From https://makecode.microbit.org , for a DIY toy gun with speaker and PIR sensor

LightGunPIRSynth.js

//
let item = 0
input.onButtonPressed(Button.B, () => {
    pins.digitalWritePin(DigitalPin.P13, 1)
    item = 1
    basic.showIcon(IconNames.Yes)
})
input.onButtonPressed(Button.A, () => {
    music.playTone(440, music.beat(BeatFraction.Sixteenth))
    item = 0
    pins.digitalWritePin(DigitalPin.P13, 0)
    basic.showIcon(IconNames.No)
})
basic.forever(() => {
    if (pins.digitalReadPin(DigitalPin.P16) == 1) {
        music.playTone(pins.analogReadPin(AnalogPin.P1), music.beat(BeatFraction.Whole))
    }
    if (pins.digitalReadPin(DigitalPin.P15) == 1 && 1 == item) {
        music.playTone(pins.analogReadPin(AnalogPin.P1), music.beat(BeatFraction.Double))
        basic.showIcon(IconNames.Square)
    } else {
        basic.showLeds(`
            . . . . .
            . . . . .
            . . . . .
            . . . . .
            . . . . .
            `)
    }
})