midi example question

ryanejenkins

Hi there!

I'm working on a musical bench exhibit using the playtronica touch me board. I'm really a novice for the programming side of things and am trying to learn as I go. For the moment I'm experimenting with the 05 midi example sketch and it works pretty well but if possible I'd like to have the sound go off when the usb board is not connected instead of sustaining the last note frequency. Is this possible to make a quick change in the code. Any help would be appreciated!

Thanks,
Ryan

giuliomoro

There is no status check implemented in software just now. If you need it, something can be hacked together. Would pressing the button on the board to stop the currently running program be a useful workaround?

ryanejenkins

Hi thanks for the response! Actually it's built into a stand alone exhibit so won't be able to access the program (it's loading automatically from boot). So basically just need to find a way that after a few seconds, if no note is pressed it doesn't make a sound (now it makes the tone from the last "note" pressed).

Thanks,
R

giuliomoro

I see. And it is expected that the controller will be unplugged during the exhibit? How is your audio program implemented? Do you keep track of active notes somehow?

ryanejenkins

no I'm just using a board called "touchme" made by playtronica as the midi input (https://touchme.playtronica.com/) it measures the resistance between contacts and turns it into a midi note. I have it hooked up to a bench so that when people touch armrests and hold hands the note changes depending on the quality of the connection. The midi example sounds great but the only problem is that the last note keeps playing after the connection is broken so its a drone in case no one plays with the exhibit for a while. If there's a place in the code that could be adjusted to make the midi not sound after the contacts aren't connected for a while that would be perfect. I'm a bit of a beginner for programming (and especially programming sound) so not sure where that is in the code and if it's possible.

Thanks,
Ryan

giuliomoro

I am a bit confused, it seems that the board is not sending "note off" messages? Or maybe it is sending real "note off" messages instead of the usual way (that is : sending "note on" messages with velocity = 0).

In the second case, here is a fix. If you are using just the code from the example, can you update the function midiMessageCallback() so that it looks like this?

void midiMessageCallback(MidiChannelMessage message, void* arg){
	if(arg != NULL){
		rt_printf("Message from midi port %s ", (const char*) arg);
	}
	message.prettyPrint();
	bool isOff = (message.getType() == kmmNoteOff);
	if(message.getType() == kmmNoteOn || isOff){
		gFreq = powf(2, (message.getDataByte(0) - 69) / 12.f) * 440.f;
		gVelocity = message.getDataByte(1) * !isOff;
		gPhaseIncrement = 2.f * (float)M_PI * gFreq * gSamplingPeriod;
		gIsNoteOn = gVelocity > 0;
		rt_printf("v0:%f, ph: %6.5f, gVelocity: %d\n", gFreq, gPhaseIncrement, gVelocity);
	}
}

If this doesn't work, can you please send the output generated on the Bela console?

ryanejenkins

thanks so much! I ended up going with a different solution but I'm looking forward to exploring more with all sorts of coding options with Bela Board and other peripherals - especially playtronica stuff! Check out wonderfulidea.co for updates on our experiments and I'll keep asking questions here when I get stuck! Really appreciate it!