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a diy midi accordion

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accordian

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hello guys i'd like to ask for information on this idea I have so far and would really appreciate your input.

so for the key side what i'm thinking of doing is using two contacts one the the lever / arm and one on the hole where the air get to the reeds. and i'm thinking of doing so when the "switch" or the contact points aren't touching it will make a sound. so in theory that's the treble side done however what would you suggest for the bass because I've got an idea of adding the same pads but to the other end but how would I go about getting cables for the treble and bass connected as I would imagine the cables getting caught and ripped in the bellows etc.

thanks guys
 

jozz

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like so (bottom end of bellows):
 

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jozz post_id=52757 time=1511806652 user_id=2600 said:
like so (bottom end of bellows):
can you please take more pictures if you wouldnt mind and if you made it yourself some info on how you did it and tips sorry if im being a pain but at the moment what I said above is just a theory or concept im not sure on what mini computer to use the code etc. my idea is very basic.

thanks for your help
 
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i was thinking of using a encoder chip for a pc keyboard and doing it so that my method of making switches will be given a keyboard character and then from there I can map the keys in the software
 

jozz

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accordian post_id=52765 time=1511810618 user_id=2458 said:
can you please take more pictures if you wouldnt mind and if you made it yourself some info on how you did it and tips sorry if im being a pain but at the moment what I said above is just a theory or concept im not sure on what mini computer to use the code etc. my idea is very basic.

thanks for your help

Sorry, I thought you were only asking about the wire. This is not from a midi system but my internal microphone.

Ive been thinking about this myself for a while, but havent found the time yet.

Here is some useful info about the whole concept:
http://www.instructables.com/id/Make-Your-MIDI-Accordion/

Its about a concertina, so you can skip the part about the push pull on the bellows.

I dont have a complete step-by-step tutorial, but what I gather from your plan is:
- switches put under keys output to arduino
- arduino converts input to chars
- ...?

Some other considerations are from the top of my head:
- where does Arduino output to? what midi device? (look at Step 9 diagram at the instructables link) first make that plan for yourself
- or do you intend to just hook op to laptop/sampler-software with USB? or does Arduino act like a real MIDI device in your intended implementation?
- how many switches will there be? you might need to multiplex the Arduino pins
- do you want a bellows pressure switch for MIDI velocity?
- the bass side has many buttons but very little actual reeds in comparison, so you might want to put a switch on only the main bass notes
- you might also need a system to silence the accordion reeds when playing MIDI, this can be done in several ways not all of them good for the instrument
 
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jozz post_id=52830 time=1511938209 user_id=2600 said:
accordian post_id=52808 time=1511906009 user_id=2458 said:

that makes your DIY project a buy-it-yourself project :)

that sorts the encoding part plus MIDI connector, then all you need is switches
Well that’s handy. Although from looking at some of the diagrams it looks kinda tricky with the pins if you could have a look at the bass switch diagram (i’d Appreciate it)

What I’m unsure of is if the switch diagram shows that the switches need to be connected to 2 different pins on the arduino and if that the case how do I stop multiple bass notes going off?
 

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I think because pins 2 and 3 are identified by something else then just 5V, probably PWM by the looks of it

So the software will read the pins rather than check only if its HIGH or LOW.
 

jozz

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If you're a total beginner then you might want to start first with some arduino projects that are easier and teach you about how the I/O basics work on the arduino.

Essentially, how I see it, the two diagrams show pins 2,3 (bass) and 8,9,10,11 (treble) are sending a certain signal (programmed in the software running on your arduino) over a path to any of the numerous pins listed below. These signals (probably a PWM dutycycle) will identify which pin is sending.

If no keys are pressed all switches are open so all signal paths are interrupted. Whenever a switch is pressed the signal path carries the signal to the receiver pin. The length of the signal will probably also be determined by the software after the switch is released again. This is then collected by the arduino sofware and translated to some sort of midi command and sent over a midi port (which they also seem to sell at that website).

