Presentation on theme: "ECE 477 Design Review Team 16 Neil Kumar, Scott Stack, Jon Roose, John Hubberts."— Presentation transcript:
ECE 477 Design Review Team 16 Neil Kumar, Scott Stack, Jon Roose, John Hubberts
P ROJECT O VERVIEW 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
P ROJECT S PECIFIC S UCCESS C RITERIA (PSSC) 1. An ability to control the speed and direction of a robot 2. An ability to automatically detect and avoid obstacles 3. An ability to capture and transmit live video from a Kinect to a web server 4. An ability to control the movement of the robot through a web interface 5. An ability to identify and respond to the detection of a human
M AJOR C OMPONENTS - M ICRO R EQUIREMENTS 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
M AJOR C OMPONENTS - M ICRO S ELECTION 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
M AJOR C OMPONENTS - M OTHERBOARD R EQUIREMENTS Three USB ports o XBox Kinect o Flash Drive containing OS o 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)
M AJOR C OMPONENTS - M OTHERBOARD 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
P ACKAGING C ONSTRAINTS 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
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 battery o 4 wire bus (.1" header ) providing the regulated 3.3V, and the two i2c signals.
Overall PCB Design Considerations Two separate PCBs o Battery PCB - 3.3 volt regulator and fuel gauge o Main PCB - microcontroller, power supplies, motor driver, and sensors Power Supplies - 3.3, 5, 7.2, 12 volt supplies o All switching regulators that require careful layout o Wide traces to accommodate large amounts of current Isolation of high current circuits from digital logic o 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 connectors o Female RS232 - communication with Atom o 2 Barrel - Unregulated battery power and 12 volt output to Kinect and Atom board o Five 3 pin headers to IR sensors o Standard 0.1 inch headers for communication with other PCB, optical encoders, motors, and unused microcontroller pins o 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 regulator o 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 regulator o 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 pins o Debugging o Unused pins RJ-11 header for PIC ICD 3 programming and debugging Reset button Debugging LED
Battery PCB Layout Plenty of extra space o Used very wide traces and copper pours for high current paths Ground plane
Webserver o Video Streaming - 90% o C&C Webpage - 0% Atom Board o Kinect Depth Sensing - 60% o Point to Point Navigation - 20% o Map Building & Location Tracking - 10% Micro controller o Sensor Input - 80% o Motor Control - 0% o Tachometers - 0% o Fuel Gauge Communication - 0% Software Design/Development Status