Setting up a Guitar

This guide assumes that you know how to solder, if you do not stop now and go practice soldering.

If you have no idea what a microcontroller is, start here. If you are familiar with microcontrollers and pcbs skip to choosing a microcontroller.

A microcontroller is a small board that can be programmed to perform various functions. In this guide you will be using the microcontroller to replace the main board of the guitar. Around the edge of the microcontroller, you will see various solder through holes called pins. These are labelled with a pinout (which you can find by googling {your microcontroller} pinout) and sometimes on the microcontroller itself. The pins have various functions, but for this controller mod you will need to be familiar with 4 kinds:

• GND (ground) - the common connection that all electrical components must connect to in one way or another in order to complete the circuit. Every set of functions for the guitar will feature a GND pin. On the Pi Pico, you will also see a AGND pin. This is also functionally just another GND, however it is recommended to use this for analog inputs like a stick or whammy.
• V_CC (common collector voltage) - this is where you would connect to provide power to a circuit. Sometimes this pin is labelled as 5V, 3.3V or 3v3 on the microcontroller or pinout.
• Digital Pins - These pins are the "basic" pins. They can essentially only show if a button is pressed or not pressed. You will use these for strum, start/select and frets. The are the most common pin on your microcontroller and are usually labelled with just a number.
• Analogue Pins - These pins provide a range of values rather than just on and off. These are the pins you will need to use for whammy, tilt (when using an accelerometer), or your joystick. Analogue pins are labeled on the pinout with A followed by a number.

If you are unfamiliar with microcontrollers, you may also be unfamiliar with PCBs in general and figuring out which pins correlate to which function. Here are some terms you will need to know.

• PCB (printed circuit board) - the often green or brown boards containing traces and electronic components
• traces - the copper conductors on a board. They look flat and are often metalic. Think of them as "wires" on the board itself connecting components. If you are still confused, a quick google can help you understand traces.

1. If it is not labeled on the motherboard, you need to figure out which pin (or pins) is GND. If you remove the membrane, you will be able to see which pin connects to both start and select by following the traces - that pin is GND. (if there are multiple "grounds" they may be labeled as col, or column) Marking GND with a sharpie or using a differently colored wire is reccomended. If you are still unsure, the multimeter can help you confirm if you have the wires correct, as it will beep when you hit a button and have the correct wires. There are examples of the 360 WT and WiiLP above.
2. Connect the common ground to a GND on the microcontroller. If there are two ground wires, you can twist them together and put them in one ground pin on the microcontroller. This will sometimes be necessary when using a microcontroller that has a smaller number of pins.
3. Connect each button to an unused digital pin on the microcontroller.

1. With most whammy's there are 3 pins. (if there are 4, you do not need the fourth. 2 pins is discussed below) The middle pin is the data pin, one outer pin is V_CC while the other pin is GND (it doesn't matter which one, you can flip it when programming later if needed). Whammy needs to go to an analogue pin.
2. Connect V_CC and GND to the microcontroller. (the two outside wires)
   • If your whammy is not responding correctly in game, you may need to swap V_CC and GND around.
3. Connect the data (middle) pin to an analogue pin on the microcontroller. These are labeled with an A on the microcontroller.

If you are working on a controller with only "2" pins as shown below, you will need to desolder the bridged pins and run 3 wires yourself as noted above for the whammy to work best with the configurator.

1. With most pickup selectors's there are 3 pins. (if there are 4, you do not need the fourth. 2 pins is discussed below) The middle pin is the data pin, one outer pin is V_CC while the other pin is GND (it doesn't matter which one, you can flip it when programming later if needed). Whammy needs to go to an analogue pin.
2. Connect V_CC and GND to the microcontroller. (the two outside wires)
   • If your whammy is not responding correctly in game, you may need to swap V_CC and GND around.
3. Connect the data (middle) pin to an analogue pin on the microcontroller. These are labeled with an A on the microcontroller.

If you are working on a controller with only "2" pins as the RB Precision Bass, you will need to desolder the bridged pins and run 3 wires yourself as noted above for the pickup selector to work best with the configurator. For the Precision Bass this is easiest done by desoldering the PCB attached to the potentiometer, and then running your own wires directly to the potentiometer.

