Hot or Cold Seeker

Introduction

In this tutorial, you will create the code for the seeker in the Hot-Or-Cold game. The seekers micro:bit look for micro:bit beacons and display hot or cold hints based on the distance.

Setting up the radio group

We set the radio group to 1 and all the players use the same group.

radio.setGroup(1)

Is the beacon close?

To determine how far away or how close they are, we use the signal strength of each radio packet sent by the beacons. The signal strength ranges from -128db (weak) to -42db (very strong).

let signal = 0;
radio.onReceivedNumber(function (receivedNumber) {
    signal = radio.receivedPacket(RadioPacketProperty.SignalStrength)
    basic.showNumber(signal);
});
radio.setGroup(1)

Test out your seeker

Test and record the signal values as you move around a beacon, moving closer and farther away:

Cold

The seeker’s screen will display SmallDiamond: if the beacon is far (cold). Use the signal values collected in the previous step to determine when to show each icon.

let signal = 0;
radio.onReceivedNumber(function (receivedNumber) {
    signal = radio.receivedPacket(RadioPacketProperty.SignalStrength)
    if (signal < -90) {
        basic.showIcon(IconNames.SmallDiamond)
    }
})

Warm

The seeker’s screen will display Diamond: if the beacon is relatively close (warm).

let signal = 0;
radio.onReceivedNumber(function (receivedNumber) {
    signal = radio.receivedPacket(RadioPacketProperty.SignalStrength)
    if (signal < -90) {
        basic.showIcon(IconNames.SmallDiamond)
    } else if (signal < -80) {
        basic.showIcon(IconNames.Diamond)
    }
})

Hot

The seeker’s screen will display Square: if the beacon is really close (hot).

let signal = 0;
radio.onReceivedNumber(function (receivedNumber) {
    signal = radio.receivedPacket(RadioPacketProperty.SignalStrength)
    if (signal < -90) {
        basic.showIcon(IconNames.SmallDiamond)
    } else if (signal < -80) {
        basic.showIcon(IconNames.Diamond)
    } else {
        basic.showIcon(IconNames.Square)
    }
})

radio