I am looking to add a set of 20 physical drawbars to my Nord C1 using drawbars taken from a Roland VK77. The set of drawbars is broken down into 2 PCBs, one for each drawbar set. One PCB has a 14pin ribbon cable 2.00mm and the other has a 13pin ribbon cable 2.00mm. I would like to connect these to PCBs to midi board and would like to know which Arduino board can facilitate this and/or what else would I need? I do know I'll need to download the software to change the CCs to accommodate my Nord. The drawbars are on the Nord use 3 different midi channels (1-Upper Manual, 2-Lower Manual, 3-Pedal).
As far as I can see, if you already know the cables pinouts (as drawbars seem to be linear potentiometers, you have 1 pin for each, plus two Vcc&GND) you need 20 analog inputs.
So I think you just need to use 3 SPI interface 8-channel ADCs (e.g. based on MCP3008) and read them in sequence, and as I think drawbars don't need high read frequency it'd be kinda easy coding.
But I have never made a project with those ADC chips, so the only suggestion I can give you is to google around with some example projects using the SPI ADC converters (like THIS or THIS, just as a couple of examples).
PS: I play keyboards in an amateur Genesis cover band so I love Hammonds even if I've never had one, I just use a couple of good VSTs... Good for you, if you have one of the best Nord keyboards!
@straightba11in that's what I thought also, fancy slide faders. CAn you measure or otherwise determine the end-to-end resistance of a single fader?
You could also get the analog values into the Arduino using analog multiplexing and the build in a/d converter on the Arduino.
Either would, it seems, be new territory. Either will be a slog. There are libraries for both approaches. We can help no matter.
I think the multiplexer may be a shade less difficult. Conceptually it may be a bit easier to grasp.
This member had a number of LDRs and interfaced with analog multiplexers. The thread has problems, solutions and ultimatley code and schematics. It may be good fireside (or beach) reading.
She had a few threads, the others may have small details. She threw me under the bus for being, whatever. Just thought I'd warn you, evidently I am not the person my mother hoped I'd turn out to be.
Is out of stock at this link, but it or functionally identical modules should be findable.
With some great trouble (don't even bother but know) any Arduino can do MIDI. Need I tell you what the acronym PITA means?
Any Arduino can be used if Hairless is employed - I've just said more than I know about that which I generlay don't. Caveat Programmer.A
The Leonardo and Pro Micro are both good choices for MIDI. Very easier to start with an Arduino that can do USBHID by design.
I should have mentioned I am VERY new to this world and although I understand some of the terms and concepts, I am starting from ground zero. I do think I will need a multiplexer(?) due to the number of analog inputs needed. If I need to use multiplexers, what does that mean for choosing the main board? Again, any tips would be helpful and I'll definitely keep searching around the web for similar examples.
With an analog multiplexer or as many as it takes to get 20 inputs, your Arduino resources needed would be minimal.
One analog input, and at least digital outputs which would be used to select 1 of 20 to be read at a time.
With 16-1 units like I linked, you'd need four outputs that would feed both muxes to pick 1 of the 16 inputs, and two more to select which of two 16-1 muxes to enable.
So you could actually handle 32.
If you read through the thread I linked you can watch someone else come to an understanding of the idea and see a coherent enough implementation of that idea. Painlessly.
Say if anything you come across doesn't ultimately make sense. It's all fairly straightforward and of course entire loigical.
I am not exactly sure what you mean by that. As stated by others, there are plenty of ways to convert the position of the sliders into value held by variables. There is no real problem to convert those into midi commands of any kind, but what is unclear to me is where and how you want to connect this output to.
a 5 pin midi or a USB computer input ?
MIDI connectors are nothing than a standard serial connection line (but with a specific speed of 31250 as baud rate). You can see MIDI IN connector you have on your keyboard (for this project you need just this) as an "RX" pin, where the device receives data over that serial, in MIDI format.
So just 2 out of the 5 connector pins are used, one for voltage reference (e.g. GND) and the other for data (TX from Arduino, RX to the MIDI IN keyboard).
I suggest you to start reading THIS interesting article about everything you should know about MIDI physical connections. And for Arduino side, there's a MIDI library to make things easier for you, so as soon as you solve your hardware connection between Arduino and your keyboard, you can start having some experience running some of the included library examples.
not on the picture of it, you will need to figure a few more things out using a multimeter.
which wire is connected to which fader
are the fader connected with GND on one end and Vcc on the other or differently
clear and simple, in that case i would go either for something with with an analog multiplexer, and basically i think a board based on a ATmega 328p would be the best (Uno Nano or Pro-mini)
There are no board available that have that many analog pins and unless you can create some kind of matrix (powering sections with a few faders one at a time) a multiplexer or port expander is the way to go.
You should also have a look at control-surface which has special functions for multiplexers and is supported by someone here on the forum.
yeah, i would have gone for a nano or a pro-mini (probably the latter since the usb won't be used) for it's smaller size and the 2 extra analog pins, but yes that sounds right.
