KeyMouse Alpha 300 Series Assembly Instructions

(Updated 06/02/2022)



Parts to 3D Print per Hand

To access the STL files to 3D print the parts needed, fill out the KeyMouse Maker Program Agreement, and email it to This email address is being protected from spambots. You need JavaScript enabled to view it. and we will get back to you with the requested STL files.

Note: Make sure to double quantities if assembling both hands

1 x Top Housing
1 x Bottom Housing
1 x Side Button Holder
  5 x Adjustable Feet (various heights available for leveling device)


If 3D printing your own housings, please refer to the notes below:
A build volume of at least 225mm x 225mm is required (refer to spec sheet for dimensions of KeyMosue Alpha) 

  1. Small
  2. Medium
  3. Large
  4. XLarge

To print using ABS filament (recommended), 3D printer must be enclosed to retain heat. A heated bed is also necessary for ABS.
For best print quality, print with 0.4mm nozzle and 0.15mm layer height.
The amount of 1.75mm filament used in grams for each part is:
Top Housing - 156g
Bottom Housing - 100g
Side Button Holder - 13g
Adjustable Feet - 5g (approx. for 5 feet)


Parts to Purchase per Hand

Note: Make sure to double quantities if assembling both hands

1 x  Main PCB Module 3.0
  5 x Cherry Key Modules with punch-down (5 pack)  
  1 x Complete Key Cap Set
6 x Blue Small Button Modules (for F Keys)
3 x Black Small Button Modules (for Mouse Clicks)
  1 x Small Button Cap Set
  1 x Red Wire for punch-downs (10 pack) (Note, you will only need to purchase this once per set)
1 x Blue Wire for punch-downs (10 pack)
1 x Backlight Wire for punch-downs (2 pack)
1 x Ceramic Feet 

5 x 2.3x10mm screws for screwing top & bottom housing together

16 x 2.3x6mm screws for components

4 x 2.3x4mm screws for Main PCB 3.0

or Screw Pack for KeyMouse Alpha - One Hand



General Notes Before Starting

1. Do not plug in the Main PCB Module to the computer until all components are in place and securely fastened. The Main PCB will be damaged if short-circuited.
2. The example images are using Right Hand KeyMouse Alpha. Apply the same steps for the left hand (with a few exceptions...we will show instructions if the left hand is different).
3. When installing screws, you will need to gently tighten them so they don’t strip the 3D-printed plastic.
4. There are tight tolerances, so keep all wires and everything as tidy as possible to ensure housings can close properly when assembly is done.
5. Tools needed: small Phillips screwdriver and a 28 gauge wire punch-down tool

How to Assemble Your KeyMouse

1. 3D Printed KeyMouse Alpha parts for Assembly



2. Main PCB - Starting with the Bottom Housing, place the Main PCB inside, aligning holes with mounting bosses. Screw in using 4mm screws.




3. F Keys - Snap the F7-F12 (F1-F6 on Left Hand) button caps onto six of the blue Small Button Modules, so the lettering “S1” is at the bottom, as shown in the picture. Then, face the Top Housing upside down and insert the six Small Button Modules (make sure the “Col” lettering is on the top on all six), then secure using 6mm screws.




4. Snap Cherry Key Modules in Top Housing - using your thumb, press each Cherry Key Module into the top housing. Make sure the LED is on the top side (toward the back of the device). When pressing them in, they should make a “snap” sound when they are all the way in.




5. Side Button Holder (Mouse Buttons & Scroll Wheel) - Snap the mouse buttons onto the 3 black 5 Million Lifecycle Small Button Modules so that the lettering “S1” on the PCB is on the bottom, as shown in the picture. Place the Small Button Modules into the Side Button Holder and secure with 6mm screws. Mount the Scroll Wheel to the Scroll Module, by pressing the end of the Scroll Wheel into the black part of the Scroll Module. Then Align the Scroll Module holes with the Side Button Holder holes and secure with 6mm screws.





6. Punch down wires - Important: Hold in the Cherry Keys from the opposite side as you are punching the wire down. If you fail to hold down the Cherry Keys, they WILL pop out and rip the wire. You also have to hold the side button holder in place as you are punching the wire down. You can do this with either your hand or with our 3d printed jigs. You MUST connect “Rows” to the Row pins, and “Columns” to the Column pins on the Main PCB 3.0, or the keys will not work. Each key has a diode to prevent “ghosting”. Using the punch-down tool, punch wires closest to Main PCB outwards leaving a little bit of slack between each key. 


7. Rows Complete



9. Columns Complete




10. Rows & Columns Wiring Complete



11.  Backlight (-) complete - 1 yellow wire



12. Backlight (+) complete - 1 green wire


13. Connect Scroll Wheel Cable & screw in Side Button Holder - Connect the 3-pin cable from the scroll module to the Main PCB (with the black wire on the far right pin of the scroll module when looking at a topdown view of the pins) and then Screw Side Button Holder into place using 6mm screws. IMPORTANT (For the scroll wheel to scroll correctly) Make sure the black wire is in the ZA pin on the Main PCB for the KeyMouse Right hand. Make sure the red wire is in the ZA pin on the Main PCB for the KeyMouse Left hand.


14. Double Check Connections - Make sure all connections on Main PCB are tight.

15. Test Devices / Program which is Left Hand / Right Hand - Before screwing the housing together, you may want to test all of the keys to make sure they work. You can download the software at Once the software is downloaded and installed, you will also need to assign what type of devices they are. To do that, open the software, and under the “Devices” tab, click “Firmware Update”. There should not be any devices listed. Connect one device to your computer (not both, just one). Then click the “Advanced” tab and on the top right, you can see from the dropdown what device type and which hand you can assign to it. Select the appropriate options, check the box by the device in the list of devices (should only be the one) then click “Save to Device”. Do the same on the other hand. Then assign your key layouts to the devices and test.



16. Screw Top & Bottom Housing Together - After making sure all wire connections are secure, very carefully make sure all the wires are inside the housings where they won’t get pinched between the housings or between the screw mounting bosses. Try to keep the wires as tidy as possible. Close the top and bottom housings together and secure from the bottom side using 10mm screws.


17. Adjustable Feet - Align the adjustable feet in the designated holes on the bottom housing and press them in with your thumb (you may have to try different sizes to make sure the device sits flat and does not rock on the desk). Once the device is level and you have the desired sizes in, secure with 6mm screws.



18. Ceramic Feet - Place ceramic feet centered on each of the adjustable feet.


19. Key Caps - Flip the device over, and put key caps on the Cherry switches. Make sure to press them firmly with your thumb.




20. Left Hand - Repeat steps 1-19 for the Left Hand.



All Done! Enjoy Your KeyMouse Set!