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Fatar keyboard and MIDIbox KB

Mr Tube

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I have an Fatar 88key keyboard type SF, my question is how to connect this keyboard to the controller?

I think the keyboard is different from the modern type keybords where I see a 12 row and 16 lines matrix.

My keyboard have a 22 row and 8 line matrix with alternating contacts, the connection to the controller is with a 40pole flatcable.


The question is must I change the wiring in the keyboard that means adding a lot of Spaghetti, or is it possible to solve this in software settings?

Edited by Mr Tube
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My keyboard is an older model like discribed here:



The Layoput of the matrix looks the same as current range but the difference is 8 lines to the diodes and 2x 11 lines from contacts, in the schematic of the Orla you see that they have changed the input and output function. The newer Fatar keyboards use 16 lines to the diodes and 12 lines to contacts, as dicribed on the Midibox website.


Of course I can change the wiring by cutting the traces and add some wires, where must I made the spit? after 44 keys? there are two PCB's handling 44 keys each

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I don't have a schematic, but it is like this


with the bluelines of the left and right side connected together and reduced to eight lines



how is the scan order with a 88 keyboard

1,2,3,4,5,6,7,8,45,46,47,48,49.50,51,52,9,10,11,12,13 ......?


If the scanorder is like above it is easy to make a splt just by removing the flatcable between the two PCB's plugs and paralleling the rows from the left and richt side.

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Yes! This than should be the same modification I had to do on my TP/100. But there was no flatcable that connects both sides.... so I had to cut the traces :-)

Good luck with your work! :smile:

Did you make the cuttings exactly in the middle? after 44 keys or after 40 or 48 keys

44 is in the middle of a group of 8keys and that is also in my situation.

There are two PCB's with 44 key contact arrangements.

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It has no sense to compare both keybeds. Mine seems to be completely different than yours. 


I just realized that I got you wrong on your intro posting. I thought you wrote, that your keybed has also foilcables... but it's standard flatcable. The TP/100 has 20pin thin foil-cables, which makes the connection to other devices or boards like midibox complicated. 


Anyways: If you are in the need of a new keybed, just send me a PM. I'm in contact with a German distributor of Fatar.

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It is indeed a normal flatcable, a will make a PCB for the controller and I/O in one and connect direct to the 40 pole connector.

On the 40 pole connector there are 8 pins free so I can wire the extra pins for I0-I7, the paralleling of the rows I want to do on the controller board.


Only question is where to split the I0-I7 lines for the left and right side, now it is between key 44 and 45.

That is a little bit strange in my opinion because it is in the middle of row MK5/BK5

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Here a pic of the PCB's connections, it is not my keyboard but the PCB's are the same and also the contacts.




I want to keep the small 20 pole flatcable and cut the traces of I0-I7 and place the 8 wires between the the 20 pole jumper to the free contacts of the 40 pole jumper.


Here the schematic of my keyboard, how the contacts are routed to the 40pole connector is given in the schematic of the Orla keyboard.






Edited by Mr Tube
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See my previous post, I just added a schematic, the orla schematic below let see the connections on the 40 pole connector


keep in mind that the rows   of the groups of 4 keys on the right and leftside are connected together and the blue lines of the left and rightside are paralleled.



Edited by Mr Tube
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I started yesterday with routing of the PCB, with 45x160mm it will find a place in the keybed frame.

I don't use all the IO of the controller, I use only the Midi in out, USB, the connections to the matrix and the analog inputs so I can keep the PCB small.

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I agree with a previous suggestion to make an adaptor board as I have done.


Don't cut any Fatar circuit boards.


This means that you can plug the 40 pin Fatar connector by flat cable into a 40pin connectors on the adapter board. Or maybe to split the cable into two and have more easily obtainable 20 pin connectors (X2). Then using small dia cable make the appropriate connection to two 16 pin connectors.


Therefore the adaptor will have a 40pin connector (or 2X 20 pin connectors)and two 16 pin connectors. The latter will connect by two flat cables to the Dio- Matrix Board. The 40 (or 2X20) pin flat cable(s) will connect to the Fatar Keybed. My keybed has two 20 pin Micromatch Connectors.


You will of course need to source a tool to assemble the flat cable to the cable. I use a cheap tool and a little ingenuity. You also need to source the mating half of the Fatar connector.


A tip. Don't fit this board under the keyboard as I did. It sounds a good idea but you will likely need to remove it for fault finding.


I haven't studied the NG module enough.The following might not be practical.


I have on the adapter board 16 extra diodes which connect to the switches of soft pedal, sustain pedal, transpose, midi channel, presets, panic button and a few others. I have a Fatar 88 note keybed. I use a 12 X 16 matrix. For a velocity sensitive 88 note keybed you need a 176 position matrix ie 11 X 16, To scan 16 diodes requires as well you need 12 X 16 matrix. The Dio-Matrix board will accommodate the 88 note keybed needs plus 80 Diode/ Switch combinations if required.


I use TK's Programming Example 29 with my own program modifications. (Helped a lot by Thorsten) Robin


I should have mentioned that I am using the STM32F40 module. The redesign has just been completed.

Edited by robinfawell
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