Tap for Tempo Button

[jean-emmanuel]

I'm referring to this post, which contains a session file and a custom module file, both must be loaded at startup using the server's load and custom-module options. The custom module feature is documented here.

[ccsunmusic]

@jean-emmanuel

here

It works now. Thank you so much for your time explaining it to me who knows nothing about coding!

[nicksaya]

@jean-emmanuel

const MIN_BPM = 40

var tapDurations, tapIndex,
    lastTapTime = 0,
    maxTapLength = 1000 * 60 / MIN_BPM

function reset(){

    tapDurations = [0, 0, 0, 0, 0]
    tapIndex = -1

}

function receiveTap(data){

    var tapTime = Date.now()

    // if last tap is too far (based on MIN_BPM), reset stored value and wait until next tap
    if (tapTime - lastTapTime > maxTapLength) {
        lastTapTime = tapTime
        reset()
        return
    }

    // store tap duration
    tapIndex++
    tapDurations[tapIndex % tapDurations.length] = tapTime - lastTapTime
    lastTapTime = tapTime

    // update bpm
    updateBpm(data)

}

function updateBpm(data){

    // filter tap durations (exclude zeros)
    var durations = tapDurations.filter(x=>x>0)

    // we need at least one value
    if (durations.length < 1) return

    // compute average tap duration
    var sum = durations.reduce((previous, current) => current += previous),
        avg = sum / durations.length,
        bpm = Math.round(60 / (avg / 1000))

    // send bpm back to the interface
    receive('/bpm', bpm)

    // send bpm to the button's original target/address ?
    send(data.host, data.port, data.address, bpm)
}

module.exports = {

    oscOutFilter: function(data) {

        var {host, port, address, args} = data

        if (address === '/bpm/tap' && args[0].value === 1) {
            // update bpm when the interface sends /bpm/tap 1
            receiveTap(data)

            // bypass original osc message
            return
        }

        // process other messages normally
        return data

    }

}

where does this code go? i tried to paste in scrip but does nothing..
sorry if dumb question but i'd love to get this going.. does it matter that your download was saved in old version of OSC?

[nicksaya]

i wish there was a video on creating this

[nicksaya]

can we get a video on how to do this?

[jean-emmanuel]

I'm not the good person to ask, really, I'm not very fond of video tutorials and besides it would take more time than I can spend here to make :). Did you read the whole thread ? I did post that piece of code with pretty precise informations on how to use it.

However it's possible to create a tap tempo button in a simpler manner now, here is a minimal session that demonstrate it with a single button:
bpm.json (3.6 KB)

[nicksaya]

Thanks Got it Working. my confusion was that i was thinking it would change tempo in cubase and wasn't that would actually be bad idea.. Thanks Again!

[denisspycher]

Thanks Jean-Emmanuel... I love these small compact programs.
My question: the taps are limited to max 5. Can this also work dynamically?
That is, the reset comes only when the tab has not been pressed for 2 seconds and not always after 5 tabs?
So you could press 20 times in a row and the result would be more accurate.
or is that already in there?
Because it says in the programming:
locals.n = 5 // max numbers of taps to average

[Nielsen]

Thanks Jean-Emmanuel for providing your new "bpm" example. I've downloaded it to give it a try. I like that it's a much simpler approach to what I've been using.

Question/issues - on my first tap, I get a number readout in the 1000's, then after a few taps the BPM readout seems to be doubled the tempo I'm tapping. I tried tapping a simple 60 bpm to a stopwatch, and the readout displays (+-) 158. Is there a way to adjust or fine tune the readout more accurately?

Thanks again for providing the example file!