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BLOKUS

Team A1: Blokus

Nadine Bao, Jonathan Nee, Aria Zhang

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Application Area and Solution Approach

Implement socially-distanced game of Blokus
Support up to 4 players per game
Create game sessions
Game play mechanics:

Place pieces down on your own board
Piece tracked using camera and CV
Relayed to opponents through web server
See opponents’ physical board light up based on your move via LEDs

Only allow valid moves
Ability to resume game at a later time

Our group is targeting the problem of being able to play board games physically in person during Covid times. Given that board games often do not translate well to playing virtually, because much of the appeal comes from the physical aspect of being able to physically touch pieces and move pieces on the board, we want to be able to implement a socially-distanced game of Blokus. Based on the usual game of Blokus, our implementation has to be able to support 4 players. Pieces are placed on your own board, tracked using a camera and CV, through a web server to the other players’ boards. There, the local software will get the respective piece LEDs to light up the corresponding squares on the grid. We will also ensure that only valid moves are allowed, and implement the ability to resume the game at a later time.

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System Overview

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Complete Solution

Public Demo

Multiplayer gameplay

Live camera feed of game

LED board state
OpenGL game

4-player game play, 3 controlled �using computer

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Complete Solution

Introduce hardware and software setup
Video Demo

Gameplay

Simulate 2-players playing the game using physical boards
4-player game play

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Metrics - High Level User Requirements

Name	Req.	Measurement	Description
End to end latency	150ms	CV: 82ms (60-120ms) Server: 28ms (23-37ms) Arduino: 23ms (10-40ms) Total: ~133ms	End to end latency from piece placed to LED being lit Avg time of individual components Additional delay due to sending cell by cell, could send all at once
Accuracy	100%	20/20 tests passed	Accuracy of piece placed on one board to LED lighting up on opponent board, including invalid moves Measured from one board to lighting up on board with LEDs

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Metrics - Computer Vision

Name	Requirement	Measurement	Description
Color + Coordinate Identification Video Test	100% pass	20/20 tests	Given reasonable lighting conditions, identification of correct pieces in correct cells by CV Placed a piece down, and measured if correct coordinates were output in software
Validity of Moves	100% pass	20/20 tests	Given piece placed, local client to determine validity Placed a piece down, and measured if software correctly responded to valid/invalid move

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Metrics - Client Software + Server

Name	Requirement	Measurement	Description
Client 1 to Server to Client 2	< 40 ms	Average: 28.3 ms Max: 37.4 ms Min: 23.5 ms	Sending messages from client to server to client (200 trials)
Valid move verification	< 1 ms	Average: 0.047 ms Max: 0.073 ms Min: 0.035 ms	Timing when GUI received mouse input to displaying on screen (100 trials)

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Metrics - Arduino + LEDs

Name	Requirement	Measurement	Description
Arduino Code Execution Time	<1ms	~.78 ms 10 timed code execution	Time necessary to: Parse row, col, color Calculate LED index Determine RGB values
Accurate LEDs Behavior	100% pass	20/20 visual tests passed	Expected color and coordinates of each piece Given a color and coordinate, to light up that respective LED that color

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Trade-offs

CV image resizing

Immediate time sink vs. long term sink when looping through image

Website vs. OpenGL

Accessibility
Latency

LED board construction

Budget vs. Time: hand-drilling holes per square
Outsourcing construction (ex. PCB, 3D-printing)

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Project Management

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Lessons Learned

Unexpected issues can arise during integration

Start testing on different platforms early (Windows)

Have backup components (LEDs and RPis)
Sacrifice some latency for easier to use libraries and more compatible technologies
It is great to plan for contingencies, but diving in and actually testing things out is also very important