TEAM LLAMP

Nadja MemicSteve Karcher

Sri Teja BasavaFrancis Yi

Laser Lattice Associative Multi-touch Product

Preliminary Design Review

04/18/23 Department of Electrical & Computer Engineering 1

PDR Outline• Project Objectives• Outline of Approach

• Frame• Input Processing Box• Driver

• Implementation of Subsystems• Division of Labor• Timeline• Build or Buy?• Costs • Risks• Questions?

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04/18/23 Department of Electrical & Computer Engineering 3

Project Objectives

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Project Objectives• 40” User Input Area• Multi-touch Support• Simple Drawing Tool

Extensions• Multi-user Software Application

• e.g. Classroom Finder, Public Information Kiosk

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Outline of Approach

Frame Input Processing Box

DriverSoftware Application

(Drawing Tool)

USB 2.0

Touch Input

N

Interrupted X and Y Positions

Pointer Coordinates

Screen Output

FPGA

Computer

Rx Status

N Number of sensors

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FrameFunctionality

Gets multi-touch input from user

InputsUser input

OutputsSignals indicating Rx status

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Frame

40” Input Area

Tx

Tx…T

x

Tx …

Rx

Rx…

Rx

Rx …

Analog

Analog

+

-

VT

+

-

VT

Analog

Analog

+

-

VT

+

-

VT

Nx Number of horizontal Rx/TxNy Number of vertical Rx/TxVT Threshold Voltage

Nx

Nx

NyNy

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Input Processing Box• Functionality

• Processes and converts the interrupts for use by the driver

• Inputs• Signals indicating Rx status

• Outputs• Data indicating interrupted x and y positions

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Input Processing Box

Change Logic

Parallel to Serial Conversion Logic

Memory Buffer

Clock

Clock

USB Interface

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Driver• Functionality

• Gets the contents of memory buffer and interprets the x and y position data. This can then be used by the computer to control a mouse pointer.

• Inputs• Data indicating interrupted x and y positions from

memory buffer

• Outputs• Mouse control signal

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Driver

Proximity Detection Module

Average Calculation Module

USB Driver

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Implementation of Subsystems

Pictures from left to right from: http://www.knjn.com/ShopItemsPics/Board_Xylo-L.jpg, http://en.wikipedia.org/wiki/Image:Windowsloadingdrivers.jpg, http://www.publicdataweb.com/PDW/images/gif/Kiosk-BusStop-Anime.gif

12

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Division of Labor and Responsibilities

1. Frame:

- Housing

- Circuitry/Board

- Tx/Rx Research

2. Input Processing Box:

- FPGA choice

- Logic algorithm development

- Adapting to our platform

3. Driver Development:

- Updating, averaging, proximity & toggling

4. Software Application:

- Implementation of painting ftn

Francis & Nadja

Steve & Teja

Entire Team

Steve & Teja

Francis, Nadja & Teja

Francis, Steve & Nadja

Teja & Francis

Entire Team

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Timeline• User Input Area

Test and choose solutionGrid constructionChoose logic solutionInput processing boxDevelop on DEV board

• Write driver code

• Application

• System Wide Integration

Board Layout

Develop support circuitry

•Transplant DEV board

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Timeline

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Timeline

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Build or Buy Decisions

Build

FrameLogic Circuit / Board LayoutDriver SoftwareSoftware (Paint, Kiosk)Interconnections between sensors and FPGA

Buy

Power SuppliesProjectorComputerUSB ModuleFPGA ChipLaser DiodesPhotodiodes

Pictures from: http://www.eio.com/repairfaq/sam/ldclose.gif, http://img.engadget.com/common/images/3363705371535783.JPG?0.299055096787738, http://www.futurlec.com.au/images/USBMOD1.jpg, http://static.howstuffworks.com/gif/power-supply5.jpg,http://www.itreviews.co.uk/graphics/normal/hardware/h930.jpg

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Item $/unit # of units Total

Laser diode 2.50 100 $250.00

Photodiode 2.50 100 $250.00

Frame material 100.00 1 $100.00

Circuit board 66.00 4 $264.00

Power supply 60.00 1 $60.00

FPGA chip 80.00 1 $80.00

Miscellaneous $55.99

Grand Total: $999.99

Costs

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Risks and Contingency PlanRisks:

-Dead spots-Differentiating between inputs-Laser alignment within frame-Cost of laser diodes-Health risk-Time to complete-Lack of Experience

Plan B:

-Capacitive touch-screen design-Different algorithms or single touch-Manually aligning the lasers-Smaller user area-Resort to LED rather than lasers-Implement a weaker light source-Cut back on software applications

Source: http://www.eyemdlink.com/images/illustrations/small/yagLaser.jpg

Thank You!

Questions?

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?