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Topic: works: MIDI-IN: code + schematics (Read 51302 times) previous topic - next topic

kuuk

ccgibson,
i know about the pain to debug this.
Quote

Some of the steps I've tried:
1) I've verified my input pin works using a simple potentiometer.  I can get Serial.Available to read an input byte with that set-up
2) I've tried both midi plug wiring options as described in this thread.
3) I've tried the circuit with and without the diode.


if you are already getting some serial data, i'd suggest checking just for a "144" (note-on message). Every keystroke should cause at least one.
Code: [Select]


if (Serial.available() > 0) {
   blink(); //once to signal at least something arrived

   // read the incoming byte:
   incomingByte = Serial.read();

   // wait for as status-byte, channel 1, note on
   if (incomingByte== 144){ // note on message starting starting
     // yeaha, we're getting something
     blink();
     blink():
     blink();
   }
}


if you're not receiving any data, you most likely have a problem with the opto setup. are you using the 4n28? can you verify that the optocpupler [still] works?
i'm not sure about your 2-watt resitors, but if they're that big, i could imagine them adding some noise. still i think you should get correct data in one of let's say a 100 key strokes.

remember that you need to set your keyboard (or whatever midi device you'Re using) to use midi channel 1 to use it with this code here.


good luck,
kuk




ccgibson

thanks kuk.

1) I did make sure midi communication was occuring over channel 1.
2) I'm not getting any serial data, so i'm not filtering at all right now.

I have a bunch of 4n28s but I'm not sure the best way to validate it is still working.  Any quick hints?

ccgibson

nevermind!  Got it working, finally!

thanks for all the help.

kuuk


SoundGuyAndy

Does anybody happen to have a copy of the schematic for this? Unless it's just something weird on my end, the image from the original post is missing. Thanks!

davebv

Is there any chance to get MIDI data from the USB directly in osx? thanks!

carkat

thank you very much for this! this works perfectly...

carkat

if you want to make a MIDI-in shield for the arduino based on this schematic you can get layout, parts list etc. there:
http://www.instructables.com/id/Arduino_MIDI_in_shield/

Intosia

#23
Feb 20, 2009, 04:24 pm Last Edit: Feb 20, 2009, 04:24 pm by Intosia Reason: 1
Thanks Carkat, thats the first MidiIn schematic that worked for me! Using a 4N27. :)

Chris L

Firstly, I'm trying to put together my own MIDI instrument, and found this code indispensable -- thanks Kuk!

But, as a programming n00b, I don't really understand the why 'action' is necessary -- would anyone mind explaining that to me, please. :)

Also, just to check -- in the initial code, the blink subroutine (was that the correct term?) isn't used is it?

Again, thanks for the very helpful code.

quackmaster7000

I got a Korg MicroKorg for xmas a while back only to find that it didn't have a sequencer built in :(. So, I've decided I'm going to make an Arduino do some MIDI IN/OUT, and act as a cool sequencer accessory. I'm using a small backlit serial LCD, some multi-color LED bar graph displays, a few HC595's, a large pot, and (possibly) 2 Arduinos. I figure I'll have two Arduinos to make the setup easier to program (master-slave config). I hope to get it to the point where the Arduino(s) will get all key, knob, and other MIDI status messages from the microKorg, and save that info in each step along with the program number (for each unique program sound). It'll then be able to play it back in sequence at a variable tempo. I'll update here if you'd all like!  :)

tep

Hello!

I'm on a MIDI project and this topic was very useful, thanks!

I'm playing around with this code and don't get it working.
All I want is to have the led on when a note is on and the led off when the note is off (no polyphony).
Here is the code:
Code: [Select]
//variables setup
byte incomingByte;


int statusLed = 13;   // select the pin for the LED

//setup: declaring iputs and outputs and begin serial
void setup() {
 pinMode(statusLed,OUTPUT);   // declare the LED's pin as output
 Serial.begin(31250);        //start serial with midi baudrate 31250 or 38400 for debugging
 digitalWrite(statusLed,LOW);  
}


void loop () {

if (Serial.available() > 0) {

   incomingByte = Serial.read();
   // wait for as status-byte, channel 1, note on or off

   if (incomingByte== 144){ // note on
     digitalWrite(statusLed, HIGH);
   }
   
   else if (incomingByte== 128){ // note off
     digitalWrite(statusLed, LOW);
   }
}

}

The problem is that my led goes on, but never off!
Any idea?

Thanks  :)

kuuk

hi tep,
probably your keyboard sends "Note ON w ZERO velocity" instead of "NOTE off". the ones i tested do this.

best, kuk



tep

Thank you kuk, you're probably right.
I tested this
Code: [Select]
void loop () {
if (Serial.available() > 0) {

   incomingByte = Serial.read();
   // wait for as status-byte, channel 1, note on or off
   if (incomingByte== 144){ // note on
     digitalWrite(statusLed, HIGH);
     note=incomingByte;
     velocity=incomingByte;
     if (velocity==0){ // note off
     digitalWrite(statusLed, LOW);
     }
   }
   
}
}

and still no result.
But it's perhaps not the best way to get the velocity ?

;) tep

kuuk

first, your code fragment does not update the value of "incomingByte"... you have to re-read form the serial buffer, like in the first line of your code, to get the next received byte.



plus:
ok, i'm really not into midi right now. but if i remember correctly there was something else to mention:

AFTERTOUCH messages are like NOTE ON (OFF) messages without explictly mentioning which note to play or stop. in that case you have to ON/OFF the _last_ note which was explicitly sent. the code i posted at the beginning of this thread does not reflect this, because my (midiman oxygen) keyboard did not seem to use aftertouch.

keep me/us updated please and good luck.

//kuk

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