The DevTerm keyboard is far too small for grownups to type on

EDIT: Having listened to people who have used mini-keyboards with very similar geometry to the DevTerm (on old school pocket computers), it’s apparent that this issue is far more subjective than I first thought. While many people would prefer the solution I propose below, there are also people (grownups) who are already able to proficiently type on similar keyboards to the DevTerm keyboard, and some who prefer the current design.

The DevTerm has tiny keys, with a pitch of roughly 11mm. This is 7mm less than a regular keyboard (and area shrinks exponentially, so 7mm makes a big difference). Grownup fingers when held side by side are roughly 15mm to 20mm apart (tip to tip), so it will be physically impossible for an adult to type on the DevTerm.

Who is it for? The keys are for small children, but it’s marketed to grown men, who would need an external keyboard to use it.


If you need to make a small keyboard, you reduce the number (not the size) of the keys. You need at least four rows of at least ten columns to be at all productive. That works out to 180mm x 72mm.

The DevTerm keyboard is 190mm x 78mm (and keyboard bevels can be any size), so it would be possible to have a very minimal, but grownup keyboard on the DevTerm. There are a bunch of ways you could lay it out, but this example offers a rough idea of the kind of compromises involved:


When electronics manufacturers moved from polystyrene to cardboard, they called in origami masters. The DevTerm designers should have turned to keyboard enthusiasts, who have been making tiny keyboards for ages.

The patent on Cherry MX switches expired some years ago, so you can legally purchase much more affordable copies from Chinese companies (and DevTerm only needs roughly 40 keys, about a third of what’s needed for a standard keyboard).

To address the fact that the copies are less reliable than Cherry’s own switches, they now make switches that can be swapped by the user. The switches just pop into holes in the PCB, which is ideal for a kit-based project like DevTerm.

Using standard switches would make DevTerm compatible with any Cherry MX keycaps.

Quality keycaps with complex, color-coded legends would normally be dye-sublimated, so there is no need to create molds for each key. Using stock blanks with sublimated legends would also make it affordable to produce keycaps for other languages and custom layouts et cetera.

While I’ve kept an eye on the DevTerm, this was the main reason I didn’t pre-order. While the hardware is impressive, to me, it’s too close to a more attractive version of the Pocket C.H.I.P. which was the last device Next Thing Co. made. I bought one of those, and it’s still a nifty piece of history, but it was most useful for the device inside. Obviously the DevTerm hardware is modern and much better, but if it’s not usable without at least a keyboard, and perhaps a keyboard and a screen…

My guess is the screen and keyboard on the DevTerm will be fine for small edits to files, or perhaps quick network diagnostic commands and the like. If custom applications are built for it, that limit the amount of data entry required to do things, then it could be used for all sorts of stuff. But I seriously doubt anyone is going to write their novel on it. Or do actual coding on it, beyond maybe a quick bug fix or small tweak.

I’d love to be proven wrong, but I made the personal decision to wait, and hold out hope that there will be further work done and releases for the GameShell. I also hope the DevTerm finds a purpose, and is a success. It’s incredibly cool as a piece of nostalgia and I could see it being something of a hacker tool if it gets enough development interest and enough applications become available for it, but I can’t really see it being that comfortable as a portable Linux machine.

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Guessing you hold like a blackberry and type with thumbs or place on desk and peck with index fingers? Specs says its a 65% keyboard, so shouldn’t be too bad?

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Hi Jase.

Clockwork are completely incorrect to describe it that way. What they have is nothing like a 65% keyboard.

The 40%, 60%, 65% (et cetera) keyboards all use the same, standard 18mm pitch, and all use interchangeable keycaps. The percentage only refers (loosely) to a certain subset of a full (100%) keyboard’s keys, where 65% means it includes the keys of the Main Block (like a 60%) with dedicated Arrow Keys (the extra 5%). It has nothing to do with the scale or pitch of the keys.

Hi adcockm,

I think you’re right: You could peck out a search term or a simple one-liner, but the idea that you could learn to code, or develop games or do anything substantial, directly on the device, is for the birds.

The thing is, I’ve seen people asking for blank keycap sets, as they think they will be able to touch type on them. I’ve seen people talking about using DevTerm “in the field”, and they were explicit that they really meant in the field. A large chunk of the buyers think they are going to develop software on their DevTerm, and are going to be pretty disappointed.

