Tri-Fold Writer

9/9/25

A continual challenge I have with design work is my tendency to 'start over' with designs and concepts. These 'writer' decks are a great example, my workspace is littered with prototypes and designs in varying degrees of completion.

After tinkering more with the MicroPad design/PCB, I've been forced to admit that I'm not a huge fan of the overall design. The one handed concept definitely has a niche use case. I can definitely see it being useful in many scenarios, but I'm just not super satisfied with it as my own personal device.

I find myself a bit discouraged abandoning/pausing yet another concept. I'd like to get one of these across the finish line AND be personally satisfied with using and making it. Although to be fair to myself, each failed attempt I come away with greater confidence, more refined ideas, and greater knowledge of how to better design the systems involved. Still, its difficult to regain the momentum and motivation to go back to the drawing board. Thus, is the unfortunate plight of tinkerer with ADHD.

Pity party aside, the last several days have been spent re-evaluating the project to better understand what I actually want to pursue. I found my sights firmly fixated on the enigma that is the 'trifold'. A form factor I love and have attempted in the past, but quickly pivoted away from because, admittedly, it was a bit overwhelming. But I feel more equipped to try to tackle it again.

So I've been concept sketching and figuring out the game plan.

Keyboard

One of the biggest challenges of a device like this is the keyboard. Traditional mechanical switches, even 'low profile' ones, result in a device that is just too thick to really be considered 'pocketable'. Alternatives like custom laptop scissor and membrane keyboards are far too complicated and expensive to be practical for a DiY/niche device.

Very few options exist when it comes to user buildable ultra low profile switches. And those that do, have availability issues. The best option currently is likely the Kailh PG1316s. They aren't perfect, Kailh still seems to ironing out issues. They aren't particularly cheap and they are a PITA to solder, but they allow me to achieve a keyboard of the ideal dimension.

Oddly enough, the keyboard is actually one the more simpler parts of this project when it comes to PCB design. And things can be tweaked to work around any changes. So while I have general direction, there will be a lot more research to solidifying the design and parts selection.

Screen/Electrical Comps

In the past I've been relying heavily on the Inkplate hardware and the work of the team at Zerowriter. However because of the overall size constraints I'm diverging on this device. I plan on building the system from 'scratch'. This is the first step I'm working on now: bread boarding and testing functionality. This will allow me to test things like ideal screen size/type, memory utilization, I/O and etc before spending money on an actual PCB.

The end goal is to have a complete PCB 'motherboard' that contains everything including the screen. Once I confirm everything will work how I want it to, I will start the process of PCB development and final parts selection. I've skipped this step in the past, so it'll add a significant amount of development time. The focus right now is primarily rudimentary hardware application. I plan to try to integrate some of the many open source writer firmware GUI, but we'll cross that bridge when I get there.

Current hardware design specs:

ESP32 Based
SD internal / External USB C storage
FSTN (Reflective) display
1000mAH + internal lipo battery

I'm experimenting with a rather small FSTN (New Haven NHD-C12864WO-B1TFH#-M) screen right now. These are great because they offer great visibility in bright light environments, have low power draw, and optional backlighting. I'm certain there will be changes will this, especially after testing. I have doubts regarding resolution and refresh rate, but this is just a starting point; and I happen to have one of these from another project.\

Enclosure

The enclosure here offers one of the more unique challenges, especially considering it with the restrictions of easily accessible manufacturing techniques (aka 3d Printing). It's early stages, but its looking like the design will more closely resemble the Pomera DM5 rather the DM30. The DM30 (and many of the trifold keyboards you can buy online) use a staggered keys to 'interlace' three parts to form a seemingly one piece keyboard. While this is doable, I'm opting to forgo this to simplify the design. Instead my thought is to design the folding halves to feel more a long the lines of a split keyboard.

The hinges also present an interesting challenge. I think I might make post specifically talking about the fundamental challenges these types of devices face when it comes to hinge design and how devices like the DM30 ingeniously solve them. For now I'll just say, eliminating the requirement that the keyboard halves 'slot' together into a single keyboard without a gap greatly reduces the complexity of the hinge design.

Overall, the current goal is a sub 24mm thick device (when folded up). I'll probably never be able to match a true injection device when it comes to slim design, but want it as small as possible while remaining reliable and easy to repair. I have several ideas of how to implement several aspects of the design, but we'll see how this start to come together

Conclusion

It feels good to be working on this concept again, it has always been my unicorn when it came to writer decks. And who knows, maybe this time I will actually get this one over the finish line! I'm gonna try to limit any updates to when I have some actual physical progress and try to avoid things that feel like vaporware hype (concept renders and etc).