Arduino-Controlled Korg PC-1 Tuner

Introduction: Arduino-Controlled Korg PC-1 Tuner

This shall be your guide for hacking into a Korg PC-1 guitar tuner using a Sparkfun SprotoSnap.

The materials you will need are as follows:

Korg PC-1 Tuner

Sparkfun SprotoSnap

Micro USB Cable

Stranded Electrical Wire


The tools you will need are as follows:

Small Philips Head Screwdriver

Wire Stripper

Soldering Iron

Pliers (optional)

Computer (to run Ardiuno software)

Step 1: Disassemble Your Tuner

The first thing we need to do is access the innards of your device. Much of the deconstruction can be achieved with a little bit of force, except for the two small screws located at the underside of the component of the tuner that rotates and contains the LED screen. Remove these screws with a small screwdriver and remove the face of this plastic component. Inside you will find the only circuit board in the device, which contains all resistors, LEDs, and the microphone.

Next, observe the two wires that are holding the circuit board to the 3 Volt battery through plastic casing. You should cut these wires as close to the plastic casing as possible, giving your room to strip the wires back once it is separated.

You may now discard the entire plastic casing, including the 3 Volt battery as you will not need either. The voltage supplied by the ProtoSnap (supplied by your computer) will be sufficient for the circuitboard. However, you WILL need to keep the small, black rubber component that serves as the button for activating the tuner. This will be found resting between the circuit board and the plastic face that you have lifted off. You will continue to use this button to activate the tuner after it has been hacked.

Step 2: Preparing the Arduino Circuit

Before anything interesting can happen, we should setup all the hardware so we're ready to make connections. Attach your ProtoSnap to a location on your breadboard where there is room next to the pins VCC and 13. We will use these pins as connections to wire the Arduino to the tuner's circuit board.

Next you need to cut some wire. Give yourself a liberal amount of length to work with, just to be safe. Next, strip the edges to give yourself some exposed metal and insert one of the tips of your first wire into the niche adjacent to pin 13 on your ProtoSnao. Repeat this process with a second wire, inserting that tip into the niche adjacent to the pin marked "VCC."

You're halfway done with wiring.

Step 3: Preparing Your Tuner Circuit Board

Now that your ProtoSnap is prepared, let's do the same for your tuner's circuit board. You'll notice that there are two wires that are defaultly connected to some terminals on this board. The ones you may want to leave alone are the black and red wires that are connected to the speaker component. The two we want to focus on are those that you previously severed from the tuner's plastic casing as well as it's original power source- the 3 Volt battery.

This is one of the easiest steps: Simply connect the wire that leads from Pin 13 on your ProtoSnap to the brown wire on your tuner circuit board by intertwining the ends of each. Next, connect the wire that leads from Pin VCC to the yellow wire.

Using your soldering iron, solder these two connections.

Finally, we can begin work on the code that will modify what this tuner displays...

Step 4: Constructing Your Code in Arduino

This short code will send the current through Pin 13, into the negative terminal of the tuner circuit board and activate all of the orange LEDs before returning to the ProtoSnap. The delay settings in the code determine the rate at which the LEDs will blink. You may change these settings to manipulate the time for which the LEDs remain on as well as how long they are off in between.

void setup() {

pinMode(13, OUTPUT);

} void loop() { digitalWrite(13, HIGH);


digitalWrite(13, LOW);



After you have a code that will light the LEDs at a rate you fancy, you should plug in your ProtoSnap to your computer via the USB cable.

Step 5: Upload and Test Your Code

Verify and upload your code to your ProtoSnap. You may notice one thing in particular: nothing will happen. This is completely normal.

Recall the small, black rubber component that you saved from inside the plastic case before. This piece is used to activate the circuit and will continue to do so. If you wish to attach this piece to the circuit itself, you can do so carefully with a conservative amount of adhesive at the edges. Otherwise, you should be able to press piece onto the metal plates on the circuit where you first found it and it will activate. Notice that only the 6 LEDs in the center of the circuit activate, with the speeds of delay and duration corresponding to the settings in your code.

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