The receiver pins do not matter that much and can be setup in the arduino software as you see fit. The important part is that they are not used for anything else on the arduino. At the start of your program you can claim these and define them as all the notes you are going to translate.
 
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if you don't mind me asking could you please circle on the picture of the board which pins it's saying in the bass and melody as so far i'm just looking at the numbers besides it all and there seems to be a lot

and as for trying an arduino as stupid as this may sound I tried one quite a while ago and did'nt understand any of it which why i'm hoping that when I buy this kit is just get 1 cable going from a pin to a switch and then to the other pin eg. in the bass diagram pin 2 to 14 will be a c.

but if this is correct I have one question if alot of these buttons or keys use the same pin how do I go about doing that. just a splitter?
 

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accordian post_id=52861 time=1511997850 user_id=2458 said:
when I buy this kit is just get 1 cable going from a pin to a switch and then to the other pin eg. in the bass diagram pin 2 to 14 will be a c.

but if this is correct I have one question if alot of these buttons or keys use the same pin how do I go about doing that. just a splitter?

Look at this diagram:
http://3.bp.blogspot.com/-5bIrGV8-T...z6oc-Wg/s1600/ARDUINO.Mega.Pinout.Diagram.png

You see how all the pins have different functiones, but the pink IDE numbers will be used in your arduino software to recognize them. This will need to be setup in your program but the kit will probably already have that.

You are correct in saying that from pin 2 there will be a signal path to 14, interrupted by your switch.

That means in order to get a C bass sounding you will need to have pink pin2 (a pwm pin), send a pwm signal, so that when it is switched, can be read out of pin14.

The same goes for chord C, but now the signal comes from pwm pin3, which needs to send a different pwm signal than pin2, but also to pin14. Now when you readout pin14 you will get a different signal so your program knows it has to generate chord C instead of bass C.

This is how you can readout different things on the same pin.

Now if both switches to pin14 are pressed at the same time, your program needs to add up these pwm signals and so it can distil they were both pressed. So pin2 always sends pwm duty 20 and pin3 always sends 50 if you read pin14 you will get 70 so it knows it has to generate both bass C and chord C.

For this all to program yourself of course you need some experience. But I guess the kit will come with the program installed?

The physical wiring can be made according to the diagram. There is no splitting, the wires from switches C and chord C just end up at pin14 in this case.
 
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Now if both switches to pin14 are pressed at the same time, your program needs to add up these pwm signals and so it can distil they were both pressed. So pin2 always sends pwm duty 20 and pin3 always sends 50 if you read pin14 you will get 70 so it knows it has to generate both bass C and chord C.
There are diodes in the circuit diagrams. The point of them is to only activate one output at one time and have only the switches connected to that output show on the inputs. Otherwise there would be no difference between pressing three buttons on the corner of a rectangle and then pressing the button at the remaining corner. Computer keyboard matrices may get away with skimping on most of those diodes, but polyphonic music keyboards cannot really afford sacrificing reliability when more than two keys are pressed.
 

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Hi,

I really liked those midikits options, but my knowledge is almost zero about these new things like arduino and raspberry and similar. So if I were to try to make something like this to work, I would, and will probably, find a local arduino geek to help me with this part of the job. Not too far from where we live, there are arduino and raspberry meetings, so I'll get there with the printouts and see if someone can help me out. Those geeks are mostly really nice people, and one may be interested with such a challenge.

It would sometimes be really nice to have a silent box to practice. ymmv.
 

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Geronimo post_id=52867 time=1512043614 user_id=2623 said:
There are diodes in the circuit diagrams. The point of them is to only activate one output at one time and have only the switches connected to that output show on the inputs. Otherwise there would be no difference between pressing three buttons on the corner of a rectangle and then pressing the button at the remaining corner. Computer keyboard matrices may get away with skimping on most of those diodes, but polyphonic music keyboards cannot really afford sacrificing reliability when more than two keys are pressed.

Yes, you are right, I wasnt paying attention.

I saw two lines assuming they would ignore further presses.
 

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