Project “RedEye”

University of Central FloridaCollege of Electrical Engineering and Computer Science

Senior Design Fall 2011

Group 8David Morrow

Ricardo RodriguezShane Theobald

Nick Bauer

Wanted to gain experience in many different engineering disciplines◦ C# - GUI◦ Optics – Laser Range Finder◦ Wireless Communication◦ Controlling Peripheral Devices via Microcontroller

Motivation

Goals Calculate the GPS coordinates of a user

specified target using the following components.◦ Wireless Camera◦ Laser Rangefinder◦ Digital Compass◦ GPS Module

Minimize◦ Cost◦ Weight◦ Power Consumption

Target Specs◦ 50m minimum distance◦ 1000m maximum distance◦ 10m x 10m minimum target size

Accuracy◦ Rangefinder distance within ±10m◦ Self GPS coordinates within 5m radius of true

location◦ Compass heading within ±1° of true heading◦ Final target GPS coordinates within 50m radius of

true location

Project Specifications

Block Diagram

Operational Flow Chart

Methods of Laser Rangefinding◦ Triangulation

Easiest method both conceptually and design Based on geometry Increasingly less accurate as range increases

◦ Interferometry Most accurate method of laser rangefinding Can measure small distances on order of

wavelengths◦ Time-of-flight

Can measure very large distances with great accuracy

This is the approach that we will implement

Rangefinder Subsystem

Time-of-Flight Rangefinder

Photodetector HV Power Supply Front End Amplifier (Transimpedance Amp) NIR optical filter Receiver Lens

Receiver Module Components

Pros◦ Highly Sensitive Photodetectors◦ Make use of avalanche multiplication for

increased gain◦ High Speed◦ Designed for rangefinder applications◦ Allows for larger maximum range detection

Cons◦ Require HV reverse bias to get maximum gain◦ Exhibit higher dark current than alternatives◦ Small active area makes alignment difficult

Avalanche Photodiode (Detector)

APD Design Characteristics

Peak Spectral Response Cost and Availability Minimum Dark Current Required Bias Voltage

Pacific Silicon AD230-9 Enhanced for NIR detection at 900nm

Low noise equivalent power = 10fW/√Hz TO-52 Package allows for easy mounting

Spectral Response at M = 100

HV Power Supply—EMCO A025P Proportional Input/Output Voltage 250VDC when full 5V input applied Low peak-to-peak ripple (<1%) Maximum Output Current 4mA Low turn on voltage of 0.7V

Converts photocurrent into voltage High Slew Rate at 290V/µs Low Input Noise Voltage 7nV/√HZ FREE—Sampled

Transimpedance AmplifierTI OPA656

Receiver System Schematic

Optical Bandpass Filter

860 870 880 890 900 910 920 930 940 9500

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Wavelenth in nm

Tran

smis

sion

Filter Specs◦ 2 in X 2in X .1in◦ CWL 905.9nm◦ BBW 54.0nm◦ Peak transmission

79%

Receiver Prototype Overview

Receiver Electronics

Lens Tube Assembly

Power Received

Prec =Ptx e(-αRtx) ρ e(- αRrx) Arx Topt

πRrx2

Threshold Detection

Prevent False Alarms◦ Capture as much energy as possible◦ Keep noise floor low◦ Set threshold

Output Power—Need high power laser diode to meet maximum range criterion

Pulsewidth—Must have short pulsewidth to have high axial (range) resolution (V x τp)

Wavelength—Transmitter near peak responsivity of photodetector.

Beam Divergence—low divergence angle to ensure maximum energy on target

Laser Transmitter Design Parameters

Laser Diode Options

HA!

Laser Diode SPL-PL-90_3

◦ TO-18 Package◦ Divergence 9 x 25 gradient degrees◦ Minimum Rise/Fall time 1ns◦ Threshold Current 0.75A◦ Peak wavelength 905nm◦ Power output 75W◦ Peak Current 40A◦ Typical Voltage 9V◦ Pulsewidth 5-100ns

5.9mm

5mm

Pros◦ Very small in size at 1”x2.5”◦ Produces fixed pulsewidth at 15ns◦ Can produce up to 50A diode drive current◦ Diode mounts easily to CCA. (Radial or Axial

options) Cons

◦ Also requires high voltage source◦ 33ns propagation delay◦ Difficult T-zero capture

Diode Driver CCAIXYS PCO 7110-50-15

Supply Current◦ Ips = (Cpfn + Cfet + Cstray) * Vin * f◦ Ips = (4000pF + 120pF + 430pF) *195V *1Hz

=0.9µA Output Current

◦ Directly dependent on HV supply (195V is max)