1. Connect one pin of the first tilt sensor to ground
2. Connect the other pin of the first tilt sensor to a pin on the second tilt sensor
3. Connect the other pin of the second tilt sensor to a digital pin on your microcontroller.
4. Affix the sensors to your guitar. You will need to play around with their position to get them to activate at the exact point you want tilt activating.

1. Connect GND to GND
2. Connect V_CC to V_CC
3. Connect the signal pin to an analog pin on your microcontroller

1. Connect GND to GND

2. Connect V_CC to V_CC (note that this is a 3.3v device, so for 5V microcontrollers make sure your ADXL345 breakout has a voltage regulator onboard)

3. Hook up SDA and SCL to the microcontroller

   Microcontroller	SDA	SCL
   Pi Pico (Recommended)	GP18	GP19
   Pro Micro, Leonardo, Micro	2	3
   Uno	A4	A5
   Mega	20	21
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

For d-pads that are integrated with the main board it is advised you skip wiring the dpad as you have to solder directly to the contacts and run wires accross the board. You will either be able to use your keyboard for these buttons, or they really won't really be needed as the games were designed to be controlled with the guitar alone. Below is an example of what this can look like, and why it is advisable to skip.

For guitars with a DPad that is seperate, it will be much easier to wire as you can follow the traces and wire it to the pins like you would for start/select.

1. Find ground. There will be a single common ground and a pin for each direction or multiple "grounds" depending on the model. (some may once again be labeled as col or column) Just like for start and select, you will need to follow the traces to figure out which pin is GND. Mark GND, then connect it to a GND pin on the microcontroller. If there are more than one ground wires, you can twist them together and combine them again.
2. Up and down on the dpad MUST be connected to the same pins you will be using for strum. You will want to twist those wires together and solder them to the same pin. You may want to wait until you are working on the strum to connect these pins.
3. Home, left, and right can be connected to any unused digital pin on the microcontroller.

For guitars with a joystick, there will be four pins, one is V_CC, one is GND, one is the x axis and one is the y axis. You can work out which is which by tracing the traces, however on some guitars the traces are labelled for you. The joystick needs to go to an analogue pin (one of the A pins)

1. For the frets, if it is not labeled it is easiest to open up the neck and follow the traces between the fret contacts. The ground wire traces will connect to all of the fret contacts, whereas a fret trace will lead to a single fret contact. At the end of this guide, there are some images for known neck pinouts. If using the multimeter, test between the fret wire and the ground wire, and the multimeter should beep when the fret is pressed.
2. Connect the common grounds to a ground pin on the microcontroller.
3. Connect each fret to its own unused digital pin.

The Strum switches are similar to the start and select buttons, they will be three wires on some guitars. For these situations it is easy enough to connect to the microcontroller.

1. Connect Strum
2. Connect the common ground to a GND on the microcontroller.
3. Connect each strum switch to seperate unused pins on the microcontroller.

On others, the Strum switches are a part of the main PCB, and you will need to solder directly to the strum switches, which should poke out the back of the main PCB. For example, on a wiitar, you will see the following:

In this case, there are two grounds that will be shorted together, so with the multimeter, you should be able to work out which pins are ground, by testing a pin from each switch, and working out which ones are shorted together by it beeping.

Note that you can also choose to replace the original PCB with a 3D printed strum switch holder. If you want to go that route, there are some designs around for various guitars. The image at the beginning of this guide shows how this would look.

When the strums are part of the main board you will need to cut the traces or you will have phantom inputs as your signal will still be traveling through the motherboard. (this is when your strum switches constantly input and you likely cannot autobind inputs in the configurator) You will need to take a knife and cut any traces that connect to the strum switches. In the picture below, the person did not cut many traces as they knew which ones were causing phantom inputs. Cutting extra traces is not going to affect your arduino guitar, as none of the traces are used except the one that connects the two grounds of the switches together. Even if you accidentally cut that trace, you will be able to connect the grounds again with a little extra wire.

1. If you are using a USB extension cable, cut it in half and expose the four cables.
2. Hook up the V+ / VBUS (Red) to the VBUS pin on your Pi Pico
3. Hook up the V- / GND (Black) to ground on your Pi Pico
4. Hook up D+ (Green) to one side of a 27ohm resistor and the other side to a unused digital pin.
5. Hook up D- (White) to one side of a 27ohm resistor and the other side to the digital pin directly after D+. For example, you can hook up D+ to GP2 and D- to GP3.
6. Connect a 47pF capacitor between D+ and ground
7. Connect a 47pF capacitor between D- and ground

The world tour slider bar originally used a single wire to connect between the bar and the main PCB. This caused a lot of problems, as the format of data being sent over this wire is not optimal for speed, and it limits the combinations of frets we can read from the slider bar. To combat this, we bypass the chip generating this data, and opt to use a dedicated touch sensor chip, the MPR121, to handle reading from the slider bar and sending us data in a format that we can easily use.

