Problem Using MIDI Over USB with Arduino Leonardo

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1

Hi,

I have compiled and uploaded the MIDIUSB_write example to my Arduino Leonardo. When I run it connected to my iPad Pro running MIDI Wrench (a MIDI monitor program), I can see the note on/off messages registering in MIDI Wrench. MIDI Channel, Note, and Velocity information is exactly as expected. The Leonardo is hooked up via a powered USB hub to my iPad Pro and my synthesizer.

However, although the MIDI messages are registering in MIDI Wrench, they do not get played by my synthesizer.

There is a feature in MIDI Wrench called Echo everything to all, which broadcasts incoming message to all the MIDI devices on my iPad Pro it can see. When enabled, the MIDI notes do play on my synthesizer.

My guess is that the Leonardo is sending out some sort of generic MIDI message, where my synthesizer (or at least the iPad Pro, or maybe the USB hub) wants the message directed specifically to the synthesizer as a device. I’m not talking about MIDI Channel here; that is set correctly.

So, my question: is there a way on Leonardo to enumerate what specific devices are currently hooked up via MIDI over USB, and then open my MIDI communication on Leonardo specifically to my synthesizer (which should show up as one of the entries in the enumeration)?

I hope this is clear!

Thanks,
Mike

2

No, because it is not the Leonardo end that these things get decided. It is up to your synth to connect to the MIDI stream or your MIDI helper, MIDI Wrench to redirect it.

3

I appreciate your reply! You are correct, Grumpy_Mike; there is no way for this to happen (that I am aware of) without help on the MIDI Host side (i.e, the iPad Pro). There is a program on the Apple App Store called midimttr that will make a connection between two MIDI devices. The program’s description says it’s Bluetooth MIDI, however it works with wired USB MIDI as well.

Thanks,
Mike

4

Now i am assuming that you connect the Synth to your computer via USB as well, But USB is what you computer uses to talk to external devices. Those devices can not just talk to each other without soma service taking care of that. You can use a program like Wrench, or you can set it up through a DAW. If you want to communicate to a synth directly... then just use MiDi :wink: