Trigger to capacitive keyboard

[BillB]

An odd tech question.

Is there any way to use a trigger (in my case from a Behringer RD-6 or an Arturia Beatstep Pro) or short gate, to activate a capacitive touch keyboard? I am thinking of things like the Korg Volcas, and the newish Behringer mini-synths. Some might make quite cool percussion modules, but the only way to trigger them is via midi.

To get a range of synthetic percussion, it would be more interesting to have one synth per note, thus a trigger input would be better than MIDI, which would attempt to play all the notes of a drum sequence, unless there was some very fiddly channelising going on.

So how might a positive trigger signal be connected to a capacitive keyboard to give the effect of it being touched?

[BillB]

I tried Google and came up with limited results. Looks like it is possible but might be too messy to be worth implementing. It’s a shame - some of these mini synths would make good percussion synths - but for the lack of a trigger in.

[nathanscribe]

This sounds like a job for a sampler.

*points at your MPC*

[BJG145]

I haven't really followed this, but you're suggesting that some electronics hack to trigger a cap-touch input would be easier than using its MIDI input? At first glance this sounds unlikely...

...can you explain again what you're trying to do?

(Is this gonna involve a computer? Nothing is very difficult with a computer.)

[BillB]

OK, so I have a Volca keys and VolcaFM2, and I was looking today at the cute little Behringer JT-4000M, a mere £37 at Andertons. If I want the three of those to provide percussion voices in a rhythm track, I can do that via MIDI from a DAW, but only by having a track per voice and assigning different MIDI channels to each device. If I wanted to drive the rhythm without a DAW, from a drum machine or Beatstep over MIDI, it would not be possible, because all 3 synths would want to play all the notes from say C1 to C6, so they would all sound when any of the voices played, in exactly the way that drum machine does not.

What I was speculating about was using the RD-6 (which has 2 trig outs assigned to specific MIDI notes) or the Beatstep (8 gates out) to trigger the micro-synths. So one rhythm track, whether from a drum machine or a DAW, could have the parts assigned to MIDI note numbers, which in turn are converted to triggers, which in turn activate the micro-synths. I already have the RD-6 wired up to trigger a Rakit and an MFB Nanozwerg. It was just extending that idea to little synths that don’t have a trigger in.

But it seems that whilst Google points to at least one example of someone using TTL logic to trigger capacitive buttons, the electronics are a bit involved and therefore, not really worth the effort. I will investigate other sources of synthetic percussion voices - my Blofeld desktop is just waiting to show me what it can do over MIDI.

And Nathan, I take your point about using a sampler, but I like the idea that the synth voices can either be tweaked as the rhythm proceeds, or an LFO can spit out variations of pitch/filter etc for each note, or perhaps long cyclic sweeps. A sampler would be a bit static compared to that.

[ajay_m]

The logical way to do this would be to use something like a Pico pi and add MIDI in and three MIDI outs (this is just using standard serial MIDI which requires only an optocoupler for the input and 3 jellybean transistors (any small signal device) for the outputs). Then with a bit of micropython just transform incoming notes to channels. Much simpler than trying to trigger the capacitive sensors and the cost would be a few quid.

[BillB]

Thanks, Ajay, that does sound like a more elegant solution, although I know nothing about putting together a pico midi device, much less programming one. But I do appreciate that it would be a more sensible way to solve the technical issue than breadboard and bits of tin foil! I might be better off getting the Blofeld to do what I want sonically - I more or less know how to program that!

[Albatross]

Would a midi filter box do the trick? Soething like https://www.cme-pro.com/u6-midi-pro-usb ... xdrpQYa1Nx

[BillB]

Thanks, Albatross, that’s a very interesting box. Looking into it

[The Elf]

I used to apply audio my to my Alesis D4's pad inputs to generate MIDI triggers (I'm going back a long time). I can imagine that anything similar, which has pad inputs, might be capable of the same.

Maybe even gut an old Yamaha DD55/65 or similar?

[N i g e l]

I might be better off getting the Blofeld to do what I want sonically - I more or less know how to program that!

Yes, a blofeld multi is capable of using differnt sounds over different key ranges on the same MIDI channel. It also does velocity splits, so you could have different sounds for accented hits

[BillB]

Thanks, Nigel. Definitely something to explore.

https://www.youtube.com/watch?v=akUa3s2H8aM&t=731

There are also two percussion sound sets / multis available for purchase for Blofeld on the Waldorf website, ‘drum synthesizer’ and ‘attack’, 30 euros each. Can’t help but notice the IOS Attack app is £9.99. It’s a funny world where a full drum machine/synth app is cheaper than a soundset for hardware…

[N i g e l]

werid pricing !

dont forget SOS's synth secrets on drums, the blofeld can handle any/most of them.

cool video.
I note he has assigned the BD to C1, the GM standard. Following the General Midi PERCUSSION Key Map should not be under estimated as it means that in the future you might plug in a [TBD equipment] and it will all just work.