DIRECTED, HIGH FREQUENCY, OPEN-AIR COMMUNICATION GROUP 29: BRIAN - - PowerPoint PPT Presentation

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DIRECTED, HIGH FREQUENCY, OPEN-AIR COMMUNICATION GROUP 29: BRIAN - - PowerPoint PPT Presentation

Dec 13, 2023 816 likes •1.27k views

DIRECTED, HIGH FREQUENCY, OPEN-AIR COMMUNICATION GROUP 29: BRIAN ASCENCIO (EE) RYAN HEITZ (CPE) SANDY CLINE (PSE) SHANE ZWEIBACH (CPE) 1 PRESENTATION CONTENTS Description, Motivation & Goals Specifications Component Selection

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DIRECTED, HIGH FREQUENCY, OPEN-AIR COMMUNICATION

GROUP 29:

BRIAN ASCENCIO (EE) RYAN HEITZ (CPE) SANDY CLINE (PSE) SHANE ZWEIBACH (CPE)

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SLIDE 2

PRESENTATION CONTENTS

  • Description, Motivation & Goals
  • Specifications
  • Component Selection
  • Design Approach
  • Administrative tasks and budget
  • Design challenges & iterations

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SLIDE 3

PROJECT DESCRIPTION

  • Sending data from a laser transmitter to a receiver.
  • Being able to manually control the direction of the laser.
  • Sending an audio signal to an auxiliary input.
  • Outputting the data through the receivers speaker.

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PROJECT MOTIVATION

  • RF communication is the most popular form of data transfer currently for

untethered devices. Wi-Fi, Bluetooth, and GSM are all broadcast technologies that allow any slave devices within a spherical range to communicate with the host device.

  • This is wasting energy which could be focused on higher-powered and

directed data transfer. This project would contain one primary focus and a secondary focus (given enough available resources):

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SLIDE 5

GOAL #1: CREATE OPTICAL TRANSCEIVER PAIR THAT CAN TRANSMIT DATA IN A SERIALIZED FASHION.

SOLUTION:

GOAL #2: FIND A WAY TO INTEGRATE OBJECT OR BEAM TRACKING TO LET A STATIC TRANSCEIVER TRACK A MOBILE TRANSCEIVER.

ANALOG AUDIO MODULATED LASER SENDS SIGNAL TO PHOTODIODE RECEIVER AND OUTPUTS AMPLIFIED SIGNAL THROUGH A SPEAKER. JOYSTICK AND IR REMOTE INPUT CONTROLS SERVOS

SOLUTION:

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SLIDE 6

SPECIFICATIONS & PROJECT REQUIREMENTS

  • BANDWIDTH ~ 20 kHz
  • SIZE < 1 ft.3
  • WEIGHT < 1 lb.
  • RANGE : [1, 25] ft.

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SLIDE 7

SYSTEM CONCEPT:

  • Transmitter takes audio

signal to modulate laser.

  • User can adjust turret angle.
  • Receiver amplifies signal

from laser and plays through the speaker.

Receiver

Amplifies photogenerated current Drives speaker with amplified signal

Transmitter

User input defines turret angle Laser transmits audio signal

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SLIDE 8

LASER CONSIDERATIONS

Model Output power (mW) Operating current (mA) Operating voltage (V) rise/fall time(ns) Cost (USD) ML925B11F 6 20 1.2 0.2 $16.83 L1550P5DFB 5 30 1.1 0.1 $81.69 154145-VP 5 40 3.0

  • $3.49

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SLIDE 9

JAMECO VALUEPRO 154145-VP

  • Collimation optic simplifies
  • ptical design.
  • Outputs 5 mW of power at 3 V
  • Consumes less than 40 mA of

current.

  • Peak wavelength of 650 nm

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SLIDE 10

OPTICS & DIODE POSITIONING

Transmitting plano-convex optic Receiving bi-convex optic f = 14.9 mm Sets beam divergence f = 25.3 mm Converges beam onto photodiode

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SLIDE 11

PHOTODIODE CONSIDERATIONS

Model NEP (W/Hz1/2) Responsivity (A/W) Rise / fall time (ns) Active area (mm2) Cost (USD) FGA01 4.5*10-15 1.003 (1550 nm) .3 .12 $60.93 FGA015 1.3*10-14 0.95 (1550 nm) .3 .15 $56.65 SFH 203 P .029*10-12 0.75 (650 nm) 5 1 $1.06

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SLIDE 12

OSRAM SFH 203 P PHOTODIODE

  • Responsivity of .75 A/W at 650 nm
  • 1 mm2 active area

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SLIDE 13

DESIGN APPROACH – AUXILIARY INPUT

  • The audio signal is taken from the left
  • r right audio channel to modulate

the laser.

Tip-Ring-Sleeve (TRS) Jack

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DESIGN APPROACH – LASER TX

  • The laser must be

biased to avoid saturation and cutoff to ensure linearity in the signal.