1. Cut the traces indicated with red lines in the following image on your Slider bar PCB. You can also opt to just desolder U2 if you prefer.

   

2. Solder each of the circled vias on the WT Slider bar PCB to its own channel on the MPR121. It is recommended to use channels 0-4 for the slider bar, as the MPR121 requires assigning touch pads first before other pins.

   

3. For the frets, follow the traces between the fret contacts. The ground wire traces will connect to all of the fret contacts, whereas a fret trace will lead to a single fret contact. At the end of this guide, there are some images for known neck pinouts. If using the multimeter, test between the fret wire and the ground wire, and the multimeter should beep when the fret is pressed.

4. Connect the common grounds to a ground pin on the MPR121.

5. Connect each fret to its own unused channel on the MPR121.

6. Hook up V_CC (marked as 3.3V) and GND (marked as GND) to the microcontroller. Note that this means you need to use a 3.3V power pin on your microconroller, so if your microcontroller only has 5V power pins you will need a voltage regulator.

7. Hook up SDA and SCL to the microcontroller

   Microcontroller	SDA (D)	SCL (C)
   Pi Pico (Recommended)	GP18	GP19
   Pro Micro, Leonardo, Micro	2	3
   Uno	A4	A5
   Mega	20	21
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

1. Hook up V_CC (marked as V or V_CC) and GND (marked as GND or G) to the microcontroller

2. Hook up SDA (Marked as D) and SCL (marked as C) to the microcontroller

   Microcontroller	SDA (D)	SCL (C)
   Pi Pico (Recommended)	GP18	GP19
   Pro Micro, Leonardo, Micro	2	3
   Uno	A4	A5
   Mega	20	21
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

1. Hook up V_CC, GND, SCL and SDA pins to your microcontroller. Note that this is one of the few I2C devices that works perfectly fine on 5v.

2. Hook up SDA (Marked as D) and SCL (marked as C) to the microcontroller

   Microcontroller	SDA (D)	SCL (C)
   Pi Pico (Recommended)	GP18	GP19
   Pro Micro, Leonardo, Micro	2	3
   Uno	A4	A5
   Mega	20	21
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

1. If you wish to bypass the neck connector for your frets, there are three choices, you can opt to wire the frets directly from the fret pcb to the pico, you can use an MPR121 and avoid needing to run more wires, or you can use peripheral mode and avoid needing to run more wires. The MPR121 replaces the entire slider bar PCB and handles both the slider pads and the frets, while the peripheral only handles the frets, and requires using the original slider bar PCB for keeping slider functionality.
2. For direct mode, run a wire from the fret pin to a pin on the pico, and make sure there is a wire from the ground pin on the fret pcb to the picos ground pin.

1. In some cases, you may want to poll frets directly, but you still wish to use a neck connector that does not have enough pins to connect the frets. You can get around this by using an MPR121.

2. Cut the traces going from the main chip to the pads on the slider PCB.

3. Solder each via on the Slider bar PCB to its own channel on the MPR121. It is recommended to use channels 0-4 for the slider bar, as the MPR121 requires assigning touch pads first before other pins.

4. For the frets, follow the traces between the fret contacts. The ground wire traces will connect to all of the fret contacts, whereas a fret trace will lead to a single fret contact. At the end of this guide, there are some images for known neck pinouts. If using the multimeter, test between the fret wire and the ground wire, and the multimeter should beep when the fret is pressed.

5. Connect the common grounds to a ground pin on the MPR121.

6. Connect each fret to its own unused channel on the MPR121.

7. Hook up V_CC (marked as 3.3V) and GND (marked as GND) to the microcontroller. Note that this means you need to use a 3.3V power pin on your microconroller, so if your microcontroller only has 5V power pins you will need a voltage regulator.

8. Hook up SDA and SCL to the microcontroller

   Microcontroller	SDA (D)	SCL (C)
   Pi Pico (Recommended)	GP18	GP19
   Pro Micro, Leonardo, Micro	2	3
   Uno	A4	A5
   Mega	20	21
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

1. In some cases, you may want to poll frets directly, but you still wish to use a neck connector that does not have enough pins to connect the frets. You can get around this by putting a second Pi Pico in the neck.

2. Choose some SDA and SCL pins on each Pico, and connect them by these pins.

   Microcontroller	SDA	SCL
   Pi Pico (Recommended)	GP18	GP19
   Pi Pico (Advanced, Channel 0)	GP0, GP4, GP8, GP12, GP16, GP20	GP1, GP5, GP9, GP13, GP17, GP21
   Pi Pico (Advanced, Channel 1)	GP2, GP6, GP10, GP14, GP18, GP26	GP3, GP7, GP11, GP15, GP19, GP27

3. Connect the Slider bar to the same SDA and SCL pins

4. Connect VBUS and GND between the two Pi Picos.

5. Connect the Slider bar to 3.3v and GND on the peripheral Pico.

6. For the frets, if it is not labeled it is easiest to follow the traces between the fret contacts. The ground wire traces will connect to all of the fret contacts, whereas a fret trace will lead to a single fret contact. At the end of this guide, there are some images for known neck pinouts. If using the multimeter, test between the fret wire and the ground wire, and the multimeter should beep when the fret is pressed.

7. Connect the common grounds to a ground pin on the peripheral Pico.

8. Connect each fret to its own unused digital pin on the peripheral Pico.

1. Click on the button you want to configure, and make sure the Input Type is set to Digital Pin Input.
2. Click on the Find Pin button, and then press the button on the guitar. If you have wired everything correctly, the tool should detect the pin and the icon for that button should now light up whenever the button is pressed.

1. Click on the home / Xbox / PS button.
2. Set the Input Type to Shortcut
3. Set the next Input TYpe to Digital Pin Input
4. Click on the first Find Pin button, and then press the start button on the guitar. If you have wired everything correctly, the tool should detect the pin.
5. Click on the second Find Pin button, and then press the select button on the guitar. If you have wired everything correctly, the tool should detect the pin and the icon for the home button should now light up whenever both start and select is pressed.

1. Click on D-pad Left, and set the Input Type to Analog Pin Input.
2. Set Type to Joystick Negative
3. Click on find pin and move the joystick left or right
4. Adjust the threshold so that the D-pad Left icon lights up when you have pushed the Joystick far enough to the left. This means you can adjust how sensitive you want your joystick to be.
5. You can do the same for D-pad right, however, set the Type to Joystick Positive instead.
6. If you wish to also map joystick up and down, click Add Setting and add another Strum Up and Strum Down input. Then you can follow the above instructions again, only using negative for up and positive for down, and when detecting the pin, move the joystick up and down instead.

1. Click on the whammy, and make sure the Input Type is set to Analog Pin Input.
2. Click on the Find Pin button, and then press on the whammy. If you have wired everything correctly, the tool should detect the pin and the Original Value value should change when you push on the whammy.
3. Click on Calibrate.
4. Release the whammy bar and hit Next.
5. Push the whammy all the way in, and hit Next
6. Release the whammy again, and hit Next. If your whammy is noisy, you can push it in a tiny bit, and the zero position will be set to this location, which will make sure that the whammy is always considered released when it is released.

1. Click on the pickup selector, and make sure the Input Type is set to Analog Pin Input.
2. Click on the Find Pin button, and then move the pickup selector. If you have wired everything correctly, the tool should detect the pin and the Original Value value should change when you move the pickup selector.
3. If the Original Value of the pickup selector decreases as you increase the notch position on your guitar, turn on Invert.
4. Set the pickup selector to the second position
5. Drag the slider for Notch 2 Value so that the current notch is Notch 2.
6. Set the pickup selector to the third position and then move the slider for Notch 3 as detailed above.
7. Repeat this for the other notches. After this, the current notch should reflect the status of the pickup selector.

1. Click on Tilt, and make sure the Input Type is set to Digital Pin Input.
2. Click on the Find Pin button, and then tilt your guitar. If you have wired everything correctly, the tool should detect the pin and the tilt icon should light up whenever you tilt the guitar.
3. If you are using a SW520D based tilt sensor, some versions of this sensor will have an inverted output. You can turn on the Invert option to correct this.

1. Click on Tilt, and make sure the Input Type is set to Analog Pin Input.
2. Click on the Find Pin button, and tthen tilt your guitar. If you have wired everything correctly, the tool should detect the pin and the tilt Original Value value should change as you tilt your guitar.
3. Click on Calibrate
4. Tilt your guitar down, and then hit Next
5. Tilt the guitar up, and then hit Next
6. Hold your guitar in its resting position and then hit Next.

1. Click on Tilt, and make sure the Input Type is set to ADXL345 Input.
2. Set the SDA and SCL pins that you have used.
3. Hit save.
4. Click on Calibrate
5. Tilt your guitar down, and then hit Next
6. Tilt the guitar up, and then hit Next
7. Hold your guitar in its resting position and then hit Next.

1. Click on MPR121 Settings
2. Enable the Peripheral
3. Set the SDA and SCL pins that you have used.
4. Set the MPR!21 Capacitive Touch Pad Count based on the number of touch pads you are using. For a normal slider bar, this should be 5, or if you aren't using a slider bar set this to 0.
5. Hit save

1. Click on Peripheral Settings
2. Enable the Peripheral
3. Set the SDA and SCL pins on the main PCB that are being connected to the peripheral.
4. Hit save

1. Click on Add Setting, and add a Slider setting
2. Set the Input Type to MPR121 Input
3. Hit Save Settings. Note that everything else needs to be configured before you can do this.
4. Set the channels based on your wiring. The configuration will update live, so if you are unsure which via maps to which slider pad, you can just work through the channels and assign things to the correct pads by touching each pad and working out which channel is which.
5. Go to each fret, and set its Input Type to MPR121 Input.
6. Set the channel based on your wiring. If you are unsure which channel you used, you can just walk through each channel and work out which one was used, as the status of the MPR121 will update live as you press and release frets.

1. The GH5 neck puts inputs over a single set of pins. This does add a bit of latency to the frets, but if you want the simplest wiring, you can keep the frets connected to the neck.
2. Click on Add Setting, and add a GH5 Neck Inputs setting
3. Set the SDA and SCL pins to the pins you used when you wired up the neck.
4. If you would like to map the slider bar to the standard frets, you can enable "Slider to frets". Note that if you are using Rock Band mode, the tap bar is automatically mapped to the solo frets.
5. Click on enable for each of the frets.

1. The Crazy Guitar neck puts inputs over a single set of pins. This does add a bit of latency to the frets, but if you want the simplest wiring, you can keep the frets connected to the neck.
2. Click on Add Setting, and add a Crazy Guitar Neck Inputs setting
3. Set the SDA and SCL pins to the pins you used when you wired up the neck.
4. If you would like to map the slider bar to the standard frets, you can enable "Slider to frets". Note that if you are using Rock Band mode, the tap bar is automatically mapped to the solo frets.
5. Click on enable for each of the frets.

1. If you wish to have better latency frets with these necks, you can replace the slider bar controller with an MPR121, which will give you low latency but will still use the same amount of wires.
2. Click on Add Setting, and add a `Slider` setting
3. Set the `Input Type` to `MPR121 Input`
4. Hit `Save Settings`. Note that everything else needs to be configured before you can do this.
5. Set the channels based on your wiring. The configuration will update live, so if you are unsure which via maps to which slider pad, you can just work through the channels and assign things to the correct pads by touching each pad and working out which channel is which.
6. Go to each fret, and set its `Input Type` to `MPR121 Input`.
7. Set the channel based on your wiring. If you are unsure which channel you used, you can just walk through each channel and work out which one was used, as the status of the MPR121 will update live as you press and release frets.

1. If you wish to have better latency frets with these necks, but do not want to hardwire the frets, you can instead opt to use the peripheral mode. You can still follow the Standard wiring if you would like the slider bar to work, but then you do not need to enable the frets as we will bypass the original neck for those inputs.
2. Go to each fret, and set its Input Type to Digital Pin Input (Peripheral).
3. Use Find Pin to detect the pin your fret was hooked up to.

1. Click on Add setting
2. Find and add USB Host inputs
3. Bind D+
4. Hit Save
5. If you plug in a supported controller, the tool should detect it and tell you what it is.
6. If you have a modded xbox and are using usbdsecpatch, you can disable Authentication for Xbox 360.