Add MIDI Port to Keyboard





Introduction: Add MIDI Port to Keyboard

About: === === ===

Having a MIDI keyboard will let you control digital audio workstations (DAWs) like Pro tools, FL Studio, Ableton Live, etc. As well, it will connect to a wide variety of MIDI gear such as table top synths.

This tutorial is useful for those who already have a non-MIDI keyboard, and want to upgrade it for music production use.

Step 1: Watch the Video!

Here is an 8 minute video with closed captioning that demonstrates all the steps below from start to finish!

Click here to watch on YouTube

Step 2: What You'll Need

  • 1 Arduino UNO, or any Arduino alternative
  • 2 Serial to parallel shift registers
  • Resistors (1 220Ω for the MIDI port, and 6 10kΩ for pull-up resistors - this will depend on step 4)
  • 1 Proto board
  • 1 Female MIDI port
  • 1 Male pin header

And the tools we'll need are breadboards, breadboard jumpers, a multimeter, soldering equipment and wires.

Where to buy

Soldering gear:

Prototype gear:

Step 3: Open the Keyboard

Open up the keyboard, and snip off the ribbon cable from the main board that goes to the keys.

Step 4: Figure Out the Scan Matrix

Put the multimeter on continuity (or resistance) reading. Attach the probes to two pins at a time and sweep the keyboard to find our keys.

For my keyboard, I have a 17 pin ribbon, which I concluded to be a 6x11 scan matrix. To fit all the keys on the Arduino UNO, I'll be combining 11 pins into 3 using 2 shift registers. Then our total input pins is then reduced from 17 to 9.

(The result of this will be different for every keyboard but the procedure will be the same)

Step 5: Setting Up First Shift Register

We'll start with the first shift register.

Wire up the ground and voltage pins as seen in the picture.

Then plug in our Clock, Latch, and Data lines and plug it into the digital pins 8,9,10 of the Arduino. Then we wire up the voltage and ground from the arduino to the board.

Run the first bit of test code from the image. Taking our voltmeter to measure the output of each of the data pins, we should 0 voltage for pins that we are shifting out a 0 and positive voltage for the pins we are shifting out a 1.

Step 6: Daisy Chain Second Shift Register

Once we have our first shift register working, we're going to daisy chain our second one.

We'll wire up the voltage and gnd just like the first one, then hook up the additional data pin of the first chip to the Data pin of the second chip. Then we'll also need to hook up Latch and Clock pins of the two chips (see image).

Now we plug in our Clock, Latch, and Data lines again same way as we did before, and make a small change in our Arduino program to accomodate for the second shift register (see image).

We should see the same alternating pattern with our data pins from this program throughout all of our data pins.

If you're wondering which chip comes first, then simply shift out 8-bits of 0's and 8 bits of 1's at a time and check which chip is outputting the signal.

Step 7: Setting Up Resistors

Hook up the power to our second breadboard.

We're going to extend the first 11 of our data pins from the shift registers to the second board (see image).

Then we're going to bring 6 lines into 6 digital pins of the arduino.

We'll need to add a 10k ohm resistor to ground for each of these lines so that we have a pull-down resistor configuration. This will guarantee that we have the signal we want when the switches on the keyboard are open.

Step 8: Pull Up or Pull Down?

One thing to note, if this direction of current doesn't work for your keyboard, we can switch over to a pull-up resistor configuration by simply doing the following (see the image):

  • First we remove the voltage and ground connection to the shift registers.
  • Then we connect our 6 resistors to positive voltage instead of ground.
  • And we also want to keep the shift register pins connected just the way they are.
  • This will create the pull-up configuration you see in the diagram.

Step 9: Add the Keyboard Ribbon

Plug the cable ribbon into place, matching the rows and columns of the scan matrix.

Step 10: Setting Up MIDI Port

We're going to wire the serial output pin of the port to the serial output of the Arduino, which is pin 1 for the Arduino UNO.

Then we wire up the ground pin and voltage pins like the diagram.

Step 11: Upload Arduino Program

Download the full Arduino code from GitHub (choose the correct version; pull-up or pull-down).

Watch the video from Step 1 at 4:30 - 5:45 to review any necessary changes you need to make to the code in order to get it to work with your specific configuration.

Step 12: Testing

To test our keyboard, we'll plug in our MIDI port to the computer and fire up a MIDI monitor program like MIDI-OX.

We'll hit all the keys to make sure we have everything wired up correctly.

If you don't have a MIDI port, you can get get one of these MIDI to USB adapters (see image) for a few bucks.

Step 13: Transferring to Proto Board

Once everything is working, we're going to transfer everything from our breadboard to the proto board and solder in all the connections.

Plug our wires into the Arduino just the way we had it before, and use the male pin headers here to lock them in place.

Step 14: Putting the Keyboard Back Together

I then traced over the shape of the MIDI and USB ports onto the keyboard case and cut out the hole.

I added a few popsicle sticks to support the Arduino and proto board and hot glued them in place.

Step 15: Final Testing

Plug it in, fire up a DAW, and give it a try!

That's it!

If you liked this instructable, then perhaps you'll like some of my other projects!

You can check them out at Blogspot, or visit my YouTube Channel.

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7 Questions


I did this to a kawaii fs640 61 key 8x8 matrix keyboard using one shift register and my keys are not in sequence how can I fix this?

Can I skip the midi port and get the keyboard input to my PC via Arduino USB port?

What would I do if I had two keyboard ribbons?


Its the same. For example If you have two ribbons with 8 cables each, just think you have one ribbon with 16 cables! :D

Its even easier than having one ribbon! For example if you have two ribbon with 8 cables each then you have 8x8 matrix like me. :) In many cases one ribbon stands for input that should connect to your 74hc595 and the other one stands for output and must connect to your Arduino pins and ground!

Another example: If you have If you have two ribbons with 9 and 4 cables each, Then your matrix goes like this: 9x4 or 4x9!

Best regards.

It works fine on my computer and all of my DAW like Cubase, Mixcraft and...

But when i connect my Arduino Usb cable to my computer (Only for power cause i'm not using batteries) and my Usb to midi cable to my phone, My midi keyboard does not produce any sound, I use many different apps like Midikeyboard, Perfect piano, Midiscope, Walk band and etc... But it doesn't works...

What is the mistake?

Note: My phone supports midi keyboard and running on android 6.0.1.

How can i build a key matrix

I noticed that your keyboard had a USB type B port in it, Can you make a tutorial that just adds in a USB port and skip the MIDI middleman?

thnx for informatoin about how to give a new life to an old Casio keyboard.))

will you add the velocity and aftertouch to this instrument?


Can i make it without the shift registers?
i have a 8x4 keyboard matrix so i have enough pins on aduino.
what have i do with the arduino software?
i just erase the sift register part

1 reply

Hey, dude! Did you made it?
I'm doing it with an arduino Mega, so i have enough pins, but right now i'm kinda stuck figuring out the code.

hi, I'm trying to do this with a Casio keyboard CTK480.

But I'm not getting, help me?

I have a pull-up 8x8 matrix.

I used only one 74HC595.

I changed the codes ...

But when I press a button detects the Synthesia 8 keys. I do not know how to solve.

2 replies

Change scanColumn method like this maybe solving your problem:

void scanColumn(int colNum)


digitalWrite(latchPin, LOW);

shiftOut(dataPin, clockPin, MSBFIRST, bits[colNum]);

digitalWrite(latchPin, HIGH);


I'm having the same issue :/

How different will the circuit look with only 15 wires in the ribbon cable?

Does the keyboard still need to be powered (either by batteries or external cable) or is the arduino powering it?

1 reply

I would think that it is the arduino powering it because you disconnect the original power cables from the keyboard.

can we use a usb b type port instead of regular midi port for the project ... ???

Good job !
But now can you play the piano without the MIDI connected?

4 replies

not if you follow this tutorial. would be nice to see one where they dont destroy the local playback functionalty

Well, it's not destroy, but superseded. You could have a switch and two ribbon cables and call it a day.

Easier way is to just re-use the built in matrix. When the keyboard is on the Arduino can tap and listen to the signals on both sides of the matrix. Just mute the keyboard when using it this way. If you use USB Midi as the output, then you'l have enough pins for all the keys without shift registers.

Well, you'l have enough pins if they keyboard has less then 50 keys.

Is anyone aware of a projects to do the reverse of this? In other words, adding a MIDI input to old keyboards (like an old Casiotone) so you can trigger the keyboard's own sounds from another MIDI source?

Good Project!

I tried to make it in a toy piano but it has some resistors to difference the keys. I don't understand how it works. Do you have some idea?

I add an image with the circuit

Tank You very much!


i have a question. Im trying to make a footswitch for controlling abletons record stop and start. im trying to make a usb 1 button switch. i was wondering if you could give me any advice or direct me in the right path. thank you for all your help. ive already used ur video to make a midi drumset out of my xbox 360 rock band set. any help would be greatly appriciated. thanks again

1 reply

Easier way I could think of:
Get a leonardo or sparkfun pro micro (or any clone therein) and take a look at the keyboard examples in

Actually yes, but if you're going small, I'd suggest you use something like a teensy or a Sparkfun Pro Micro.