Diode Driver continued

JP1 Connection

Diode Driver Continued

Pin 1 GroundPin 2 15V @ 1mA (support power)Pin 3 GroundPin 4 Gate (Trigger) 5VPin 5 Ground

Pin 10 HV in (0 - 195V @ Ips)

Laser Transmitter Diagram

Transmitter Prototype Overview

Transmitter Electronics

High Voltage◦ Diode Driver Board – 195Vmax◦ Avalanche Photodiode – 240V

15V◦ Diode Driver Board

10-13V◦ Camera System

±5V◦ Comparator◦ Op Amps

5V◦ High Voltage Power Supply

3.3V◦ Microprocessor◦ TDC

Voltage Requirements

Power Supply Overview

TDC: ACAM GP2-G590 Creates a digital value for the laser pulses

time of flight from the transmitter to the receiver.◦ 2 channels with 50 ps rms resolution◦ Measurement from 3.5ns to 1.8ms◦ Fire pulse generator◦ I/O voltage 1.8v – 5.5v◦ Core voltage 1.8 – 3.6v◦ 4 wire SPI interface◦ QFN 32 Package 5mm

5mm

Microcontroller◦ Programming Language: C◦ Development Environment: Arduino Uno IDE◦ Handles data collection and peripheral control

GUI◦ Programming Language: C#◦ Development Environment: MS Visual Studio◦ Receives user input and displays relevant

information

Software Design

Embedded Overview

MCUXBee TDC

Pan & Tilt

GPS Compass

MCU: ATmega328Clock Speed

Core SizeI/O Pins

Package SizeMemory

UART/I2C/SPI/PMWOperating Voltage

Price

16 MHz8 bit14DIP 2832 kB2 / 1 / 2 / 61.8 – 5.5V$6.27

• Mounted on Arduino development board• Arduino Uno development environment compatibility

• C Programming language• Allows for flexible troubleshooting • Large support community• SPI, I2C, & Serial libraries

IDE: Arduino Uno

GPS: EM-406A SiRF III 

Input VoltageInput Current

Baud RateC/A code

Comm. ProtocolAccuracy

Price

4.5 – 6.5V 44 mA48001.023 MHzUART; RS-2325m WAAS$59.95

5cm

5cm

Compass: HMC6352

Input VoltageInput Current

Field RangeResolution

Comm. ProtocolWeight

Price

2.7 – 3V2 – 10mA0.1 gauss0.5 degreesI2C0.14 grams$34.95

• Two axis digital compass• Provides heading in degrees

from magnetic north

100ft radial distance Omni-directional link Low Power Consumption

Wireless Comm: Overview

Wireless Comm: XBee Series 2

Input VoltageRX/TX Current

Transmit PowerTX SensitivityRF Data Rate

Baud RateFrequency Band

Indoor RangeOutdoor Range

ProtocolAntenna

Price

2.8 – 3.6V40 mA2 mW (+3 dBm)-98 dBm250 Kbps1200 – 1 Mbps2.4 GHz133ft400ftZigbee (802.15.4)Whip (dipole)$25.95 (X2)

3cm

3cm

Servos: Hitec HS-485HBOperating Voltage

Operating Speed (6V)Stall Torque

Operating AngleCurrent Drain (6V)

Motor TypeWeight

Price

4.8 – 6V.18 sec/600

83.3 oz/in450

8.8 mA / 180 mA3 Pole Ferrite1.59 oz$16.99

Pan & Tilt: Hitec SPT200Weight (w/o servos)

Tilt SwingMax. Payload

Price

5.5 oz135o

2 lbs$45.99

Schematic Overview

1/3” Sony CCD microboard camera◦ NTSC format◦ 510x492 pixels

900MHz Tx/Rx combo

Camera and Tx/Rx

GUI Functional Flow Diagram

Open GUI

Connect to XBee

and Video

Poll GPS

Poll Compass

Display Info

User Input

Move Camera

Fire Laser

no yes

GUI - UML Diagram

PositionalData

- double CompassHeading

- double latitude

- string LatitudeHeading

- double longitude

- string LongitudeHeading

RangeFinder

+ PositionalData Info

+ int distance

- PollGPS()- PollCompass()

- PollLaser()

- DisplayData()

Target

+ PositionalData targetData

+ RangeFinder rangefinderData

- CalculateGPS()- DisplayData()

GUI – Prototype Layout

Given:◦ Self GPS Coordinates

Latitude (N/S ddmm.mmmm) Longitude (E/W ddmm.mmmm)

◦ Distance to target (m)◦ Heading clockwise from magnetic north (deg)

Calculate:◦ Target GPS Coordinates

Latitude (N/S ddmm.mmmm) Longitude (E/W ddmm.mmmm)

Target GPS Algorithm

Spherical Law of Cosines

◦ Self GPS coordinates (lat1, lon1)◦ Distance to target (d)◦ Heading (Θ)◦ Radius of the earth (R)◦ Target GPS coordinates (lat2, lon2)

[ ]lat2 = sin-1[ sin(lat1)*cos(d/R) + cos(lat1)*sin(d/R)*cos(Θ) ]

lon2 = lon1 + tan-12 cos(lat1)*sin(d/R)*sin(Θ) cos(d/R) - sin(lat1)*sin(lat2)

Target GPS Algorithm – cont.

