Converting Non-MIDI Keyboard to MIDI-Compatable

I am trying to save some money by modifying a non-MIDI keyboard to transmit MIDI data. I did some rather extensive web browsing but found nothing conclusive. Any help would be much appreciated.

What kind be teh keyboard?

Given how cheaply you can get a MIDI keyboard these days you aren't likely to save much if any money trying to mod a non MIDI keyboard to transmit MIDI, and even if you can convert one you'll likely only get it to send MIDI note on-off and not much else.

^ what he said

The keyboard is a Casio CTK-50. And I am willing to accept only having on/off function with the keys, because I will be using it mainly for triggering samples.

Go buy a Korg K49 or something along those lines. You'll be far happier with it than spending what may be an equivalent amount of money trying to MIDI a Casio.

+1:thu:

Hence my first question. Much more troublesome and expensive to retrofit your old keyboard for MIDI than just buying something that already has it. Go for the other suggestions. There are many cheap MIDI keyboards out there. If you had something non-MIDI that was worth adding MIDI to it (e.g. a classic synth or something), that would be a different story. Adding MIDI to a Casio CTK-50 is a complete waste of time and money.

You can find very inexpensive midi keyboards these days, especially on eBay. The time and hassle it would take to add a midi retrofit to a crappy old Casio isn't worth it at all.

Well, as far as wasting time, that's for me to decide. It doesn't seem as though it would cost too much money to convert it. As far as I can see, the most expensive piece would be the midi-to-usb cable, which I would probably end up buying either way. Apart from that cable, it seems as though I would only have to buy a chip or two. And I don't mind "wasting time" figuring this out; it's something of a hobby of mine.

I guess the first thing I want to know is if it is even possible to modify this type of keyboard to transmit midi data.

It is a waste of time because it means you'll have to reverse engineer what's in there, and that's pretty much undoable unless you're a hero with embedded code, a soldering iron, and a pretty big analyzer. There's no guarantee it's going to work and there's no guarantee that you'll keep it in one piece. Circuitbending would be a nice option, but won't give you MIDI, just weird sounds.

If you're still not convinced of our warnings (do return after your experiment to say if it actually worked!), then the part you have to find is called the keyboard scanner. It basically polls every single key at high speed and tries to find out if it's depressed or not.

If that's the case, it'll send the signal to the actual sound engine. However, in most synthesizers, whatever does the keyboard scanning also handles the interface scanning, so every time you press a buttong you get a signal, too. If you just want to MIDI-fy it, you have to find out where exactly this happens so you can ignore those signals.

After finding out exactly how this takes place and having a way to tap off the keyboard scanner, you'll have to get some hardware (which you'll have to program yourself; hope your knowledge of Z80 or 8051 assembly language is still fresh) to convert that into a usable signal that sends MIDI note on/off data. That's the theoretical part behind it. Chances are that at that point, the effort and time you've spent on it could've been used to buy a brand new controller keyboard. Two of 'm.

Last, but not least, Casio keyboards are pretty unspectacular in terms of keyboard feel, so that shouldn't be a reason to do it. If you're going to hack away at it, make it so that you can send MIDI in there, too.

Otherwise, save yourself the pain and get this: http://cgi.ebay.com/M-AUDIO-Radium-49-USB-MIDI-KEYBOARD-CONTROLLER_W0QQitemZ170122884121QQihZ007QQcategoryZ41784QQssPageNameZWDVWQQrdZ1QQcmdZViewItem or something like it.

Must.... resist..... urge to make corny joke....

hahahaha

does sound like a rediculous amount off effort bt still possible ...still rediculos amout of effort

Except for separating the keyboard and the interface, what would you suggest? Keep in mind that even a Z80 can run at 1Mhz. You scan 64 keys (actually 61 but multiples of 2 work well with processors). You could have the entire keyboard scanned in 64/1000000 second - just add on a few clock ticks if it has to send a message, no problem - and if you sense 2 keys playing after eachother the delay is still not noticeable, because it takes millisecond delays for that.

I'm pretty convinced that after decades of years of research doing it like this was the cheapest and most practical solution .

More power to you if you have that much time on your hands. I would rather spend the time making music or just chilling out. I sincerely thing you'll save time and money by avoiding the retrofit avenue.

Well, if programming is involved, it is probably out of my knowledge range.

I was thinking it would only take a few data sheets on the various chips in the keyboard to find an output that i could draw MIDI data from.

The keyboard itself won't have an "interface" chip you can talk to; It's nothing more than a whole lotta switches. Typically these are connected to I/O pins on a microcontroller that's progammed to know what to do with it, and that's likely how your keyboard is designed now. The problem is that there's unlikely any other visiblity of the keyboard activity outside of that board's MCU, so there's nothing to "draw" from. You'll need to replace the MCU code with your own, and that's just the start. You'll need to find a USB "device" interface chip (as opposed to a "host" interface chip), figure out how to interface that to the MCU, then write code that drives that chip.

Then there's the fun of coding MIDI over USB. You'll have to be familiar with the correct USB device class interface so that the PC know how to work with it.

All in all, probably a lot of fun, but very time consuming. You could buy a new MIDI controller for cheaper than it would cost you to build one. But I understand the appeal of wanting to do it yourself!

If it is a non-MIDI keyboard, there is no chip that produces MIDI data.

Something like this is what you would need to build.

http://www.doepfer.de/ctm.htm

It takes 64 on/off switches (like keyboard keys) and converts them to MIDI Note On messages. You must have the software to read the switch inputs and convert them to the MIDI software specification. This module does not give you velocity information. So, when you hit any key, the volume will always be the same.

You will have to take a wire from every key (up to 64) and wire each one to this module.

Moog makes just what you need!

http://www.zzounds.com/item--MOOPIANOBAR

The PianoBar shines laser light on the keys and then reads the position of your hands.

Enjoy spending $1000 to make your crappy $50 Casio midi-fied.....

Yes, it can be done so you will have midi in,out & thru. But then you will still have that 6 min auto shut-off to deal with....Just buy a used Electribe with stereo audio input & play thru elecrtibe FX chain to unit's midi out connected to something you want to controll, but you might have to use knobs on electribe to control changes...Cheers:

To convert your keyboard to a midi-board you first have to go STUFF YOU ALL PEOPLE WHO SAY IT'S NOT POSSIBLE OR TOO EXPENSIVE. Now that you have let that frustration out, you may continue. Let's think outside the box here and say, do we have to do that? Or is there another, better, way. A way that would also allow you to still use your keyboard normally as well. Well I believe that yes, yes there is.

You could plug a 3pin cable into your keyboards headphone out and your computer(preferably a laptop)'s microphone in. You could then get some sort of realtime audio to MIDI converter (I'm sure someone on the internet could make one :-) ) that makes a virtual MIDI device using input from microphone. Then use your standard MIDI software to use this data. What do you think?

If anyone finds or makes some realtime audio to MIDI software, please post back.

Why the hell would you be sure of that...

However, if the Casio in question has a patch that allows you to play straight sine waves, this could be a slightly easier degenerate problem DSP-wise, although latency would potentially still be an issue.

I think it would be cheaper and better to just get a MIDI keyboard in the first place.

My buddy got a used studiologic 5 octave controller off ebay for fifty bucks. No kidding.

Just sayin'.

Absolutely! And here is a great place to study more than you'll need to know.

But, if I bought every $20 Casio or Yamaha PSR whatever (with MIDI) that I see @ Goodwill or on craigslist, my basement would be full(er). As it is, I probably wouldn't drive to the next town for another free one.

Now, someday, I'd like to MIDI my Hammond. Some might say that's a waste of time too, but I just like the feel of them better than anything else. Can you say that about your Casio?