wire barrel connector providing unregulated

voltage from batteryo 4 wire bus ( .1" header ) providing the regulated

3.3V, and the two i2c signals.

Overall PCB Design Considerations

• Two separate PCBso Battery PCB - 3.3 volt regulator and fuel gaugeo Main PCB - microcontroller, power supplies, motor

driver, and sensors

• Power Supplies - 3.3, 5, 7.2, 12 volt supplieso All switching regulators that require careful layouto Wide traces to accommodate large amounts of

current

• Isolation of high current circuits from digital logico Microcontroller and analog sensors far from 12/7.2

volt power supplies and H-bridge circuit.

Overall PCB Design Considerations (cont.)• Pad out unused pins on microcontroller• Board space to accommodate external

connectorso Female RS232 - communication with Atomo 2 Barrel - Unregulated battery power and 12 volt output to

Kinect and Atom boardo Five 3 pin headers to IR sensors o Standard 0.1 inch headers for communication with other PCB,

optical encoders, motors, and unused microcontroller pinso RJ-11 connector for programming/debugging the PIC

microcontroller

• Main board smaller than 10"x10"

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

o At least 12 mil traces with 12 mil spacing for data lines

o Use 100 mil traces for power where possible.o Copper pours where there is space to reduce noise

produced by a circuit

• Locate decoupling capacitors as close to ICs as possible

Power Supplies - 12 Volt Supply

• LM25085 switching regulatoro 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

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

o Vias on the thermal pad to aid in heat dissipation

Power Suplies - 5 Volt / 3.3 Volt

• TPS62160 adjustable linear switching regulatoro resistor voltage divider determines output voltage

• Suggested layout in the datasheet

Microcontroller Layout

• Decoupling Capacitors on opposite side of microcontroller.

• Two row standard 0.1" spaced headers to pad out all pinso Debuggingo Unused pins

• RJ-11 header for PIC ICD 3 programming and debugging

• Reset button• Debugging LED

Battery PCB Layout

• Plenty of extra spaceo Used very wide traces and copper pours for high

current paths

• Ground plane

Software Design/Development Status

• Webservero Video Streaming - 90%o C&C Webpage - 0%

• Atom Boardo Kinect Depth Sensing - 60%o Point to Point Navigation - 20%o Map Building & Location Tracking - 10%

• Micro controllero Sensor Input - 80%o Motor Control - 0%o Tachometers - 0%o Fuel Gauge Communication - 0%

Software Design/Development Status

Software Design/Development Status

Timeline for Completion

Questions?