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Project “ RedEye ”

Project “ RedEye ”. University of Central Florida College of Electrical Engineering and Computer Science Senior Design Fall 2011. Group 8 David Morrow Ricardo Rodriguez Shane Theobald Nick Bauer. Motivation. Wanted to gain experience in many different engineering disciplines C# - GUI

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Project “ RedEye ”

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  1. Project “RedEye” University of Central Florida College of Electrical Engineering and Computer Science Senior Design Fall 2011 Group 8 David Morrow Ricardo Rodriguez Shane Theobald Nick Bauer

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

  3. 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

  4. Project Specifications • 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

  5. Block Diagram

  6. Operational Flow Chart

  7. Rangefinder Subsystem • 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

  8. Time-of-Flight Rangefinder

  9. Receiver Module Components • Photodetector • HV Power Supply • Front End Amplifier (Transimpedance Amp) • NIR optical filter • Receiver Lens

  10. Avalanche Photodiode (Detector) • 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

  11. APD Design Characteristics • Peak Spectral Response • Cost and Availability • Minimum Dark Current • Required Bias Voltage

  12. 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

  13. 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

  14. Transimpedance AmplifierTI OPA656 • Converts photocurrent into voltage • High Slew Rate at 290V/µs • Low Input Noise Voltage 7nV/√HZ • FREE—Sampled

  15. Receiver System Schematic

  16. Optical Bandpass Filter • Filter Specs • 2 in X 2in X .1in • CWL 905.9nm • BBW 54.0nm • Peak transmission 79%

  17. Receiver Prototype Overview Lens Tube Assembly Receiver Electronics

  18. Power Received Ptx e(-αRtx) ρ e(- αRrx) Arx Topt Prec = πRrx2

  19. Threshold Detection • Prevent False Alarms • Capture as much energy as possible • Keep noise floor low • Set threshold

  20. Laser Transmitter Design Parameters • 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

  21. Laser Diode Options HA!

  22. 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 5mm 5.9mm

  23. Diode Driver CCAIXYS PCO 7110-50-15 • 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

  24. Diode Driver continued • 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)

  25. Diode Driver Continued • JP1 Connection

  26. Laser Transmitter Diagram

  27. Transmitter Prototype Overview Transmitter Electronics

  28. Voltage Requirements • 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

  29. Power Supply Overview

  30. 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

  31. Software Design • 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

  32. Embedded Overview Compass GPS MCU XBee TDC Pan & Tilt

  33. MCU: ATmega328 Clock Speed Core Size I/O Pins Package Size Memory UART/I2C/SPI/PMW Operating Voltage Price 16 MHz 8 bit 14 DIP 28 32 kB 2 / 1 / 2 / 6 1.8 – 5.5V $6.27 • Mounted on Arduino development board • Arduino Uno development environment compatibility

  34. IDE: Arduino Uno • C Programming language • Allows for flexible troubleshooting • Large support community • SPI, I2C, & Serial libraries

  35. GPS: EM-406A SiRF III  4.5 – 6.5V 44 mA 4800 1.023 MHz UART; RS-232 5m WAAS $59.95 Input Voltage Input Current Baud Rate C/A code Comm. Protocol Accuracy Price 5cm 5cm

  36. Compass: HMC6352 2.7 – 3V 2 – 10mA 0.1 gauss 0.5 degrees I2C 0.14 grams $34.95 Input Voltage Input Current Field Range Resolution Comm. Protocol Weight Price • Two axis digital compass • Provides heading in degrees from magnetic north

  37. Wireless Comm: Overview • 100ft radial distance • Omni-directional link • Low Power Consumption

  38. Wireless Comm: XBee Series 2 2.8 – 3.6V 40 mA 2 mW (+3 dBm) -98 dBm 250 Kbps 1200 – 1 Mbps 2.4 GHz 133ft 400ft Zigbee (802.15.4) Whip (dipole) $25.95 (X2) Input Voltage RX/TX Current Transmit Power TX Sensitivity RF Data Rate Baud Rate Frequency Band Indoor Range Outdoor Range Protocol Antenna Price 3cm 3cm

  39. Servos: Hitec HS-485HB 4.8 – 6V .18 sec/600 83.3 oz/in 450 8.8 mA / 180 mA 3 Pole Ferrite 1.59 oz $16.99 Operating Voltage Operating Speed (6V) Stall Torque Operating Angle Current Drain (6V) Motor Type Weight Price

  40. Pan & Tilt: Hitec SPT200 5.5 oz 135o 2 lbs $45.99 Weight (w/o servos) Tilt Swing Max. Payload Price

  41. Schematic Overview

  42. Camera and Tx/Rx • 1/3” Sony CCD microboard camera • NTSC format • 510x492 pixels • 900MHz Tx/Rx combo

  43. GUI Functional Flow Diagram Connect to XBee and Video Open GUI User Input no yes Fire Laser Move Camera Poll GPS Poll Compass Display Info

  44. GUI - UML Diagram PositionalData RangeFinder Target • double CompassHeading • - double latitude • - string LatitudeHeading • - double longitude • - string LongitudeHeading + PositionalData Info + int distance + PositionalData targetData + RangeFinder rangefinderData • - PollGPS() • PollCompass() • - PollLaser() • - DisplayData() • CalculateGPS() • DisplayData()

  45. GUI – Prototype Layout

  46. Target GPS Algorithm • 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)

  47. Target GPS Algorithm – cont. • 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)

  48. Budget

  49. Responsibility Matrix – Phase 1

  50. Responsibility Matrix – Phase 2 & 3

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