Zaunkoenig M3K PCB

STEP file for the PCB of the Zaunkoenig M3K. This file is not intended to be printed out. It is intended to help you design a gaming mouse shell for the M3K PCB.

A few notes about the screws used for the M3K PCB (identical to the M2K PCB):

• We use two T6 M2 screws at the front left and right; those are used for the height adjustment functionality of the M3K PCB (0.159 g each).

• We use three T6 M2 screws to screw the M3K bottom shell into the M3K carbon fiber shell (0.196 g each). 

• We use two T4 M2 screws to screw the M3K PCB onto the M3K bottom shell (0.106 g each).

• See this M2K disassembly video by BeardedBob for more information (this video is applicable for the M3K as well).

A note about the distance between the sensor and your tracking surface (your mouse pad):

PixArt in the 3360 data sheet (and in the 3399 data sheet as well, but that data sheet is not public) recommends a «Distance from Lens Reference Plane to Tracking Surface» of at least 2.2 mm, 2.6 mm at most with the typical value being 2.4 mm.

Weight overview:

• M3K PCB (including lens): 6.7 g

• M3K wheel: 0.9 g

• All seven screws: 1.118 g

A few notes about the cable setup we use for the M3K PCB (identical to the M1K/M2K PCB):

• Pinout: The black conductor (ground) should be inserted into the Molex receptacle so that it is the one closest to the sensor, followed by yellow (D+), white (D-) and red (5 Volt).

• The M3K cable has a diameter of 2.0 mm ±0.1 mm.

• Crimps: The little golden thingies that are on the end of each of the four conductors are called crimps. The ones on the M3K cable are made by Molex and are from their Pico-Lock product family (MPN: 5040520298).

• Crimp receptacle: The black plastic part that you insert the four crimped wires into (MPN: 5040510401).

• PCB header: This is the part that you insert the crimp receptacle into. This part is soldered onto the M3K PCB, so normally you do not need buy it for a mod with the M3K PCB (MPN: 5040500491).

• Crimping tool: The official crimping tool for the above crimps costs $540, which is pretty expensive (MPN: 0638270900). If you only want to crimp one cable it is not worth it spending that much. Instead just get the Engineer PA-09 or the PA-11 (see this article for a comparison of both).

• If you want to use a different cable see this guide by kyleirelandtech on how to install an Enncoo AirCord in an M2K; this guide is applicable to the M3K as well.

A few notes about the modding capabilities of the M3K PCB:

You can modify the M3K PCB either by modifying the open-source firmware of the M3K or by using the various castellated holes on the M3K PCB (castellated holes are the round and golden indentations on the sides of the M3K PCB).

Note that the M2K PCB actually consists of two separate PCBs. The wheel encoder and middle mouse button switch sit on a separate PCB that can be connected to the main PCB with a so-called Board-to-Board connector (Molex SlimStack).

There are various castellated holes on the M3K. All important signals are broken out (NRESET, NCS, MISO and MOSI are for the SPI communication between the sensor and the MCU, for example). We have also broken out MCU pins that are currently unused. PA4 and PA5 for example could be used to connect an additional switch to the M3K PCB (this would require modification of the firmware as well though).

Here is a screenshot of the pinout of the castellated holes in the bottom of the M3K PCB:

The following screenshot shows the pinout for the castellated holes in the middle of the M3K PCB:

See the following screenshot for the pinout of the castellated holes for the wheel PCB: