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Topic: works: MIDI-IN: code + schematics (Read 49 times) previous topic - next topic


Aug 19, 2009, 04:22 pm Last Edit: Aug 19, 2009, 04:23 pm by Titus Reason: 1
this code:
Code: [Select]
midi messages start with one status byte followed by 1 _or_ 2 data bytes, depending on the command

example midi message: 144-36-100
  the status byte "144" tells us what to do. "144" means "note on".
  in this case the second bytes tells us which note to play (36=middle C)
  the third byte is the velocity for that note (that is how powerful the note was struck= 100)

Well, that was what I wanted to hear!!!!!!!
"http://highlyliquid.com/midi-accessories/midi-connector-inline/midi-jack-inline.jpg is the same, and the other is MIRRORED"

So we will try that :D

Good luck debugging your things. If i can help(new to midi, but debugged quite a lot of other things. Robotics....

You saw the 36.
Strange that NO ONE mentioned it :O
it is a darn error, I think it is THE error why people weren't getting their stuff to work!


How would this be wired with a 4 pin optocoupler?
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Old soundcloud page (ran out o


Aug 21, 2009, 03:16 pm Last Edit: Aug 21, 2009, 03:19 pm by Titus Reason: 1
Hi every one,

Today I debugging Andreas his schematics etc.
We made good progress, but got stuck later on.
As mattgilbernet said:

'm also having trouble with this. I've confirmed that midi is coming through the jack by removing the opto-isolator and putting an LED between pins 4 and 5 of the jack. I've confirmed that something is coming through the opto-isolator disconnecting RX and instead putting an LED between +5 and pin 5 of the opto-isolator. It flashes when I hit keys. Ive tried 38400 baud as well. The Arduino is just not receiving the Serial in RX. I've at least narrowed it down, can anyone provide any tips or things to try?

the LED tests show that everything is working, or at least signals are being passed, all the way up to Arduino's RX pin. At that point the Arduino seems not to recognize the signal.

We tried sending serial data from the pc to the arduino, and that worked. Arduino was able to receive that.

So the big question is:

WHY is arduino not receiving the serial data from my midi signal?
(p.s. the code never gets past the "if (Serial.available() > 0)" part)



take a look at the schematic of the optocouper's inside on page 1
Your optocoupler has no pin 3 and no pin 6 is my guess
so you'd  only need to skip the 100K Ohm resistor to ground.
The rest is the same
GL Titus


Hello everyone,

As Titus stated in the last post; we still have some problems with the RX of my Arduino.
I have an Arduino Duemilanove.
I use this with a M-Audio Uno Usb to midi device.
Also I downloaded MIDI OX to check whether my outputdevice works.
This works.

Everything works accept the incoming signal through the RX.
What are we missing? Are we using the RX pin correctly?
Can we use the usb-port as the poweradapter at the same time of the RX use? The usb is not connected to the PC, only to a AC adapter.

Thanks in advance,



(to titus)

Okay, thanks.

I hope to sometime make an animusic-ish thing.
Soundcloud page: http://soundcloud.com/beefinator-2
Youtube channel: http://www.youtube.com/user/beefinator14
Old soundcloud page (ran out o

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