Budget

Quantity Part Name Cost Total2 Laser Diode OSRAM SPL PL 90_3 $55.00 $110.001 Diode Driver IXYS PCO 7110-50-15 $207.20 $207.201 APD Pacific Silicon AD230-9 TO52-S1 $92.53 $92.531 Optical Band Pass Filter $30.00 $30.001 Laser Diode Collimation Tube $15.00 $15.001 Receiver Extension Tube $140.00 $140.001 Receiver Lens $34.00 $34.002 HV Power Supply EMCO A025 $65.78 $131.561 Op-Amp TI OPA656 $0.00 $0.001 Assorted Resistors/Capacitors $10.00 $10.00

Rangefinder Components

Subsystem Cost Analysis BudgetLaser System $770.29 $850.00Time to Digital Conversion $35.00 $50.00Camera System $0.00 $100.00Compass Module $35.00 $50.00GPS Module $79.99 $100.00Wireless System $50.00 $100.00Microcontroller $31.27 $50.00Power System $0.00 $25.00Mounting Fixture and Servo Motors $0.00 $100.00PCB Construction $0.00 $75.00

TOTALS: $1,001.55 $1,500.00

Responsibility Matrix – Phase 1PHASE 1 - Components 21%GPS 38%

Microcontroller Communication 4-Sep X 25%Data Manipulation in GUI 4-Sep X 50%

Compass 38%Microcontroller Communication 11-Sep X 25%Data Manipulation in GUI 11-Sep X 50%

Camera 17%Wireless Communication 18-Sep X 0%Video in GUI 18-Sep X 50%Optics 18-Sep X 0%

Servos 5%Microcontroller Communication 25-Sep X 10%Hardware Setup 25-Sep X 0%

Wireless System 25%Microcontroller Interface 30-Sep X 50%GUI Interface 30-Sep X 0%

Power System 0%Hardware Setup 30-Sep X X X X 0%

Laser Tx 28%Hardware Setup 11-Sep X X 25%Optics 11-Sep X X 60%Calibration 11-Sep X X 0%

Laser Rx 42%Hardware Setup 25-Sep X X 25%Optics 25-Sep X X 100%Calibration 25-Sep X X 0%

Time to Digital 0%Microcontroller Communication 2-Oct X 0%Calibration 2-Oct X X 0%

David NickRicardo Shane

Responsibility Matrix – Phase 2 & 3PHASE 2 - System Integration 4%GUI 13%

Target GPS Algorithm 9-Oct X 50%Live Video 16-Oct X X 0%Servo Control 23-Oct X X 0%Laser Control 30-Oct X X X 0%

Housing 0%Camera, Laser Tx/Rx Alignment 16-Oct X X X 0%Properly mounted components 23-Oct X X X X 0%Compact Design 30-Oct X X X X 0%

PCB 0%Designed 16-Oct X X X X 0%Manufactured 30-Oct X X X X 0%

PHASE 3 - Testing 0%Testing 0%

Rangefinder 13-Nov X X 0%GPS 6-Nov X X 0%Compass 6-Nov X X 0%Servo Control 6-Nov X X 0%Algorithm 6-Nov X 0%GUI 13-Nov X 0%

David NickRicardo Shane

Progress - PrototypingDate Phase 1 Phase 2 Phase 3

29-Aug 5% 0% 0%5-Sep 10% 0% 0%

12-Sep 16% 0% 0%19-Sep 21% 4% 0%26-Sep 0% 0% 0%3-Oct 100% 0% 0%10-Oct 100% 0% 0%17-Oct 100% 0% 0%24-Oct 100% 0% 0%31-Oct 100% 0% 0%7-Nov 100% 100% 0%14-Nov 100% 100% 0%21-Nov 100% 100% 0%28-Nov 100% 100% 0%5-Dec 100% 100% 100%

Progress – Overall

Environmental conditions Laser transmitter and receiver alignment Divergence t0 Timing Cost

◦ Replacing broken parts

Potential Problems

QUESTIONS?