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.
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.
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?
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.
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.
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?)
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?
The Aftertouch problem is solved at http://www.doepfer.de/service/LMK3V2_Service.pdf at page 11, a schematic can be found at page 16. Sorry the manual is german only but the schematic is universal
maybe I can add some parts of a broken ADD-two perhaps the display the LED and the incrementor.
