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clem!

masterkeyboard controller with core-module

24 posts in this topic

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!

4713_world_png0fd406e401da2c937bd181b6c1

5791_0a21a4d7a7cc76c1d0db6558d6705930b14

Edited by clem!

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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!

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What are you trying to test? the core, or the switch?

Either way: J5

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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.

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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?

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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?

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Yep, you can do that. You'll need to disable SRIO and AIN mux to use those particular pins, and a timer to poll them.

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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!

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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!

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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.

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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 :)

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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!!

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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?)

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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!

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first pic of the mounted wheels and the whole case without bottom and top4707_wheelassmbl_jpg301bbb43f2969348a0e04709_kbwwhlass1_jpg0fac00b77d5e7b1a0bad5

Edited by clem!

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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!

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Googling and searching this forum for 'edrum' will get you lots of info about peizos and AINs :)

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Thanks!  :)

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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!

5260_8er_matrix_giff77989f8d110162ee8a08

Edited by clem!

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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!

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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.

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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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