help: Midi keyboard controller MKC

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wafer101

Joined: 16 Sep 2002
Posts: 73

10 Sep 2006 2:14 mkc midi controller

I would like to extend the capability of this MKC from the basic 64 key controller
(there is also a 128 key available) to a full 8 octave keyboard...

I know somhow we have to add more 3x8 decoder (74LS138) as to make a grid to cover all 8 octave (full piano keyboard) --- this is the easy part.

the other thing to do is to reprogram the PIC16F84 to include it all

take a look here:
http://www.geocities.com/JDPetkov/Hardware/midikeyb/midikeyb.htm

there you can find a downloadable 64 key ver. the author is not supplying the asm code though but just a compiled one. Haveing the code would be much easyer to expand this project.....

any help...... any idea how to go about?

wafer101

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VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

10 Sep 2006 5:03 midi jdpetkov

The way I see it, the code of the PIC is easy to write. Simply increment PORTA (except RA4, which seems to me is used as the serial output), then read in PORTB, possibly complemented. The key code is then the concatenation of the two numbers: PORTA:/PORTB. Or it can be translated to something else, but that is relatively easy.
Overall, itt should be fairly easy to write.

However, expanding the keyboard means adding more decoders. But as you can see, PORTA has no free lines. So that would make things more complicated. Perhaps it would be easiest to change to another PIC, that has more I/O lines. Then the code can follow the skeleton above, without problems.

What kind of delay can you allow? I am thinking of using a shift register or something before the decoders. Thus, using only 2 or 3 I/O lines on PORTA you could create 8 or more, enough for all the decoders you need to add. But shifting in data serially takes time, that is why I am asking how often you actually need to scan the keys?

The second question is, do you know the codes for such a large keyboard? Would the computer recognize them, or do you need to update that software, too?

wafer101

Joined: 16 Sep 2002
Posts: 73

13 Sep 2006 0:40 midi key codes

take a lookthe at link a gave, there (i forgot his name) the guy gives all codes and full proj. only for 64 key. The pic program he gives is already compiled one. As far as delay It shoud be very small
better if it would be realtime (impossible) but I guess since the pic is running at 4MHz should be good enough to play a VST plugin like FM7 and PRO-53 (keyboards emulators)from National Instrument

Any other expert of pic could give some help....

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

15 Sep 2006 17:25 full keyboard controller fruity loops

I have downloaded the code and I am working on it. The problem is that I am not familiar with MIDI. However, I think there is hope to get it to work, since the current crystal is only 4MHz. If needed, we can bump it up to 20MHz, so timing may not be a problem in the end. I'll keep you posted on my progress.

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

19 Sep 2006 18:05 scan midi keyboard

I have looked into this thing more closely and actually learned a few things in the process (about MIDI and music).
The question I have now is: how many keys do you need? Forgive my ignorance (I never played music), but it seems to me that 128 keys would cover all octaves. And since the circuit already has 128 keys, why do you need to add more?

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wafer101

Joined: 16 Sep 2002
Posts: 73

03 Oct 2006 0:58 source code for scan key piano

Yes vvv you right with 128 key u use all 8 octave full piano. Let's say wind pipe organs use more tha 8 octave.....
The skematic that I included is OK for 8 octave but the file to program the PIC nor the source is made available from the author, I would like to ask any expert to how to write a file for the PIC to include all key. ( the 64 key above link you can get the bin file to program, still not the source for the pic)

Thanks
wafer101

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

03 Oct 2006 17:12 pic midi keyboard

I see. So you need more than 128 keys. I will think about it, but it looks like the "instrument" will have to change the channels, if more than 128 keys are used. This is what I understand from the MIDI documentation. Is that acceptable?
I will continue working on the code, now that I have a better understanding. I stopped since there were no more replies.

wafer101

Joined: 16 Sep 2002
Posts: 73

07 Oct 2006 0:42 midikeyboard pic16f84

VVV thank you very much for your effort, well It would be grat if you could come up with a improved version (more than 128 key) but it would be equally nice to have a source file for the PIC u controller for the included 128 key (above picture).
I am not a u controller programmer otherwise I would try myself, but I could get a lot of insight by understanding the source file that implements this 128 key version.
Again, this file is not made available by the aothor of this project. There is a 64 key compiled version here h**p://www.geocities.com/JDPetkov/Hardware/midikeyb/midikeyb.htm
(not source) available at the link I supplied.

Again thanks a lot for giving it a try.

wafer101.

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

07 Oct 2006 16:36 midi to usb

Hi wafer101,

I have almost completed disassembling the 64-key version and I think I am in good shape to start on a larger project. I could easily modify the code to use 128 keys. It's almost trivial now, but there is no point. However, it would be unfair to Mr. Petkov to publish the dissassembled 64-key code without his permission.

But I am going to start on the larger project, say 512 keys. I can give you the source code for that one, when done.
As I mentioned earlier, just by reading the MIDI documentation, it seems to me that an instrument that uses more than 128 keys could either switch channels, which would make it look like more than one instrument, or it can send a ChangeBank command. I think the latter approach is better.

The only stumbling block right now seems to be the time required to scan 512 keys. I have to see how feasible that is.

wafer101

Joined: 16 Sep 2002
Posts: 73

14 Oct 2006 1:42 petkov midi controller

VVV You right , even more so if someone would be making money off of Mr. P. project as for me I am just a music enthusiast and a bit of an ee (unemployed Sad

) that wants to learn u processors with fun, by building this project and understand how it works. I also tryed to get in tough with Mr. P but no luck........ Let's not forget that outhere there is a lot of scamp going on..... MP3, divx, warez, cracks and even pdf's copyright enfrangments etc... and this people are making real money from someone else work .... we all are potential criminals then....

cheers and thank you for you understanding

wafer101

wafer101

Joined: 16 Sep 2002
Posts: 73

22 Oct 2006 0:30 piano 128keys

I am a bit disappointed in you Mr. Pektov!!!!, I think I just wasted my time talking to you.
I think you just fooled me............
anyway I hope you Well!!! and lotz of money.

cheers

VVV

Joined: 26 Nov 2004
Posts: 1584
Helped: 290

22 Oct 2006 5:43 serbian midi keyboard

Wafer 101,
Check your messages.

stacky2009

Joined: 09 Jun 2009
Posts: 10

19 Aug 2009 10:08 serbian midi keybord

it works very well.i use midi 2 usb conector and connect with fruity loops and i used as a MPC

ron roberts

Joined: 21 Feb 2009
Posts: 2

20 Oct 2009 11:43 help: Midi keyboard controller MKC

Hi VVV
Did you sort the code to use 128 keys? I’ve built the mkc midi controller 64 key version and it works well. But I’m making a Pianola roll scanner and need 90 keys.
Any help would be appreciated.