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TRANSMITTER CIRCUIT/SCHEMATICS

  • Voltage regulator sets DC input to op-amp
  • Audio signal is superimposed
  • Laser diode is biased to 3.3 V DC

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TRANSMITTER PCB DESIGN

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RECEIVER CIRCUIT/SCHEMATICS

  • 10 uF capacitor sets gain to 200
  • LM 386 drives an 8 ohm 2” speaker

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RECEIVER PCB DESIGN

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WORKING SOLUTION: MANUAL BEAM TRACKING

  • All servo adjustments are manually controlled by the user
  • No need for accelerometers or sensors
  • Manual controls are all done by the sender MCU
  • No wireless modules needed. No receiver MCU needed
  • Joystick can be used to quickly adjust servos
  • For precise adjustments, a IR remote can be used in two modes
  • “D-Pad” mode: use 4 buttons to control the pan and tilt servos
  • Manual entry: select a servo to control and enter desired angle
  • LCD used to display the angles of the servos, which one is being edited, and the desired angle

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SLIDE 20

MANUAL BEAM TRACKING BLOCK DIAGRAM

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SLIDE 21

MCU: ATMEGA328P-PU

  • Pros:
  • Clock Speed: 20 MHz
  • Through hole mounting
  • Software familiarity (C and Arduino)
  • Resources and troubleshooting
  • Cons:
  • 32 kB Program size

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SLIDE 22

HARDWARE SELECTION

Initial processor selection was SAME70-XPLD based on performance After software requirements were firmed up, Arduino UNO was chosen

Arduino UNO Atmel (Microchip) ATMega328p microcontroller SAME70-XPLD Atmel (Microchip) ATSAME70Q21 microcontroller

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SLIDE 23

OPTICAL & AUDIO COMPONENT SELECTION SUMMARY

  • Laser – Jameco Valuepro 154145-VP
  • Photodiode – Osram SFH 203 P
  • Voltage regulator – LM7805CT
  • Op-amps – LM 386, LM 358N

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SLIDE 24

SERVO CONTROL COMPONENT SELECTION SUMMARY

  • MCU: ATMEGA 328P-U
  • LCD: 16x2 LCD
  • VOLTAGE REGULATOR: 7805 (5V)
  • All hardware requires 4.8V-6V
  • Familiarity from labs
  • Standard IR Reciever
  • Standard Joystick
  • Servos: Micro size
  • Just holding a laser emitter (no heavy

lifting required)

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SERVO CONTROL PROTOTYPES

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SERVO CONTROL PROTOTYPES

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SERVO CONTROL PROTOTYPES

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SERVO MICROCONTROLLER SCHEMATIC

LCD MCU IR

Voltage Regulator

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SLIDE 29

SERVO MICROCONTROLLER PCB DESIGN

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SLIDE 30

SOFTWARE BLOCK DIAGRAM

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SLIDE 31

DEVICE POWER

  • Receiver amp

Transmitting circuit pulls .03 A from the source at 9 V .378 W consumed .18 W consumed

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SLIDE 32

OP AMPS

  • LM358
  • Advantage
  • Low power
  • Multi-usage
  • Dual Op Amps
  • Usage
  • Amplified signal
  • High pass filters
  • Low pass filter
  • Analog addresses
  • LM386
  • Advantage
  • Low power
  • Audio transmitting

devices

  • usege
  • Battery power devices
  • Guitar amplifier

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SLIDE 33

TRANSMITTER HOUSING

  • Holes for LCD, audio cable and

turret.

  • Locations set for microcontroller and

transmitter circuit.

  • Compartment for 9 V batteries
  • Slots for cable routing.

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SLIDE 34

RECEIVER HOUSING

  • Contains 9 V battery and soldered

perfboard mounted on standoff.

  • Cutouts for onboard speaker and

receiving optic.

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TURRET PLATFORM, JOYSTICK GRIP , DIODE MOUNTS

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ADMINISTRATIVE TASK LAYOUT

Team Members PCB Schematics Embedded Systems Software Design Components Selection Optics Housing Brian Primary Secondary Secondary Ryan Primary Primary Secondary Sandy Secondary Primary Primary Primary Shane Primary Primary Secondary

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PROJECT EXPENSES

Part Quantity Cost ($ USD) Microcontroller 1 $5.95 Laser 1 $.60 Amplifier 1 $.33 Pan and Tilt Servos 1 $19.42 Photodiode 1 $1.13 LCD 1 $5.99 PCB 3 $31.88

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SLIDE 38

PROJECT DIFFICULTIES & CHALLENGES

  • A change in understanding and part availability changes the implementation
  • f design.
  • The core function of data transmission and electrical work must precede the

work of opto-mechanical design and beam alignment automation.

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ORIGINAL GOAL: DIGITAL TRANSMISSION

  • Behind schedule on necessary components
  • Required more involved signal processing analysis
  • Pushed optics & housing work too far behind

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ATTEMPTED SOLUTION: ACCELERATION BASED TRACKING

Problems?

  • Double integration for acceleration isn’t accurate. The error also compounds.
  • Objects moving at different constant speeds have the same acceleration but different final positions
  • What’s the difference between accelerating one way and decelerating while moving the other?
  • Now limited by the error rates of the wireless modules.

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SLIDE 41

ORIGINAL MCU: ATSAME70J19A

  • Pros:
  • Clock Speed: 300 MHz
  • Connectivity: Ethernet, USB, UART, SPI, I2C
  • Program Memory Size: 512 KB
  • Cons:
  • Difficult to program
  • Only SMD (difficult to solder and work with)

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EARLY PROTOTYPE – DIGITAL AUDIO TX/RX

  • 8KHz 8-bit WAV file
  • Read by microcontroller from SD card
  • Transmitted as serial bits via laser ( 76680 baud rate)
  • Received by laser receiver
  • Output to amplifier and 8 Ohm speaker

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SLIDE 43

QUESTIONS?

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