Arduino standalone MIDI interupter - Interference issues. / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Arduino standalone MIDI interupter - Interference issues.

previous 1 2

Move Thread

LAN_403

Doug86

Wed Nov 11 2009, 03:01PM

Registered Member #2424 Joined: Tue Oct 06 2009, 08:02AM
Location:
Posts: 17

Right, ive sorted out the pulsewidth issue by using annother timer and interrupt. The sketch works pretty well now. Ive also added pulsewidth limiting.

You need the timer1 library from here

And the MIDI library from here

Let me know if you have any issues with it :)

and if anyone can tell me why it struggles with e4 (Midi number 64 ~ 330Hz) id really apreciate it :p (I suspect it's because the interupt for the pulse width and the main timer are getting in each others way, i should probably swap the timers round as with the 16 bit timer1 i hopefully won't need the divider routine)

EDIT: CODE REMOVED, PLEASE USE IMPROVED CODE BELOW

Goodchild

Wed Nov 11 2009, 04:08PM

Registered Member #2292 Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795

Thanks you very much for the code it is a realy big help for me

Thanks again

Doug86

Wed Nov 11 2009, 04:52PM

Registered Member #2424 Joined: Tue Oct 06 2009, 08:02AM
Location:
Posts: 17

No problem at all :) but try this one.

Just had a total DUH! moment.

All problems solved with much simpler code:

You need the timer1 library from here

And the MIDI library from here

If you want to be able to play higher notes you'll need to edit the second line that says "#define NOTELIM 70 //Highest MIDI note to output." to a higher number USE WITH CATION!

#define OUTPIN  9 //Output pin to drive coil.
#define NOTELIM  70 //Highest MIDI note to output.
#define PWLIM  300 //Pulse Width limit in us.
#define PWMULT  3 // multiplier applied to velocity to get pulse width.


//Include librarys.

#include <MIDI.h>
#include "TimerOne.h"

//Define Global Variables

unsigned int midiperiod[128]; //Array to store midi note periods
unsigned int pw = 20;            //Caurrent Pulase width

void setup(void){
  
  // Prepare Timer1
  Timer1.initialize(1000000);

  // Set the pin we want the ISR to toggle for output.
  pinMode(OUTPIN,OUTPUT);

  //Start up the serial port
  Serial.begin(9600);  



//Define Midi Note Periods
  
midiperiod[0] =122312;
midiperiod[1] =115447;
midiperiod[2] =108968;
midiperiod[3] =102852;
midiperiod[4] =97079;
midiperiod[5] =91631;
midiperiod[6] =86488;
midiperiod[7] =81634;
midiperiod[8] =77052;
midiperiod[9] =72727;
midiperiod[10] =68645;
midiperiod[11] =64793;
midiperiod[36] =15289;
midiperiod[37] =14431;
midiperiod[38] =13621;
midiperiod[39] =12856;
midiperiod[40] =12135;
midiperiod[41] =11454;
midiperiod[42] =10811;
midiperiod[43] =10204;
midiperiod[44] =9631;
midiperiod[45] =9091;
midiperiod[46] =8581;
midiperiod[47] =8099;
midiperiod[72] =1911;
midiperiod[73] =1804;
midiperiod[74] =1703;
midiperiod[75] =1607;
midiperiod[76] =1517;
midiperiod[77] =1432;
midiperiod[78] =1351;
midiperiod[79] =1276;
midiperiod[80] =1204;
midiperiod[81] =1136;
midiperiod[82] =1073;
midiperiod[83] =1012;
midiperiod[108] =239;
midiperiod[109] =225;
midiperiod[110] =213;
midiperiod[111] =201;
midiperiod[112] =190;
midiperiod[113] =179;
midiperiod[114] =169;
midiperiod[115] =159;
midiperiod[116] =150;
midiperiod[117] =142;
midiperiod[118] =134;
midiperiod[119] =127;
midiperiod[12] =61156;
midiperiod[13] =57724;
midiperiod[14] =54484;
midiperiod[15] =51426;
midiperiod[16] =48540;
midiperiod[17] =45815;
midiperiod[18] =43244;
midiperiod[19] =40817;
midiperiod[20] =38526;
midiperiod[21] =36364;
midiperiod[22] =34323;
midiperiod[23] =32396;
midiperiod[48] =7645;
midiperiod[49] =7215;
midiperiod[50] =6810;
midiperiod[51] =6428;
midiperiod[52] =6067;
midiperiod[53] =5727;
midiperiod[54] =5405;
midiperiod[55] =5102;
midiperiod[56] =4816;
midiperiod[57] =4545;
midiperiod[58] =4290;
midiperiod[59] =4050;
midiperiod[84] =956;
midiperiod[85] =902;
midiperiod[86] =851;
midiperiod[87] =804;
midiperiod[88] =758;
midiperiod[89] =716;
midiperiod[90] =676;
midiperiod[91] =638;
midiperiod[92] =602;
midiperiod[93] =568;
midiperiod[94] =536;
midiperiod[95] =506;
midiperiod[120] =119;
midiperiod[121] =113;
midiperiod[122] =106;
midiperiod[123] =100;
midiperiod[124] =95;
midiperiod[125] =89;
midiperiod[126] =84;
midiperiod[127] =80;
midiperiod[24] =30578;
midiperiod[25] =28862;
midiperiod[26] =27242;
midiperiod[27] =25713;
midiperiod[28] =24270;
midiperiod[29] =22908;
midiperiod[30] =21622;
midiperiod[31] =20408;
midiperiod[32] =19263;
midiperiod[33] =18182;
midiperiod[34] =17161;
midiperiod[35] =16198;
midiperiod[60] =3822;
midiperiod[61] =3608;
midiperiod[62] =3405;
midiperiod[63] =3214;
midiperiod[64] =3034;
midiperiod[65] =2863;
midiperiod[66] =2703;
midiperiod[67] =2551;
midiperiod[68] =2408;
midiperiod[69] =2273;
midiperiod[70] =2145;
midiperiod[71] =2025;
midiperiod[96] =478;
midiperiod[97] =451;
midiperiod[98] =426;
midiperiod[99] =402;
midiperiod[100] =379;
midiperiod[101] =358;
midiperiod[102] =338;
midiperiod[103] =319;
midiperiod[104] =301;
midiperiod[105] =284;
midiperiod[106] =268;
midiperiod[107] =253;


