Team 6: RADAGAST

Team Members

Chanin LaohaphanMian Luo

Andrew NohBrian Pfiffner

Jon Wu

claohaph

lmian

anoh

bpfiffne

jwu2

Concept

• Allow children to enjoy painting in real time on a collaborative digital canvas with smart phones

• Existing systems are usually web based and the modes of input required are unsuitable for children. Our system is simpler and more intuitive for children

Requirements

Functional requirements: • Accepts user inputs and converts data to positions and

effects on the canvas• The system will have a defined network protocol to allow

for interoperability between multiple clients and server devices

Reliability requirements: The system will degrade gracefully from connection lossSecurity requirements: The server will support a connection limiting systems for

users

Architecture

Components• X86 computer• Projector• Smart phones

User interface of our system:

Experimentation Campaign

• Metrics: Latency, throughput (from server and client)

• Measurements: Profiling (gprof, traceview), client -> server simulations

Results: Android profiling

Results: Client simulation

Insights from Measurements

• Latency increases linearly as the number of clients increases

• Client display is the bottleneck because on Android, you have to redraw the whole screen every time you want to add something to the drawing

Performance

Strategies to improve the performance• Update the touch screen less often• Reduce the bitmap buffer size on the touch

screen so redrawing takes shorter time• Limit debugging tools to reduce the bus

pressure

Conclusions

What we accomplished:• Basic multi-client implementation• Limiting number of users, waiting queueOpen issues:• Wands• Other smart phones (iPhones)• Additional modes (offline mode)

Conclusions

What we would do differently:• Make our goal clear by communicating with

sponsors so we don’t spend time developing features they don’t desire (using smart phones to calibrate and draw by reading accelerometer data)

Conclusions

What we learned:• Android programming• Developing over multiple platforms• Good planning saves lots of implementation time• Commenting code is invaluable• Reading and interpreting data from phone compass

and Wiimotes• Choosing hardware we are familiar with or with good

documentation

Demo Video

• Demo Video

Thank you !