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0xC.pad & 0x33.board

Two exciting projects from s-ol, both with HEX keycaps: the 0xC.pad and 0x33 MIDI controller.
Published July 7, 2022
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I've been following s-ol's WIP 0x33.board project for some months, waiting for the right time for a write-up, just to miss the r/mk announcement he posted a few days ago… :D

So in the photo above, you can see a low-profile (Kailh Choc) macropad (0xC.pad) and the bigger 0x33.board which is still a prototype. From the keycaps to the PCBs, case, and firmware (for the MIDI keyboard) everything was designed by Sol Bekic aka s-ol.

The thing that stuck me first of all, obviously, is the hexa keycap and grid – with the promise of a whole new ecosystem of projects and accessories.

I prototyped the hexagonal keycaps with various milling and casting techniques before partnering with fk-caps to make injection molded parts – s-ol.

So these will be available soon. Product page on But more on the HEX keycaps in a separate post.


The 0xC.pad has a two-part case machined out of aluminum.

Pic: 0xC.pad designed by s-ol

0xC.pad designed by s-ol

By the way, 0xC is the hexa representation of 12 so the name is probably a reference to the 12 keys of the macropad.

The designer iterated using laser-cut wood at first, before machining his own aluminum parts ("quickly realizing it's not his forté") and finally working together with a professional CNC shop to make quality anodized parts. Everything else is ready, the 0xC.pad kits will become available as soon as the first keycaps arrive. UPDATE: Product page on

Btw, s-ol meticulously documents his progress so you should check out his posts on Mastodon and also resources on his fabcloud page and blog – like this page on the 0xC.pad.

I also reached out to Simon from FKcaps who teamed up with s-ol and thinks this project is literally the definition of "think outside the box" when it comes to keycaps and that's what looked so appealing to him.

S-ol was working on this project and posted about it somewhere online (probably Reddit) and when I saw it I was just too excited and reached out. […] When it came to funding the project, we originally aimed to make a GB for a small macropad after running an IC at the end of 2020. But because we strongly believe in the project at FK, we eventually decided to purchase the keycap molds as well as a few hundred units of the macropad, in order to avoid the pitfalls of the GB funding model – Simon.


The bigger 0x33.board is still a prototype. It's a 48(+3)-key "isomorphic MIDI controller" – the 0xC → 12 introductory exercise helped a lot, otherwise I may have missed that 0x33 is 51 in decimal. :D

I'm experimenting with different materials for the 3-part case – s-ol.

This current setup uses a 4mm MDF plate on the bottom, and a top plate and cover made from acrylic. An earlier prototype was all wood and also came out really nice, so s-ol is thinking about making these with different combinations.

Pic: I love how even the cable is connected in an angle.

I love how even the cable is connected in an angle.

So this is a MIDI keyboard. I've featured various musical instruments on, and especially those using the Wicki-Hayden layout – like the Gatgetina and Melodicade – could benefit from hex-shaped caps. But now here is the 0x33.board.

In addition, the firmware is based on CircuitPython and can be reprogrammed and customized while the keyboard is attached to the computer. As usual with CircuitPython or KMK boards introduced recently, the 0x33.board shows up as a flash drive in addition to the MIDI device. When you edit the Python source code on the drive, the keyboard reloads automatically.

Unlike the 0xC.pad, I'm considering to make these niche musical keyboards on-demand with electronics assembled and cases lasercut all by myself locally – s-ol.


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Published on Thu 7th Jul 2022. Featured in KBD #86 (source).


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