MX MIDI Guitar

Strum Hardware Screws

Gather the following hardware for creating the strum mechanism.

Hardware

4x M3 x 10mm pan head screws
4x M3 hex nuts

Install Hinges

Insert a screw through the bottom of the pick-mount.stl part. Place one of the pick-hinge.stl parts on top of the standoffs. Insert and fasten an M3 hex nut onto the thread of the screw.

Secure Hex Nuts

Repeat the process for all four standoffs. A pair of needle nose pilers can assist in grasping the hex nuts for a secure fitting.

Install Joints to Pick

Install the two pick-joint.stl parts into the pick-base.stl by inserting them from the inside. The flange should be flush with the inner wall of the pick-base.stl.

Hot Glue Joints to Pick

Apply a moderate amount of hot glue to the inside of the pick-base.stl. This will prevent the pick-joint.stl from being pushed in and secured in place.

Strum Pick with Joints

Double check the joints are installed on both ends.

Install Pick to Base

Begin to install the pick-base.stl part into the pick-mount.stl. Fit one of the ends into one of the pick-hinge.stl parts. Flex the pick-mount.stl slightly to allow the second pick-joint.stl part to fit into the second pick-hinge.stl.

Installed Pick

Double check both ends are installed properly. The pick-base.stl should rotate freely.

Pick Assembly

The pick assembly is ready for the next set of parts.

Parts for Micro Switches

The two micro switches need 4x M3 x 16mm long machine screws and 4x M3 hex nuts. The switches will be mounted to the pick-plate-sw-left.stl and pick-plate-sw-left.stl parts.

Secure Switches to Plate

Place one of the micro switch onto either of the pick-plate-sw parts. Orient the micro switch so the mounting holes are lined up with the plate. Insert one of M3 x 16mm long screws through the micro switch and plate. Insert and fasten an M3 hex nut to secure the switch to the plate.

Installed Switches

Repeat this process for the second micro switch. Double check the orientation of the switches are matching with the photo.

Wires for Micro Switches

Use the following wires for connecting the micro switches.

2-pin JST female cable – 114mm long
4-wire ribbon cable – 180mm long
2x 2-pin JST male connectors

Tinning Wires

Separate the 4-wire ribbon cable so there's 2x 2-wire cables. Use wire strippers to remove a bit of insulation from the tips of each wire. Tin the ends using a bit of solder – This will prevent the strands of wires from fraying. Third helping hands can help assist while soldering.

Wire JST Connectors

Solder up the 2-wire ribbon cables to the male 2-pin JST connectors. Don't forget to add heat shrink tubing before soldering – This will insulate the exposed wires and prevents connections from shorting out.

2x 2-pin JST Cables

Repeat this process for the second 2-pin ribbon cable.

Micro Switch Ground Wire

Solder one of the wires from either 2-wire ribbon cable to the common ground on one of the micro switches. The ground is labeled on the side of the micro switch "COM". Tinning the pin of the micro switch can help solder adhere to the wire.

Solder Micro Switch Pin

Attach the other wire to the "NO" (Normally Open) pin on the micro switch.

Wired Micro Switches

Repeat this process for the second micro switch. Double check the wires are connecting to the correct pins and have solid connections.

Strum Installation

Get the parts for the strum assembly. The mounting plate, micro switches and pick base. This will need 4x M3 x 6mm long screws and 4x M3 hex nuts.

Install Strum Mounting Plate

Insert 4x M3 x 6mm long screws through the back of the guitar body. Use the four mounting holes in the center near the middle of the body. While holding screws in, place the pick-mount.stl part over the screws so the threads go through the four mounting holes.

Install Micro Switches

Place the two (pick-plate-sw-left.stl and pick-plate-sw-right.stl) micro switches over the threads of the screws. Reference for the photo for correct placement.

Secure Strum Parts

Insert 4x M3 hex nuts onto the screws and fasten tightly to secure the strum assembly to the body of the guitar.

Install Pick to Hinges

Fit the joints on the end of the pick-base.stl to the hinges on the pick-mount.stl. Start by fitting one end and then the other end. The parts can flex slightly to offer more clearance for the joints to be fitted into the hinges.