    MIDI.begin();                //  Launch MIDI with default options
  


}

void pulse(){
  
  digitalWrite(OUTPIN,HIGH);
  delayMicroseconds(pw);
  digitalWrite(OUTPIN,LOW);
  
}

void loop(){
  
int controlnote;


  
      //Check for availible midi data
      if (MIDI.read()) {
        switch(MIDI.getType()) {        //  Get the type of the message we caught
           case NoteOn:
                
                
                //get note on number and check for limit
                controlnote = MIDI.getData1();
                
                if (controlnote > NOTELIM){
                  controlnote = 10;
                }
                
                
                Timer1.attachInterrupt(pulse,midiperiod[controlnote]);
     
      
                //Calculate Pulse width from velocity and Limit to PWLIM
                pw = PWMULT * MIDI.getData2();
                if (pw > PWLIM){
                    pw = PWLIM;
                
                    }
                    
                    
               
                break;
           case NoteOff:
      
                //Disable the interupt.
                Timer1.detachInterrupt();
                break;


     default:
        break;
    }
  }
  
  
  
  
  
}

Angstrom

Thu Nov 12 2009, 10:22PM

Registered Member #1900 Joined: Fri Jan 02 2009, 06:44PM
Location: Texas
Posts: 29

Thanks, this will be a good jump off point. I have the Diecimilanove Arduino and it will be good to try with it before trying another processor.

I am a little concerned. It sounds like you have tested this on a DRSSTC already... but the code could let the duty cycle get very high - just under 50% for the highest note (max velocity) allowed (90 on the MIDI table). If you sustain that note there could be a problem... right?

Or am I missing the point?

Doug86

Fri Nov 13 2009, 10:48AM

Registered Member #2424 Joined: Tue Oct 06 2009, 08:02AM
Location:
Posts: 17

Hi Angstrom, Thanks for pointing that out, you are correct, I wanted to be able to play the very high notes so left the note limit quite high (I use the sequencer to insure that the pulsewidth (velocity) is very low for the highest notes. I've edited the code above to make it safer for people to test with. At some point ill probably add a max duty cycle limit so the code automatically adjusts the pulsewidth for the highest notes.

Is it worth me making a projects thread for this with the circuit diagram etc?

thanks again.

Angstrom

Fri Nov 13 2009, 02:56PM

Registered Member #1900 Joined: Fri Jan 02 2009, 06:44PM
Location: Texas
Posts: 29

By all means don't wait for permission.

I'm also a little confused here:
if (controlnote > NOTELIM){
controlnote = 10;
}

Did you mean to make it so it defaults to a lower note if the input exceeds the limit? The only reason I can think of is to be safe and let the operator know that it happened.

The code seems far too simple at first glance, but I guess that's something nice about this development board. Maybe you could post a video of it working?

Doug86

Wed Nov 18 2009, 11:54AM

Registered Member #2424 Joined: Tue Oct 06 2009, 08:02AM
Location:
Posts: 17

Hi angstrom,

you're right about the code you quote, it's there to make it obvious that the limit was exceeded.

The code looks simple because all of the midi input handling and timer management is taken care of by the two librarys mentioned in the post.

All the best,

Doug

audio:deviant

Tue Nov 24 2009, 08:01PM

Registered Member #2081 Joined: Wed Apr 15 2009, 11:36AM
Location:
Posts: 78

thought everyone would enjoy a demo with a tried and tested song!

previous 1 2

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob