Turn Any Computer Keyboard Into a Midi Keytar

This keyboard "hack" was inspired from a situation when my band was playing a concert, but we needed a secondary synth. I knew computer keyboards could be used to send midi commands to music production software (such as ableton, pro tools, fl studio, etc), but keeping a computer keyboard on stage would be an eyesore. So naturally, I took a computer keyboard apart and tried to make it a little easier on the eyes, and fingers. Here are some of the features of this midi "key-tar":

-Resistive-touch activated keys

-LED back-lit keys

-Guitar strap friendly!

We will get into what we will need for this project in our next step!

Don't forget to watch the attached video below, if you are unsure about what exactly we will be making!

Step 1: Parts

You will need these parts:

-Several LEDs (based on how many keys you want back-lit)

-Resistors (optional) (values depend on keyboard's voltage)

-Wire

-Screws (with large washers)

-A Keyboard

-Foam-board

-Guitar Strap

You will need these tools:

-Soldering iron (with rosin)

-Paint (with brushes)

-Wire stripper

-Screw drivers

-Hot glue

-Razor

Step 2: Remove Keyboard Keys

Once you've chosen your computer keyboard, its time to start taking it apart! We need to take out all of the keys of the keyboard in order to get to open it up. To take off keys, I suggest using a flat-head screwdriver to get some leverage on the keys so they pop out easily.

WARNING: If you decide to use your fingers, you're likely to chip a nail or sustain a minor injury.

After this mundane step, we will move onto something more fun and technical don't worry!

Step 3: Locate PCB

Lets find the brain of the keyboard. The Printed Circuit Board (PCB) of your keyboard is going to be a bit different than mine. Once you take off the keyboard case and locate it, we will need to find our 5v and ground connections. To find these, find a spare led and poke around to find which connections are positive and negative (LEDs work well since they are in fact Diodes). Or if you have a multimeter you could poke around with your continuity tester.

As I mentioned before our key-tar will be touch activated. This is achieved from the printed "film" that the keyboard presses on. (See pictures). This "film" is made up of two parts and when you press them together, it sends a signal to the PCB about which position was activated. We will use this to make our MIDI key-tar touch activated.

When you have established where your positive and negative power sources are on the keyboard, we can move on!

Step 4: Solder in LEDs

To add a cool twist to our project, we are going to add some LEDs. I only added LEDs to the notes that had to be played for the song we used it in, but feel free to deck your key-tar out with as many LEDs as you'd like (provided there is enough power).

Since the specifics vary depending on how many LEDs you are adding, I'll just go over some of the basics and give you a nice link to a circuit wizard. In all reality when we are working with such low current/voltage it doesn't really matter if we are giving our LEDs a little too much current. Therefore, I didn't do much calculating and just made two pairs of two LEDs in series and my circuit works just fine. But if you would like to get it exact, click on this link. That site should guide you through choosing the correct resistor value and how to wire your LEDs.

To find out what keys we want to add LEDs to, I suggest skipping to the second last step and testing what notes you need. To do this, just activate your computer keyboard as a MIDI input and test which keys make which notes.

When I was finished soldering my circuit, I simply hot glued the LEDs in place. This isn't the prettiest thing, but it works. I would suggest using perfboard if I were to do this again.

Step 5: Cut to Reveal LEDs

To play this key-tar we will actually be playing on the back side of the computer keyboard. Therefore, we need to cut the back panel of the keyboard to reveal our keys! Get out a razor and carefully begin cutting out the plastic so that the LED-lit keys are reachable.

Next we can start making this project look a little more professional with its case!

Step 6: Cut the Front Panel

For our case, we will begin with the front panel. Cut a piece of foamboard so that it covers the keyboard backing. Don't forget that you will need to cut a small rectangle so that the keys are reachable.

When you are finished, set the new front panel aside. We will paint it and screw it onto our key-tar in a later step!

Step 7: Hot Glue Foamboard Backing

Now we will need a cover for the back of our key-tar. Cut a piece of foamboard to the size of your keyboard, and hot glue it onto the keyboard.

Be sure that your LEDs are secured in place, since after this panel is hot glued on there is no going back neatly!

Step 8: Paint Front Plate

Lets get creative and paint our front plate! For my art, I painted the name of my band "JPO" and I added snowflakes since we were playing a winter show. I'd love to see what kind of artwork people come up with, please share your results in the comments of this instructable!

Before you attempt to paint any decals, be sure you add a nice base layer of paint so that your art stands out more.

Step 9: Screw in Strap

To make our key-tar playable for a concert, we will need a guitar strap. After looking at an electric guitar, I found that the best way to add the strap and front cover would be to screw them in with large washers.

Lets begin with finding two rather long screws with wide washers. Then put the washer over the screw and put the screw through the hole in the guitar strap. Find a place on the keyboard where you can take out two screws and add your new screws. Now punch a hole in our foamboard front plate. Finally screw in the guitar strap through the front plate and into the keyboard, ensuring that the front plate is fastened tightly.

Step 10: Enable Computer Keyboard As MIDI

In order to use our new key-tar, we need to change some settings in our audio production software. I will show you how to do this in Ableton Live, but the process should be similar for any other software.

First, lets open Ableton. In the software, hover your mouse over the "options" menu. Then be sure that "Computer MIDI Keyboard" is enabled.

If this does not work, make sure that you selected "Computer Keyboard" as an input in the midi track you wish to use.

Step 11: Play Some Tunes!

Finally, you should have a gnarly custom made MIDI key-tar to jam out with! I hope you learned a little about gadget "hacking" and enjoy your new instrument. If you thought this instructable was great, please vote for me in either the Green Design, Glue, or Epilog Contest. Also, If you are interested in other music related projects, check out my other instructables. Thank you for reading!