Cheap RollUp Piano with MIDI OUT

jjj · Last edited by jjj on Mon Nov 17, 2008 7:13 am; edited 1 time in total

My mission goes on... Smile

I bought a cheap 5 Oct. RollUp Piano with MIDI OUT, which works at 6VDC. These are great to create an economical Janko, C-system etc. Kbd.
I even have the idea of creating a "uniform zebra piano layout"; i.e. sticking to the ordinary zebra piano layout, but getting the black keys equal-leveled. I truly believe that it is the merely irregular heights and size of the keys, which require years of practice to master all scales and chords.
Thus, uniformity of the Kbd enables us to transfer the fingering from one into other scales and chords.

To trace the circuit and contacts I ripped the silicon/vinyl Kbd apart. It has the usual 8x8 matrix circuit without visible diodes; i.e. the diodes must be within the main chip.

Now I would like to connect an old 120-button accordion bass box onto it. Each button has only one contact.

At first I thought of just using signal diodes to bundle the 3 to 4 tune chords, but I soon realized that the moment a tune goes into another block of 8, one switch won't do the job.

Q: How else could make a chord work with just one switch the most economical way?
Maybe I have to use 4016 or AND-gates ??
I measure 2V7 between the SW contacts.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

I often looked at these cheap keyboards and thought they could potentially make a great portable touch controller ala the EMS AKS or the like. I'm not very well versed in EE, but I wanted to ask, as long as this topic is open-- would there be a straight forward way to convert these keyboards to V/Oct CV gate controller?

If they're set up the same as other Matrix keyboards-- does anone know of a web resource for using Matrix keyboards as cv/gate controllers?

Thanks, sorry to hi-jack topic with (hopefully not too)naive questions.

jjj · Posted: Tue Nov 18, 2008 6:29 pm Post subject:

I think I found, what I'm after, here:
http://midigrid.fullpitcher.co.uk/moreaboutmg.html

Incidentally, it's very much what I had in mind. Something like a page with single, triggerable chords in it.

I wrote MIDIgrid and explained my needs. Not sure if it really works for my purpose? It should, but I don't know how to wire the buttons for MIDI...

MIDIgrid wrote: "It allows the user to create a virtual instrument that plays only the notes or chords required in a particular improvisation session. These can then be played with a mouse or triggered from an external MIDI device".

As the bottom of this page ( http://www.drakemusicproject.org/makepage.asp?page=4cPS-MG ) shows, if I use MIDI control I have to buy another rollup piano and wire it to the 120- button of the accordion accompaniment (and set it on another MIDI channel), because it's impossible triggering MIDIgrid chords from the same rollup Kbd I play the melody. Or is there another way?

You might well know how it's done. That would be of great help. Certainly easier than to go into massive wiring...
For decades I try to realize my dreams. Now it's about time I make it or I have to continue my mission in next life! Smile