Infection

There is a disease outbreak! Will you find patient zero?!?

Infection is a distributed game which simulates the spread of an illness. The goal is to stop the outbreak before every player dies!

Number of players: 1 Master and 4, or more, additional players. The Master and all other players need a micro:bit with battery pack.

In this game, a Master micro:bit infects a single, initial player (“patient zero”) with the illness. The infected player is contagious immediately but won’t show any signs sickness during the incubation time. The sickness gets transmitted when two micro:bits get close enough to each other to “contract the disease”. After the incubation period, a sad face appears on the screen. After the sickness period, the player will eventually die and a skull displays on the screen. Dead players are out of the game.

If at least one player survives the outbreak, the game is won. Otherwise, try again!

Infection is an engaging game that will get your students running around. We recommend playing it outside, or in a large open area, to give more space for the activity.

How to play

Press A+B to enter Master mode (there’s only one Master in a game).

Wait for players to be paired. The number of paired players will display on the screen. When paired, a letter appears on the player’s screen, this letter is the player’s identity.

Once all of your players are registered, press A+B to start the infection game. The game randomly picks a player as patient zero.

A player will transmit the disease to another player if close enough (detecting a sufficient RSSI), and if a certain probability (TRANSMISSIONPROB) of disease transfer is reached. During the incubation phase (INCUBATION), the player does not show any sign of illness (happy face). After that phase, the player gets sick and shows a sad face on the screen. After the sick (sad) face, the player dies and a skull shows up.

Once the game is over, the micro:bit will show the player’s id (A, B, C…), health, and the id of the player who infected them. The Master micro:bit will show the identity of patient zero.

Icons used in the game:

Pairing: IconNames.Ghost
Paired: IconNames.Happy
Dead: IconNames.Skull
Sick: IconNames.Sad
Incubating: IconNames.Confused
Healthy: IconNames.Happy

Take a look at this video to see how the micro:bit uses radio to spread “disease” in this game:

This code uses language features, such as switch or enum, that are not supported in blocks. As a result, it will not convert back to blocks.

JavaScript code

Run
/**
 * Infection game
 *
 * Flash all micro:bits with this script
 *
 * Press A+B to enter master mode (1 per game)
 *
 * Wait for players to be paired. The number of paired player will display on screen.
 * An icon will appear on player's screen.
 *
 * Press A+B to start the infection game. The master will pick a random
 * player as patient zero.
 *
 * A player will transmit the disease if close enough (RSSI)
 * and with a certain probability (TRANSMISSIONPROB).
 * During the incudation phase (INCUBATION), the player does not show any sign
 * of illness. After that phase, the sad face shows up.
 *
 * The game will automatically stop once all players are dead or healthy. The master can
 * also press A+B again to stop the game.
 *
 * Once the game is over, the micro:bit will show the player id (A,B,C...), health and
 * who infected him.
 *
 * Icons used in the game:
 *
 * Pairing: IconNames.Ghost
 * Paired: IconNames.Happy
 * Dead: IconNames.Skull
 * Sick: IconNames.Sad
 * Incubating: IconNames.Confused
 * Healthy: IconNames.Happy
 *
 */
const INCUBATION = 20000; // time before showing symptoms
const DEATH = 40000; // time before dying off the disease
const RSSI = -45; // db
const TRANSMISSIONPROB = 40; // % probability to transfer disease

enum GameState {
    Stopped,
    Pairing,
    Infecting,
    Running,
    Over
}

enum HealthState {
    Healthy,
    Incubating,
    Sick,
    Dead
}

enum MessageKind {
    PairRequest,
    PairConfirmation,
    HealthSet,
    HealthValue,
    InitialInfect,
    TransmitVirus,
    GameState
}

const GameIcons = {
    Pairing: IconNames.Ghost,
    Paired: IconNames.Happy,
    Dead: IconNames.Skull,
    Sick: IconNames.Sad,
    Incubating: IconNames.Confused,
    Healthy: IconNames.Happy
}

class Message {

    private _data: Buffer;

    constructor(input?: Buffer) {
        this._data = input || control.createBuffer(13);
    }

    get kind(): number {
        return this._data.getNumber(NumberFormat.Int8LE, 0);
    }

    set kind(x: number) {
        this._data.setNumber(NumberFormat.Int8LE, 0, x);
    }

    get fromSerialNumber(): number {
        return this._data.getNumber(NumberFormat.Int32LE, 1);
    }

    set fromSerialNumber(x: number) {
        this._data.setNumber(NumberFormat.Int32LE, 1, x);
    }

    get value(): number {
        return this._data.getNumber(NumberFormat.Int32LE, 5);
    }

    set value(x: number) {
        this._data.setNumber(NumberFormat.Int32LE, 5, x);
    }

    get toSerialNumber(): number {
        return this._data.getNumber(NumberFormat.Int32LE, 9);
    }

    set toSerialNumber(x: number) {
        this._data.setNumber(NumberFormat.Int32LE, 9, x);
    }

    send() {
        radio.sendBuffer(this._data);
        basic.pause(250);
    }
}

const playerIcons = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
class Player {
    id: number;
    icon: number;
    health: HealthState;
    show() {
        basic.showString(playerIcons[this.icon]);
    }
}

// common state
let state = GameState.Stopped;

// master state
let master = false;
let patientZero: Player;
const players: Player[] = [];

// player state
let paired = false;
let infectedBy = -1; // who infected (playerIcon)
let infectedTime = 0; // local time when infection happened
let playerIcon = -1; // player icon and identity
let health = HealthState.Healthy;

// get a player instance (creates one as needed)
function player(id: number): Player {
    for (const p of players)
        if (p.id == id) return p;

    // add player to game
    let p = new Player();
    p.id = id;
    p.icon = (players.length + 1) % playerIcons.length;
    p.health = HealthState.Healthy;
    players.push(p);
    serial.writeLine(`player ==> ${p.id}`)

    return p;
}

function allDead(): boolean {
    for (const p of players)
        if (p.health != HealthState.Dead) return false;
    return true;
}

function gameOver() {
    state = GameState.Over;
    if (patientZero)
        patientZero.show();
}

function gameFace() {
    switch (state) {
        case GameState.Stopped:
            basic.showIcon(GameIcons.Pairing);
            break;
        case GameState.Pairing:
            if (playerIcon > -1)
                basic.showString(playerIcons[playerIcon]);
            else
                basic.showIcon(paired ? GameIcons.Paired : GameIcons.Pairing, 1);
            break;
        case GameState.Infecting:
        case GameState.Running:
            switch (health) {
                case HealthState.Dead:
                    basic.showIcon(GameIcons.Dead, 1);
                    break;
                case HealthState.Sick:
                    basic.showIcon(GameIcons.Sick, 1);
                    break;
                default:
                    basic.showIcon(GameIcons.Healthy, 1);
                    break;
            }
            break;
        case GameState.Over:
            // show id
            basic.showString(playerIcons[playerIcon]);
            basic.pause(2000);
            // show health
            switch (health) {
                case HealthState.Dead:
                    basic.showIcon(GameIcons.Dead, 2000);
                    break;
                case HealthState.Sick:
                    basic.showIcon(GameIcons.Sick, 2000);
                    break;
                case HealthState.Incubating:
                    basic.showIcon(GameIcons.Incubating, 2000);
                    break;
                default:
                    basic.showIcon(GameIcons.Healthy, 2000);
                    break;
            }
            // show how infected
            if (infectedBy > -1) {
                basic.showString(" INFECTED BY");
                basic.showString(playerIcons[infectedBy]);
                basic.pause(2000);
            } else {
                basic.showString(" PATIENT ZERO");
                basic.pause(2000);
            }
            // show score
            game.showScore();
            basic.pause(1000);
            break;
    }
}

// master button controller
input.onButtonPressed(Button.AB, () => {
    // register as master
    if (state == GameState.Stopped && !master) {
        master = true;
        paired = true;
        state = GameState.Pairing;
        serial.writeLine("registered as master");
        radio.setTransmitPower(7); // beef up master signal
        basic.showString("0");
        return;
    }

    if (!master) return; // master only beyond this

    // launch game
    if (state == GameState.Pairing) {
        // pick 1 player and infect him
        patientZero = players[randint(0, players.length - 1)];
        // infecting message needs to be confirmed by
        // the player
        state = GameState.Infecting;
        serial.writeLine(`game started ${players.length} players`);
    } // end game
    else if (state == GameState.Running) {
        gameOver();
    }
})

