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masterkeyboard controller with core-module


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Posted (edited)

Hi all,

after a few years in the corner of my room I want to rebirth my really very old Böhm (maybe Fatar?) 61-key keyboard add a new better looking vintage case (with wood) and offer it some masterkeyboard functionality.

OK here is the story:

In the 70th my elder brother had build up an e-piano (from the Elektor-schematics) into a Böhm organcase (really ugly!!). This e-piano never worked completly and sounded horrible.

In the 80s I needed a midi-keyboard but had no money and so I took this case with the keyboard and added Doepfer LMK2. And there was a really nice to play waterfall-like-dynamic keyboard that works fine - but had no additional controls and since I had another keyboard I didn´t need it any more.

What I want to do:

At first I want some basic controls:

modulation wheel/pedal

pitch-wheel

volume-fader/pedal

sustain-pedal/connector

buttons for prg up and down

a display that shows the program-number

at second:

first let´s look if it works

Yesterday I´ve ordered a core-module-kit from Mike and hope that this is enough for the first steps.

;-) maybe I can add some parts of a broken ADD-two perhaps the display the LED and the incrementor.

Let´s see

clem!

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Edited by clem!
  • 2 weeks later...
Posted

Hi all,

On saturday I´ve got the core-kit-V3 and soldered it yesterday. Looks fine.

Now I have to test it.

But there comes the first Question:

Is it possible to use the connectors J8 and J6 (RD0 and RC1 from the PIC) to connect a testbutton as DIN?

Greetings

clem!

Posted

hi stryd_one,

as told above I want to get some master-keyboard-control-possibilitys. Out of this reason I want to save J5 for the analog pots. I can´t find an instruction of how to connect digital switches and buttons to the core V3. But I wanted to connect an incrementor and 2 or more buttons to make prg and channel changes and maybe s.t. more.

Meanwhile I´ve tested the core - the soldering doesn´t look perfect but it seems to work :-). And the raw-case of the keyboard is ready. Perhaps I will make some pics of the keyboard and the controls at the weekend.

Posted

Sorry, you said it was for testing..

If you want to connect the switches directly to the core but not using J5, you're up for some coding... Are you familiar with C or ASM?

Posted

I can´t say that I´m familiar with it, but I had some contact to it very long ago (68000) - maybe there is somewhere a book. So I can connect the buttons directly to the RCs and RDs?

Posted (edited)

In the meantime I´ve put the wooden parts of the case together. Mios and midimon is up and running on the box and after some connectivity-problems the display from the add-two is working too. I´ve destroyed the contacts a little bit at unsoldering from the Dynacord which is real "german-worth-work" from the 80th.4561_kbkpl_jpg698f4453480546d10996651180

Edited by clem!
Posted

hi all,

I´ve build a little circuit with two ICs so that I can connect up to 16 switches (perhaps an old phone must die for the switches). The incrementor is still working too. I have changed the midibox64.hex to a self compiled one with unmuxed AIN and put a first pot to AIN.

At the first glance it seems to work fine ... but than I turned the pot low - and if the value runs under 16 the display dies and if I turn the pot back to the right I only see a black beam like at the startup. Midi is working correctly. Tried also the oiginal hex and reloaded Mios but that didn´t help. :-(

clem!

Posted

Sounds like you have your pot wired wrong, so that the pot causes a short when the wiper is all the way to one side. Probably you have something like

A----------B

|

C (wiper)

It should be:

A is 5V, B is 0V, and C to the AIN.

I think you may have done

A is 5V, C is 0V, and B to the AIN.

In that case, with the pot all the way down (wiper C next to point A) there is no resistance between 5V and 0V == you have a short == dead core.

Posted

Sounds like you have your pot wired wrong, so that the pot causes a short when the wiper is all the way to one side.

Yes I did that the first time I connected my AIN module, often accompanied by slight burning smell from pot :)

Posted

Yes I did that the first time I connected my AIN module, often accompanied by slight burning smell from pot :)

That's enough about burning pot. We don't wanna give the new guy the wrong impression!!

Posted

mmh - I smell it, too.

but it wasn´t the problem. I´ve checked every soldering and found a missing wire at the lcd, as I told there were still midi-out signals without display showing anything, when I turned pot left.

This evening shot a telephone with a display at ibay for 1 EUR, hope this will work better and I can use the switches and perhaps a part of the housing. will fetch it tomorrow.

Yes the smell gets stronger - it´s the Lötkolben don´t know in english. (soldering-iron?)

  • 2 weeks later...
Posted (edited)

Here are some pictures to document the process.

Here is one of the again working LCD.

Here another one of the place where the dead wingman wheel will take place.  ;)

Here another of the wingmanwheel. I think red buttons and knobs will do it.

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Edited by clem!
  • 1 month later...
Posted

hi all,

meanwhile I´ve made a bottom for my housing out of steel 0,75 mm (pictures will follow) and can begin to place the electronics inside. Perhaps I will change the wingman-wheels to more professional ones from fatar. For the top I will choose a modular concept with min. 5 panel elements first one will be a main control panel for the midibox with LCD, some switches and 1 or 2 encoders, which will be placed in the middle, and second one will be a controller-knobs-panel with 4 pots and 4 switches, (maybe later expanded with another LCD and more pots and switches, the rest will be reserved for later adds ;)

When I thougt about controllers I got the idea that I would like to build an aftertouch-sensor. In an old manual for the lmk3 from doepfer I found that in the early days they´ve done it with piezos.

Is it possible to connect a piezo to the ain and regulate it with a L7805 to 5V?

http://www.datasheetcatalog.org/datasheets/270/9138_DS.pdf

Who has done s.t. similar?

Best regards

clem!

  • 1 month later...
Posted (edited)

hi there,

at the weekensd I had a little time to push the project forward.

Now I have the metal part for the top, but it needs some drilling and milling and some black colour.

Before I can do it I need some good looking buttons and knobs and a red inverse display.

But I have the idea to connect the keys of the keybed directly to the core. I´ve studied the posts of qbas. But my keybed has no scanmatrix but 2 "Sammelschienen", "Ruhekontakt" and "Arbeitskontakt" and I thought of rearranging them, that they work like a fatar scanmatrix. I will cut it in parts of 8 notes one of these can be seen in the schematic.

Will this work? I´m not that firm in electronics can s.o. check this?

Best regards

clem!

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Edited by clem!
Posted

Ok - it seems as if I have, free to the german expression "Versuch macht klug" (trial makes wise), to build a scanmatrix-board as shown in schematic.

Best regards

clem!

Posted

Clem,

I can see no fault with your schematic but, like you, I am not so good with electronics that I trust my analysis 100%. I would do what you are going to do and verify it by building it.

Posted (edited)

Thanks for the reply - not so much people interested here in Direct-Music-Application and Handiwork.

Ok - I´ve done some soldering work with another slaughterd böhm-manual.

This is just a prototyoe - quick and dirty  - shouldn´t win a beauty contest, the inverter is still missing but the contacts work here are some pics:

I will test at the weekend.

Best Regards

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Edited by clem!

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