MASPLIT: 3D printed keyboard
28 Feb. 2020 / Edit ✏️
*MASPLIT* (means *magnet* and *split*) is a handmade, 3D printed, ergonomic, ortholinear, split, programmable keyboard.
After I made the [3D printed *NOVEM* keypad](/novem) I decided to build a larger keyboard.
I got the idea of making a split keyboard. Since the two parts of the keyboard are separated, you can place them as
you like to they fit your wrist orientation better than non-split keyboards. I decided to build such a keyboard hoping
that it would take my wrist pain away. Also, *MASPLIT* has magnets 😉
![MASPLIT][masplit-top]
The MASPLIT keyboard.
## Parts used All the parts used to make the *MASPLIT* keyboard: - 60 **Gateron Silent Brown switches**; - 60 **keycaps**; - 50 **1N4148 diodes**; - 2 **3D printed cases**; - 2 **3D printed top plates & 2 3D printed bottom plates**; - 2 **ATmega32U4 microprocessor**; - 4 **3D printed connectors holders**\*; - 2 **micro USB male connectors**; - 2 **micro USB female connectors**; - 2 **3-pole 3.5 mm TRRS female connectors**; - 2 **3-pole 3.5 mm TRRS male connectors**; - 1 **paracord sleeve**\*\*; - 10 **1\*5 mm circular magnets**; - 24 **M2 screws**; - 24 **M2 nuts**. **\*** Connector holders are 3D printed parts which hold in place the keyboard connectors such as 2 micro USB female and 2 3-poles 3.5 mm TRRS female connectors. **\*\*** The paracord sleeve is needed to make the sleeve of the handmade 3-pole TRRS cable. ## Design I designed the whole keyboard on the 3D software [Tinkercad](https://www.tinkercad.com). > Find all the 3D files on the [MASPLIT GitHub repository](https://github.com/alexisphilip/masplit). I had a few requirements: - **the keyboard is split in half**; - **has magnets**! (So you can connect two parts together easily.); - **has to be entirely 3D printed, without glue** (so I can change parts easily). Following these requirements, I came up with a modular design. It means I could swap and update any parts I would like, without having to struggle because of glued parts. I had to design a *top plate*, a *bottom plate*, a *case* and two * connector holders*. ### The plates and case It has the same design as the [PUCH keyboard](/puch) that I made, except that it has smaller edges and is split in half 😉. Here are the top and bottom plates for the right side of the keyboard. The left is the same but mirrored. ![Top and bottom plates][3d-top-and-bottom-plates]3D models of the top and bottom right plates.
I then designed the casing, which will fit between the top and bottom plates. It has two parts. One large part has all the screws going through (left), and the other had the magnets in it (right). I made it in two parts, so I could swap the magnets or update that part of the case to a model with USB connectors, or other kind of cool stuff 😉. ![Case][3d-case]3D models of the 2 right case parts, as well as 4 support feet in the middle.
### The connector holders *MASPLIT* needs to be connected to the computer by micro USB and connect the two separated parts by a 3-pole TRRS (jack cable). I designed two modular (without glue) connector holders which fit nicely between the top and bottom plates, the case and the switches. ![Connector holders][3d-connector-holders]3D models of the connector holders.
These two connectors will fit next to each other in the back side of the keyboard. Image bellow is the right side of the keyboard, the 3-pole TRRS connector is on the left, and the micro USB connector is on the right. ![Connector holders in the case][3d-connector-holders-in-case]3D models of the connector holders in the case.
Here's the complete assembled right case with the connector holders in place. ![Case assembled][3d-case-assembled]3D models of the assembled right case.
With all the parts 3D modeled, I began printing them. ## Building Building it was the longest part of the whole project. I'm going to break down the [3D printing](/masplit#3dprinting) and [wiring](/masplit#wiring) processes. ### 3D printing I printed all the parts with a Creality Ender 3. The extruder size is 0.4 mm, and I set the precision to 0.12 mm at 100% infill. The total print time for all the parts was around 17 hours (without taking into account all the prototypes, failed prints, etc). I started to print the *top plates* to see if the switches fit nicely. After, I printed the case and bottom plates. Once they were assembled, I printed the connector holders. ![Printing of the top plate][printing-top-plate]Printing of the top plate.
### Wiring The whole wiring process took me the longest time. **There are 242 soldering points in that build**. The first step of the wiring process was wiring the switches together. It is an easy but long process since there are 170 soldering points in just this step. ![Wiring of the switches][wiring-switches]Wiring of the switches.
The second step if wiring the microcontrollers (ATmega32U4). Since *MASPLIT* is a split keyboard, 2 are needed, one in each part. All the columns and rows are connected to it, as well as the 3-pole TRRS females connectors. These two connectors will allow the two MCUs to *talk* to each other. ![Wiring of the MCUs and 3-pole TRRS female connectors][wiring-mcus]Wiring of the MCUs and 3-pole TRRS female connectors.
After soldering the MCUs and TRRS connectors, it was time to solder the micro USB male/female connectors, which allow them to *talk* to the computer. ![Wiring of the micro USB male/female connectors][wiring-micro-usb]Wiring of the micro USB male/female connectors.
I then attached the 3D printed 3-pole TRRS and micro USB connector holder to the two connectors, and made holes in the 3D printed case to make the connectors accessible from the outside. ![Connector holders in place and soldered][connector-holders-in-soldered]Connectors soldered and with their 3D printed connector holders on the left part of the keyboard. 3-pole TRRS (left) and micro USB (right).
I also built my own TRRS male-to-male cable (jack cable) because why not 😉. I got two 3-pole TRRS male connectors, soldered them together, and then sleeved the cables with the paracord sleeving only. ![Wiring the TRRS male-to-male cable][wiring-trrs]Wiring the TRRS male-to-male cable.
Now that the keyboard is complete, time to flash the microcontrollers! ![Wiring complete][wiring-complete]Wiring complete!
## Programming I used [QMK firmware](https://github.com/qmk/qmk_firmware) to program the microcontroller. I explained a little more what QMK is on my article about [PUCH](/puch#programming). You can find the code I used on the [MASPLIT GitHub repository](https://github.com/alexisphilip/masplit). ## Conclusion ![MASPLIT][double-view]MASPLIT, what a beauty.
After completing *MASPLIT*, it took me just a few minutes to adapt from my [PUCH keyboard](puch). I am glad that all the 3D printed part workout as I desired, and the fact that the two keyboard parts can stick together through magnets is quite nice 😉. **UPDATE 2020-12-07**: I have been using *MASPLIT* daily for about 10 months, and I will keep using it for as long I make a better one. I really enjoy writing on it. The fact that the two hands are split up completely made my wrist pain disappear. The 3D printed part hold up really well even after hundreds of hours of typing and transport. Mission accomplished! [masplit-top]: /static/img/articles/2020-02-28-masplit-top.jpg =100%x* [3d-top-and-bottom-plates]: /static/img/articles/2020-02-28-3d-top-and-bottom-plates.jpg =100%x* [3d-case]: /static/img/articles/2020-02-28-3d-case.jpg =100%x* [3d-connector-holders]: /static/img/articles/2020-02-28-3d-connector-holders.jpg =100%x* [3d-connector-holders-in-case]: /static/img/articles/2020-02-28-3d-connector-holders-in-case.jpg =100%x* [3d-case-assembled]: /static/img/articles/2020-02-28-3d-case-assembled.jpg =100%x* [printing-top-plate]: /static/img/articles/2020-02-28-printing-top-plate.jpg =100%x* [wiring-switches]: /static/img/articles/2020-02-28-wiring-switches.jpg =100%x* [wiring-mcus]: /static/img/articles/2020-02-28-wiring-mcus.jpg =100%x* [wiring-micro-usb]: /static/img/articles/2020-02-28-wiring-micro-usb.jpg =100%x* [connector-holders-in-soldered]: /static/img/articles/2020-02-28-connector-holders-in-soldered.jpg =100%x* [wiring-trrs]: /static/img/articles/2020-02-28-wiring-trrs.jpg =100%x* [wiring-complete]: /static/img/articles/2020-02-28-wiring-complete.jpg =100%x* [double-view]: /static/img/articles/2020-02-28-double-view.jpg =100%x*