Thanks David, I forgot to check the Preferences since I started to use PurrData.

I am using Purr Data Version 2.3.1 (20170828-rev.aaf525e).
I am not able to output any MIDI. I test this with Snoize MIDI Monitor: PD out is available, but nothing is coming through.Like with this simple sound to midi notes patch

sound to midi.pd

It would be nice to list the libraries you used. I see tons of errors: "...could't create".

I get error

svf~ low
... couldn't create

Pd-0.47-1-64bit on mac

Here, I got it.
You can run an audio track and play MIDI synth along with it by tapping a mic(or drum trigger in my case).
It will be used in dance performance where flamenco dancer plays music by clogging the floor.
It needs some tweaking of sensing parameters though
I am pretty happy with my first real PD project. Thanks, David!

tap notes along.pd

OK, first part is working.
Now for the bonk~

sound play ram to midi.pd

BTW I find sometimes easier to send AllNotesOff CC message 120 or 123 than noteon with vel 0. Specially when you are triggering notes in rapid order(the way I like to with my interactive installations). Even if I use noteOff I put this AllNotesOff in 1sec interval in case some notes get hung.

Thanks. I am learning by doing.
However this method tends to send vel 0 most of the times - noteOFF(test works OK though). I think it receives notes from fiddle~ with velocity 0-127 and at the time of bang it may be at 0 more often than not.
I tried [makenote 127 500] as well hoping that the note number would change only and will be sent at vel127 duration 500ms, but it seems that vel/time from fiddle~ can not be ignored.

As for piezo trigger I need just a single bang. The difficulty is that after a hit piezo will ring some time(about 1 sec) and rather wildly at first and slowly fades out. However the ringing is very jumpy that makes gating difficult. The only solution I can think of to accumulate the peaks at interval of lets say 100ms and ignore the rest.

Hi.
I am working on the project where I need to transpose a sound file to MIDI and adc~ input(piezo) to detect a hit and from that play the currently active note. Like you have a MIDI track running silently and you make the note sound when you hit a trigger.
I have been successful with the transposing part using fiddle~ and could make a trigger with bonk~ but I am not able to find a way to switch the notes on/off. So far the notes are played as soon they are arriving from makenote~.
So how to put a switch between makenote~ and noteout~?
If I could get an advise for detecting piezo peacks as well. Piezo is a bit tricky device. It rings like a bell when hit and some kind of accumulative value to make a trigger would be ideal.

Get yourself this app
https://www.snoize.com/MIDIMonitor/
And check what messages are sent.
For testing I would use SimpleSynth
http://notahat.com/simplesynth/

FM8 can be tricky to use CC for choosing instruments.

Thanks anyway to help me get this to work / whatever the reason was.