radio.setGroup(42);
radio.onReceivedBuffer(function (receivedBuffer: Buffer) {
    const incomingMessage = new Message(receivedBuffer);
    const signal = radio.receivedPacket(RadioPacketProperty.SignalStrength);
    if (master) {
        switch (incomingMessage.kind) {
            case MessageKind.PairRequest:
                // register player
                let n = players.length;
                player(incomingMessage.fromSerialNumber);
                // show player number if changed
                if (n != players.length) {
                    basic.showNumber(players.length);
                }
                break;
            case MessageKind.HealthValue:
                let p = player(incomingMessage.fromSerialNumber);
                p.health = incomingMessage.value;
                // check if all infected
                if (allDead())
                    gameOver();
                break;
        }
    } else {
        switch (incomingMessage.kind) {
            case MessageKind.GameState:
                // update game state
                state = incomingMessage.value as GameState;
                break;
            case MessageKind.InitialInfect:
                if (infectedBy < 0 &&
                    incomingMessage.toSerialNumber == control.deviceSerialNumber()) {
                    // infected by master
                    infectedBy = 0; // infected my master
                    infectedTime = input.runningTime();
                    health = HealthState.Incubating;
                    serial.writeLine(`infected ${control.deviceSerialNumber()}`);
                }
                break;
            case MessageKind.HealthSet:
                if (incomingMessage.toSerialNumber == control.deviceSerialNumber()) {
                    const newHealth = incomingMessage.value;
                    if (health < newHealth) {
                        health = newHealth;
                    }
                }
                break;
            case MessageKind.PairConfirmation:
                if (!paired && state == GameState.Pairing &&
                    incomingMessage.toSerialNumber == control.deviceSerialNumber()) {
                    // paired!
                    serial.writeLine(`player paired ==> ${control.deviceSerialNumber()}`)
                    playerIcon = incomingMessage.value;
                    paired = true;
                }
                break;
            case MessageKind.TransmitVirus:
                if (state == GameState.Running) {
                    if (health == HealthState.Healthy) {
                        serial.writeLine(`signal: ${signal}`);
                        if (signal > RSSI &&
                            randint(0, 100) > TRANSMISSIONPROB) {
                            infectedBy = incomingMessage.value;
                            infectedTime = input.runningTime();
                            health = HealthState.Incubating;
                        }
                    }
                }
                break;
            case MessageKind.HealthValue:
                if (health != HealthState.Dead && signal > RSSI) {
                    game.addScore(1);
                }
                break;
        }
    }
})

// main game loop
basic.forever(() => {
    let message: Message;
    if (master) {
        switch (state) {
            case GameState.Pairing:
                // tell each player they are registered
                for (const p of players) {
                    message = new Message();
                    message.kind = MessageKind.PairConfirmation;
                    message.value = p.icon;
                    message.toSerialNumber = p.id;
                    message.send();
                }
                serial.writeLine(`pairing ${players.length} players`);
                basic.pause(500);
                break;
            case GameState.Infecting:
                if (patientZero.health == HealthState.Healthy) {
                    message = new Message();
                    message.kind = MessageKind.InitialInfect;
                    message.toSerialNumber = patientZero.id;
                    message.send();
                    basic.pause(100);
                } else {
                    serial.writeLine(`patient ${patientZero.id} infected`);
                    // show startup
                    basic.showIcon(GameIcons.Dead);
                    state = GameState.Running;
                }
                break;
            case GameState.Running:
                for (const p of players) {
                    message = new Message();
                    message.kind = MessageKind.HealthSet;
                    message.value = p.health;
                    message.toSerialNumber = p.id;
                    message.send();
                }
                break;
            case GameState.Over:
                if (patientZero)
                    patientZero.show();
                break;
        }
        message = new Message()
        message.kind = MessageKind.GameState;
        message.value = state;
        message.send();
    } else { // player loop
        switch (state) {
            case GameState.Pairing:
                // broadcast player id
                if (playerIcon < 0) {
                    message = new Message();
                    message.kind = MessageKind.PairRequest;
                    message.fromSerialNumber = control.deviceSerialNumber();
                    message.send();
                } else if (infectedBy > -1) {
                    message = new Message();
                    message.kind = MessageKind.HealthValue;
                    message.fromSerialNumber = control.deviceSerialNumber();
                    message.value = health;
                    message.send();
                }
                break;
            case GameState.Infecting:
                message = new Message();
                message.kind = MessageKind.HealthValue;
                message.fromSerialNumber = control.deviceSerialNumber();
                message.value = health;
                message.send();
                break;
            case GameState.Running:
                // update health status
                if (health != HealthState.Healthy && input.runningTime() - infectedTime > DEATH)
                    health = HealthState.Dead;
                else if (health != HealthState.Healthy && input.runningTime() - infectedTime > INCUBATION)
                    health = HealthState.Sick;
                // transmit disease
                if (health == HealthState.Incubating || health == HealthState.Sick) {
                    message = new Message();
                    message.kind = MessageKind.TransmitVirus;
                    message.fromSerialNumber = control.deviceSerialNumber();
                    message.value = playerIcon;
                    message.send();
                }
                message = new Message();
                message.kind = MessageKind.HealthValue;
                message.fromSerialNumber = control.deviceSerialNumber();
                message.value = health;
                message.send();
                break;
        }
        // show current animation
        gameFace();
    }
})

basic.showIcon(GameIcons.Pairing)

Infection

How to play

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JavaScript code