Detecting what note has been pressed on a MIDI keyboard.

[Kinokoda]

I have been trying to find some way to detect what note was pressed but I don't know how to make an if statement for that.

My goal is to find what note has been sent to the Arduino, and then depending on what note it was send an analog voltage out with analogWrite();.

Any ideas?

[franky47]

Check out the Callbacks example, it does just that.

The handleNoteOn function will be called when the Arduino receives a NoteOn, and the pitch parameter will be the note number (between 0 and 127, check out this table to map it to human-friendly note numbers).

arduino_midi_library/examples/Callbacks/Callbacks.ino

Lines 12 to 19 in 2d64cc3

	void handleNoteOn(byte channel, byte pitch, byte velocity)
	{
	// Do whatever you want when a note is pressed.
	// Try to keep your callbacks short (no delays ect)
	// otherwise it would slow down the loop() and have a bad impact
	// on real-time performance.
	}

[franky47]

No, that would depend on the thing you are controlling with that voltage.

Usually on analog synths, there are envelopes (ADSR) that are in charge of opening or closing a voltage controlled amplifier (VCA), which lets the sound pass when the envelope is active (note on) and mute the output when it's inactive (note off). The controlling of envelopes is done with a Gate signal, which you can generate via a digital pin (HIGH = active, LOW = inactive, though some synths use the opposite convention).

Check out the SimpleSynth example, it has the concept of a Gate pin, plus a way to handle a sequence of notes in memory so that you can press multiple keys, the latest one will be the current pitch and only when there are no more keys shall the envelope be released.

[Kinokoda]

Oh okay
Dont worry, I have designed a vca and a adsr envelope generator, thanks for telling me though. Ill close the q&a and again thx for he help.

[Kinokoda]

hey @franky47, about the gate control.
Can I do it just by setting a pin high with digitalWrite and use that as a gate output?

Im talking about gate control

and will the analogWrite override itself?

[franky47]

If your envelope is OK with the Vcc voltage of your Arduino (5V or 3.3V depending on which board you're using), then it should be enough. Otherwise you'd need a piece of circuitry to boost the level (Schmitt trigger, which usually invert their input so you'd have to digitalWrite in the opposite polarity).

Not sure what you mean by "override itself"? Whenever there is a note on, the pitch will be updated to reflect it, but if you were to press a C3, keep it pressed and make a chord with a E3, when releasing the E3 it wouldn't update back to C3, for that you'll need to use the note list code in SimpleSynth.

[Kinokoda]

okay then thx