TARGET: Touch-Activated Response Gaming Entertainment Table

ECE SDP11

Team Siqueira:Pat DeRoy,

Cory Gorman,Marc Perras

TARGET:Touch-Activated Response Gaming

Entertainment Table

Preliminary Design Review

2ECE SDP11

“All-in-One” Games Table Many different pieces

• Often heavy• Inconvenient

Difficult to switch between games

Can cost as much as $1000

Solution: Engineering!• Make a digital games

table• “Just push a button”

3ECE SDP11

What does such a system need to do? Must stay within $500 budget Must be able to handle inputs from multiple users

simultaneously Must be able to accurately simulate a real game

with correct physics and timing

4ECE SDP11

Multi-Touch Surface Large screen

connected to a computer

Responds to user touch as input

Can handle many users at once

Suits our needs very well!

Microsoft Surface: $12,500

5ECE SDP11

Building a Multi-Touch System Input: User Touch. Picked up by IR camera, sends

image of “finger blobs” to main system. System processes blobs to find touch locations

and interprets as tapping, dragging, etc. Output: After reacting to the input, the system

outputs the screen image to a projector.• The projector displays the image on the surface of the

table from below.

6ECE SDP11

Frustrated Total Internal Reflection• Shine infrared LEDs into acrylic

plastic along the perimeter. • Arrange LEDs so that they

engage in total internal reflection within the acrylic.

• When finger is placed on the acrylic, the total internal reflection is disrupted, due to the fact that a finger has a higher refractive index than air

• Infrared light escapes, and an infrared camera placed below the acrylic surface will see this escaped light

7ECE SDP11

Block Diagram

8ECE SDP11

Image Processing From camera image,

find finger blobs Get the X, Y locations

of the blobs Compare to previous

locations to determine which have been moved, which are new touches, etc.

Determine how to react to this input

9ECE SDP11

Constraint: Speed and Timing Some estimates:

• Camera resolution: 320x240 = 76800 pixels• Projector resolution: 640x480 = 307200 pixels• Ideally, would run at more than 30 frames/second.• Tasks for each frame:

• Find finger locations (76800)• Interpret locations (76800)• Update game state (307200)• Output image (307200)

• Σ = 768,000 pixels• 4 bytes per pixel (RGBA)• => 3,072,000 bytes per frame

10ECE SDP11

Constraint: Speed and Timing Suppose it takes 5 cycles of processing per byte. 5 cycle/byte * 3072000 byte/frame = 1.536*107

cycles/frame * 30 frame/second = 4.608*108 cycles/sec. Roughly equals 460 MHz.

11ECE SDP11

Other Constraints Size: The size of the surface is limited by the

throw distance of the projector and the thickness of the acrylic.• Too-thin acrylic will bend in the middle

Brightness: The table must be able to be viewed easily in regular office lighting.• 1000 lumens projector?

Budget

12ECE SDP11

Estimated Budget System: provided by Intel through Prof. Wolf PS3 Camera: $40 Mirror(s): $10-$20 IR LEDs: ~150 @ $0.20 = $30 Casters: 4 @ $5 = $20 Vellum: free Fans:free Wood: free Acrylic: free Projector: free Tentative Total: $110

13ECE SDP11

Design Alternatives Board vs. PC

• Choice of Board Other forms of multi-touch that are not FTIR-

based• Diffused Illumination• Laser Light Plane (LLP)

Projector• Buy one or build our own?• Mirrors vs. lens system to achieve short throw distance

Size of the table

14ECE SDP11

Design Concept

15ECE SDP11

Deliverables Implement FTIR Projector position Image and graphics processing Physics engine Multiple games User menu User manual Attract mode

16ECE SDP11

Timeline 1. Have working FTIR effect. (End of October)

• Frame for acrylic panel with infrared LEDs. When touched, blob visible on camera.

2. For MDR: Determine position of projector and mirrors. (End of November)• Build a temporary table with variable height to try

different orientations. 3. Get basic system working using a PC. (End of

semester)

17ECE SDP11

Timeline 4. Successfully interface board with camera and

projector. (End of February)• Image Processing completed.• “Draw” circles around touches.

Software: (End of March)• 5. Create control menus.• 6. Create physics engine.• 7. Create game applications.• 8. Create game selection menus.

9. Finish table, including cooling system. (End of March)

10. Possible Expansion and Finishing Touches

18ECE SDP11

Timeline

PDR MDR CDR FPR SDP Day

1. FTIR

2. Projector

3. PC prototype

4. Interface Components

5-8. Software

9. Finished Table

10. Finishing Touches/ Expansion

19ECE SDP11

Team Roles FTIR Panel:

• Solder LEDs: “Assembly line”• Build frame: Pat• Polish acrylic: Marc• Wire LEDs: Cory• Prepare vellum with silicon: Cory

Projector setup:• Experiment with projector/throw distances: Marc• Placement/modification of mirrors: Marc• Layout of components: Pat• Build temporary casing for prototype: Pat

Website: Cory

20ECE SDP11

Conclusion Our project is good for SDP:

• Expandable: with more time, can add more games and features

• Good amount of both hardware and software• “Demo-able”: easy to show off and explain at SDP Day

Our project is a good product:• Markets: Home/Personal use, or sell to bars/arcades

with addition of coin-op unit• Could expand to other applications besides just games• Relatively inexpensive

21ECE SDP11

Questions?