diyAudio (
-   Instruments and Amps (
-   -   Converting a non-MIDI keyboard (

ShaqueNova 7th August 2012 05:51 AM

Converting a non-MIDI keyboard
Firstly, I apologize if I am in the wrong area as I am new to many things, but very quick to learn. I will try to make my request short and sweet...

Recently, I went for a browse at the local landfill recycling centre and picked up a tattered Base MK-933 electronic keyboard for a few dollars, although it didn't have a MIDI output. It was fully working and very dirty, so I took it apart and cleaned it up. A few wires had come off the circuitry and now it won't work, but it's still a very nice keyboard in a lovely rosewood enclosure with a lid.

Here is what I would like to do with it... since the keyboard is already assembled and the case is sound, I would like to gut out the electronics used for the sound banks and other features, possibly even rebuild the case for just the keyboard to reduce the weight.

And here is my question... I know enough about woodworking to create a fine enclosure and I have the tools for that and electronics, but I don't know much about converting the keyboard to add a MIDI output to use it in my DAW or other standalone software. Is there a simple way of adding circuitry to the existing cables to achieve this? There are 61 velocity sensitive keys and no modulation wheel (which I am not concerned about for the moment).

EDIT: The electronics are fried and in a fit of frustration, I tore out the circuitry, took out the keyboard with its cabling and tossed out the box it was in (it was damaged anyway). I did a little research and discovered that I can use the keyboard PCB and keys to make a MIDI controller at a low cost. I am also currently making a schematic for a lightweight enclosure with holes for MIDI out and a power switch. I still need advice on what would be the best step.

Printer2 8th August 2012 03:11 AM


Is there a simple way of adding circuitry to the existing cables to achieve this?

ShaqueNova 8th August 2012 07:03 AM

Okay, forget the simplicity. I don't mind hard work. What components would I need and how do I go about assembling them? Any link to a "how to" would be appreciated.

geraldfryjr 8th August 2012 07:05 AM

It could be done if you know how to program and build an interfaces for a computer.
You can by a midi controller keyboard that already works for cheap.
But, it does sound like a good candidate for the basis of a DIY analog synth though!!!

If you do some digging in the synth world you might find something.
You would be amazed at what you can find using Google!!


jer :)

ShaqueNova 8th August 2012 02:26 PM

I know how to build a computer interface, no problems there, but I don't understand why I need one. I planned to just link it to my music sequencing software and use the VST plugins.

Analog synth project? That sounds like a great idea. I did some net surfing for what I wanted and stumbled upon a great amount of synth building DIY projects and tutorials and I was pondering on whether I should attempt such a project. Thanks for your input, I will look around some more.

geraldfryjr 8th August 2012 04:09 PM

The reason that you need an interface to a computer is so that the keystrokes of the keyboard can be converted in to numbers and transmitted serially as MIDI data to your MIDI devices.
Even the VST's use MIDI data to control them.
However there are some VST's that can take audio and covert it into MIDI data and perhaps something like that could be used.

For instance I was thinking about using a VST that detects frequency and volume level and run a signal from a simple signal generator through my volume pedal and as the level changes this can be converted to MIDI data to control a VST Wah-Wah or some other effect or by changing the frequency of the generator this can be some data for another parameter for some other kind of VST MIDI control.

So that one input to the sound card will be for my Guitar or whatever and the other input would routed to the VST audio to MIDI data converter.
My sound card has 4 inputs so this could actually give me six sets of MIDI control data using only three of the audio inputs to the sound card.

jer :)

geraldfryjr 8th August 2012 04:22 PM

Velocity is usually done by measuring the time it takes between two switches per key to close.
Each switch closes at a different interval of the keys travel and the time in between the closing of the first switch to the closing of the second switch determines the velocity of the keystroke.

Another reason why it would be easier to use a CPU.
Unless you built a timer for each individual key in which could be done as well and is how you would be able to have velocity and polyphony at the same time for each key.
CPU would be a lot easier and less circuitry involved but either way would work as programming is a pain in my book !! He,he,he

jer :)

ShaqueNova 8th August 2012 05:18 PM

Well, the end result for me would be to use this keyboard like my computer keyboard is used to play the notes in FL Studio (this is all I want to use as I'm not a professional performer, just an interested hobbyist composer). The computer keyboard also uses the same keys as some of the standalone applications that FL uses in its plugins, but I can only use 2 octaves and press no more than 3-4 keys at a time.

What you said makes sense to me, but in between my last post and this one, I spent every minute researching... obviously I'm after the quickest and easiest solution, none of which I am able to find without spending large amounts of money on brain boards. The analog synth idea is way over my head and I've not dealt with electronics for 20 years. You were right that MIDI keyboards are cheap and I'm opt to purchase one.

I really appreciate the things you've told me and I only wish that there may have been a small project for me to immerse myself into just for the fun of it.

geraldfryjr 8th August 2012 05:53 PM

Yes,I agree it is quite an undertaking!!

Here is another idea lets say that you have two very old and slow computers lying around doing nothing,
You could wire the keyboard to the two computer keyboard switches for 4 octaves and the combine the midi outs of the two computers by tying the midi in and outs in series (daisy chained) and run that into your sequencer on one of the computers.

Just an idea I don't know if it would work but it is logical.

Using the idea I gave in the last post you could easily make a monotonic keyboard by feeding the proper note frequency through each key switch and mix them and then feed that into the audio to MIDI converter.

Doing this in a certain way of matrixing it is possible to get some kind of polyphony out of it.
This is the way the earlier analog synths did it.
It is funny just last week I had stumbled on the original Popular Electronics articles on how to do this and how to build a simple synth but I didn't save the link.
I used to have the original prints myself but they are long gone now.

There are lots of possibilities !!
If you just want to enter note data then a simple interface would do it ,But I am no programmer.
Hardware I can do, but not software, it is just not my bag.

Good Luck !!

jer :)

ShaqueNova 9th August 2012 03:36 AM

I slept on the idea and I have another one... there are quite a few broken or non working MIDI keyboards online. Perhaps I could use the MIDI board from one of them. I know what I am suggesting seems futile for my needs and buying a cheap MIDI keyboard would be much more economically viable, but it's the hobbyist woodworker in me that can't shake the need to build something.

All times are GMT. The time now is 08:38 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio