OR use the either the naked 18650 mount/naked 21700 mount if you solder wires to the battery directly.
Wireless via Pimoroni Pico Lipo Shim (wireless or direct connection for best of both worlds)
This board is nice because you can direct plug (for lower latency) the pi pico and charge from the same port. The TP4056 version basically limits you to wireless only.
My guitars are using the 3mm switches and they work pretty well, but it looks like the 5mm switches might be better because the mercury seems to flow better in the bigger 5mm switches.
Printer with at least 300 x 300mm build plate.
Printing
Parts should be printed in the orientation provided.
No Supports. Any required supports are already modeled into the STLs.
Buttons/Legs ***Important***
Buttons and legs should be printed at 0.1mm layer height.
Thickness of the leg that inserts into the choc switch should measure 1.25mm - 1.35mm thick after printing for a good fit.
Sometimes slicers do funny things so if your buttons don't fit well you may need to play with the slicer scaling so the legs end up around 1.3mm thick.
If you print the buttons with dimples, they should be printed standing up.
Body, neck, headstock can be printed with 3 walls and low infill.
Feedback/Need Help?
If you have comments, feedback, or need help, please don't hesitate to ask questions or message me. I have printed many of these guitars now, but I do realize everyone's printers/experience are different. So I can help!
Changelog:
2024-06-15
Added tilt switch that supports 5mm mercury switches.
2024-05-25
Added STEP file per request.
2024-03-06
Changed the wire exit hole geometry by removing the upper and lower screw holes. I found that one hole on each side was more than enough to hold the wire plate in place. Thus, the guitar body and all the wire plates are changed.
Guitar Body v1.1
All Wire Plates updated to v1.1
Added plate for the Pimoroni Pico Lipo Shim. Instructions will be updated soon. You will need two m2x4 screws to mount the pico lipo shim.
2024-02-18
Headstock v1.1
Enlarge holes to allow for more adjustability in the neck to headstock interface.
Improve printability of the "groove" in attachment between neck and headstock
Neck with Support v1.1
Improve printability of the "groove" in attachment between neck and headstock
2024-02-16
Added Wire Plate - Micro USB to USB C v1.1
increased thickness slightly. Added recesses so the bolts stick up less.
(3) top of the neck (attach the headstock to the neck)
(9) Faceplate
(16) Guitar Body
(8) to attach the strum bar
(2) for the Pi Pico mount
(2) on the sides for guitar strap mounts
The strap holders mount with m3x12mm bolts.
Note that the rear guitar strap mounting location has two possible locations. There is one at the end of the “arm,” and one under the arm (which is where the actual EVH Star guitar mounts it).
(4) underneath the body to mount the neck.
Fret Switch Plate and Neck Assembly
Neck assembly Video
Break off the supports. The neck in this pic was printed with a color change.
Carefully install fret switch plate with m3 x 8mm button head screws. Tighten until the plate is flush with the neck.
Neck
Place the choc switches into the [fret switch plate]. The switches should be placed so that the keycap mounting slots are perpendicular to the neck.
Solder the wires to the fret switches. The GPIO wires need to be long enough to reach the back corner of the body where the Pi Pico is mounted.
For the ground wires (brown in the pic), I like to solder a short wire to each switch, then merge those wires into one wire at the end of the switch plate after the zip tie holes. You could also do it bus-bar style
Zip tie the wires to the switch plate for strain relief.
Attach the fret switch plate to the neck
Break off the in-built supports on the neck fret-button holes.
Slide the switch plate into the neck and attach it to the neck with (6) m3 x 8mm button head cap screws. Socket head screws will stick up too high and interfere with the fret buttons.
Carefully tighten these bolts until the switch plate is completely flush with the neck. Try to tighten them all a little at a time so the plate comes up evenly.
Buttons
Legs must be printed at 0.1mm layer height. Ideal leg thickness is 1.25-1.35mm
Assemble fret buttons
Glue the legs into the buttons with some super glue. The leg portion goes towards the middle of the button.
Remember the button legs must be printed at 0.1mm layer height for a good fit. The leg thickness should be 1.25 - 1.35 mm after printing.
Install the fret buttons into the switches. If you have issues inserting your fret buttons into the choc switches, it is most likely because the switch plate is not completely flush with the neck.
Attach the neck to the guitar body using (4) m3x40mm bolts.
Strummer Assembly
Strummer assembly
Attach the bearings to the strum bar
Basically any length m3 bolt will fit here. I put m3x12mm in the BOM (to use fewer bolt sizes), but I like to use m3x20.
From outside to in on each side of the strum bar:
Bolt>>mr83 bearing>>strum bar spacer>>strum bar
Insert the bearings into the hole on the [strummer mount]. This should be a pretty snug fit. I have included two versions with different tolerances for the bearing. I personally like the 8.1mm version.
Attach strummer mounts/bar to the guitar body using (4) m3 x 8mm bolts. Center it using the alignment lines on the guitar body.
Switch holders [Switch Holder Choc or Box]
Solder wires and attach switches to the switch holders. There is ziptie for strain relief on the switch holder.
I know the current trend is for box navy switches, but I prefer choc pale blue because the throw is shorter.
Attach the switch holders to the guitar body using (4) m3 x 8mm bolts. I also recommend using m3 washers here, but they aren't required.
Center and adjust the switch locations so there is no play.
Star Button Mount
The Star button can be made dual color with a filament swap.
Attach the body button mount to the guitar body using (2) m3 x 8mm bolts. The opening of the mount should face towards the neck.
Heatsets for the body button are optional.
If your button isn't centered in the face plate hole, you can adjust this slightly with these bolts.
There is a zip tie strain relief on this mount.
Tilt Sensor
Use a zip tie to hold everything in place.
The switch should be mounted with the arms pointing at approximately 3:30 and 5 o'clock. Adjust it to your preferences.
Tilt Sensor
The tilt sensor is designed around two 3mm or 5mm mercury switches. The switches are mounted at an angle to each other.
The right one should point at around 3:30 and the left one at around 5 o'clock with the wires coming out at ~11 o'clock.
This helps mitigate accidental triggers from single axis up and down or side to side movements.
The angle refers to the angle relative to the two switches. a higher angle means fewer accidental triggers, but requires a larger tilt to activate.
Treat the tilt switch as a digital switch. It can be wired to any digital GPIO/Ground.
Wiring
I mount the Pi Pico with the USB port pointing to the back of the guitar.
Wire one wire from each switch to any digital GPIO pin on the Pi Pico. You don't have to worry what GPIO pin you wire the switch to because the Santroller Configurator automatically detects which pin it is later.
Wire the grounds to the Pi Pico. The grounds should be grouped together before connecting to the Pico since there isn't enough ground pins. I group the grounds for the neck switches into one group and group the body switches into another ground group, but do what works best for you :).
If you can crimp duponts I think it is an easy way to get perfect wire lengths.
Otherwise, just solder the wires to the pico and you can tidy them up using the many zip tie holes.
Nice write-up regarding using a TP-4056. I opted to leave out the Schottky diode as I will never be plugging the Pico in after the guitar is wired up. If I do plug in the Pico later to modify the firmware, I will just make sure the switch is turned off.
TP 4056 Charging Module
TP4056 with 18650 Battery
50 ohm resistor for 3mm LED. I wired (-) to pin 33, and (+) to pin 36 on the Pico.
Green light is power light. The hole to the left of the USB-C allows you to see the charging status from the TP4056.
Pimoroni Pico Lipo 18650 Wiring (wireless with 18650)
Wire these 5 pins (colored wires) to the corresponding pins on the pico (Pico pins 40-36)
Put the button into the wire plate then attach the Pimoroni Pico Lipo Shim to the plate with (2) m2 x 4mm screws. The Micro-USB to USB-C extension cable attaches with the provided m3 screws.
Pins 40-36 on the Pico
Wire the two arrow marked spots to ground on the pico (I used Pico pins 3,8).
The battery connector uses a JST-PH two pin plug.
Pimoroni Pico Lipo fully installed with 18650 using the naked 18650 mount. My 18650 was salvaged from a laptop and had tabs on it, so I just soldered wires to the tabs.
NOTE THE ORIENTATION OF THE POWER to the shim. Multiple people have smoked their pico shims by putting the power in backwards.
This is an amazing tool that makes programming a guitar super easy. Check out his excellent documentation also for some other tips on wiring up and configuring the guitar.
In a nutshell, you run the program and plug in your Pico after everything has been wired.
On first plug, it will do a quick installation onto the Pico. Next, hit “configure” and it will pull up all the options.
Choose “guitar” for controller type. Then, on the left there's a button to learn all the keys. Click the ones you have and skip the other ones. Once you've done that, remove any items you don't have a binding for then hit save on the left.
That's it! Your guitar should be working.
Acknowledgements
@joshdesigns for his Les Paul design, which inspired me to make my own version. My strum bar mechanism is inspired by his.
Sanjay900 for creating the Santroller Configurator, which makes programming these guitars a cinch.
Clone hero and YARG creators for allowing me to relive my old guitar hero dreams.