Aural indication of XBTUSD price movements via BitMEX websocket realtime-trade data. Uses the blues scale to add some funk to your trading. Copy & paste into your browser's console..

BitMEX Jazz BEEP

/**
 * BitMEX JAZZ BEEP
 *
 * Aural indication of XBTUSD price movements via BitMEX websocket realtime-trade data.
 * Uses the blues scale to add some funk to your trading.
 *
 */

var options = {
    symbol: "XBTUSD", // subscribe to trades of this instrument
    largeOrderThreshold: 10000, // only beep on trades larger than
    durationDelta: 750000, // trades of this size beep 1s, smaller trades beep shorter
    durationMin: .05 // minimum time of beep, to reduce jitter
};


// blues scale (pentatonic minor C)
// notes: C, Eb, F, F#, G, Bb
const bluesScale = [
    256.87, 305.47, 342.88, 363.27, 384.87, 457.69,
    513.74, 610.94, 685.76, 726.53, 769.74, 915.38,
    1027.47, 1221.88, 1371.51, 1453.07, 1539.47, 1830.75,
    2054.95
];

var scale = bluesScale;
var key = Math.floor(scale.length / 2); // start with middle key in scale


// WebAudio init.
var beep = (function () {
    var audioCtx = new (window.AudioContext || window.webkitAudioContext || window.audioContext);
    var gainNode = audioCtx.createGain();
    gainNode.connect(audioCtx.destination);

    return function (duration, frequency, volume, type, callback) {
        var oscillator = audioCtx.createOscillator();
        oscillator.connect(gainNode);

        if (volume){gainNode.gain.value = volume;};
        if (frequency){oscillator.frequency.value = frequency;}
        if (type){oscillator.type = type;}
        if (callback){oscillator.onended = callback;}

        oscillator.start();
        setTimeout(function(){oscillator.stop()}, (duration ? duration : options.durationMin*1000));
    };
})();


// WebSocket init.
var s = new WebSocket("wss://www.bitmex.com/realtime?subscribe=trade:" + options.symbol);
s.onmessage = function (frame) {
    var msg = JSON.parse(frame.data);
    if (msg.action === 'insert') {
        for (var i = 0; i < msg.data.length; i++) {
            var t = msg.data[i];
            if (t.size >= options.largeOrderThreshold) {

                // shift key in scale according to tick
                if (['PlusTick', 'ZeroPlusTick'].includes(t.tickDirection)) key += 1;
                if (['MinusTick', 'ZeroMinusTick'].includes(t.tickDirection)) key -= 1;

                // loop scale top to bottom / bottom to top
                if (key >= scale.length - 1) key = 0;
                else if (key <= 0) key = scale.length - 1;

                // calc duration, bigger trades, longer beep
                var duration = t.size / options.durationDelta;
                if (duration <= options.durationMin) duration = options.durationMin;
                duration *=1000;

                // logging
                var dir = (t.side == 'Buy') ? '+' : '-';
                console.debug(`${dir} ${t.price} ${t.size}`)

                beep(duration, scale[key])
            }
        }
    }
};