In reality, the DevTerm has no usecase.

For comparison, this image contains the smallest 65% keyboard you can buy (Filco’s ANSI MINILA) and the DevTerm keyboard, to scale:

Here’s a more direct comparison:


This is why I recommended a 40% layout. It’s the smallest layout that anyone uses for anything serious, and still only just fits (with about five millimeters spare around the sides).

You can get away with slightly smaller keys (as many laptops have done), but the keys can only be very slightly smaller, and then you cannot use standard keycaps.

Putting a legit 40% mechanical keyboard on the DevTerm would make people want to code on it. As it stands, the keyboard will completely discourage anyone that has to use the DevTerm for coding.

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@carlsmith your rationale seems very very concrete, I hope clockwork team to read your comments and elaborate further on this. A truly usuable keyboard is a must have for DevTerm.

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I can also make pictures of things that looks bigger or smaller. Could you explain how you got your dimensions?

Nobody expect the DevTerm to have a full fledge keyboard, but your comparison seems biased. I doubt it is that small.

Could you explain a bit more your rationale?

Thanks for the explanation here Dimensions of DevTerm? - #4 by carlsmith

As said, I don’t remember the dimension to be there when they first revealed the infos.

Just as the DevTerm offers a range of swappable compute modules, I’d love to see a drop-in alternative keyboard with a smaller number of larger, mechanical keys. If ClockworkPi doesn’t offer one as an accessory, I’d pay a fair price for such a kit as an aftermarket add-on.

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I’d go as far as to say that DevTerm literally has no usecase without an alternative keyboard that, at a minimum, provides full-sized keys. Once you accept the need for a proper keyboard, using Cherry MX compatibles adds so much extra value that it’d just be silly not to.

Ah OK thanks Carlsmith! I’m still not too worried, I spend years on a Blackberry and Treo :smile: But I think as long as this pic is accurate - it should be finger pecking OK? - Capture — ImgBB

I’m in my mid 30’s and my finger tips are actually less than 1.5cm apart. I could possibly be less than average? Could be an Asian thing.

I’ve mentioned this in the past, but the devterm seems to be on par with previous devices I’ve used in the past, size wise. Eg, the Cassiopeia.


I was able to touch type on this device without any major hindrances. Of course a full sized keyboard would be better in the long run.

If not for coding, or similar productivity, I’m sure that the keyboard would lend itself well to people wanting it as a gaming device. The fact it has a Dpad and input keys would imply there is a focus on the play side of things.

I’ve never kept up with keyboard sizes or the nomenclature re: sizes. Is the 60% size clockwork refer to pertaining to key size; while the quotes 60% size of the larger keyboard posted above is compared against a keyboard with a numberpad, bevels and function keys.


It’s fair to assume the DevTerm would be roughly on par with devices like the Cassiopeia. I don’t think that’s unrealistic.

In the past, the experience with mini-keyboards varied a lot from keyboard to keyboard, and person to person, and there were other issues (some devices work well with one language, but poorly with others et cetera). I couldn’t see myself typing very effectively on the Cassiopeia either, but if you actually used one, and became proficient enough to enjoy doing stuff on it, then I won’t argue with that.

Even if the problems with the DevTerm keyboard are going to be less of an issue for some users, I still see many people that are clearly expecting an experience they are not going to be able to have.

If there was a choice of the current keyboard, or one with 40 full-sized (Cherry MX compatible) keys, even if the full-sized keyboard cost 30-40 dollars more, almost nobody would opt for the current design, especially if the keycaps were pretty, and you could customize the layout in interesting ways.

On nomenclature, I think 80% means everything except the Numpad Block. 60% means just the Main Block. 40% means the bottom four rows of the Main Block. And you then add 5%, if the keyboard has dedicated Arrow Keys (and wouldn’t have otherwise), producing 45% and 65%. It’s something close to that anyway.

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We (the community) could design a much better layout than the one I posted before, which I only made to illustrate the kind of compromises we’re discussing. There are plenty of things you could do to improve it, especially if the community got involved in the process.

Mechanical keyboards are relatively simple products to develop and manufacture (when you’re using off-the-shelve switches and keycaps). It’s basically a PCB in a case, so I’m confident Clockwork could design a really nice one.

I’ve been reading the forum posts on the DevTerm with a lot of interest since it was announced.

I have some similarly sized devices that I’ve used in the past, so I thought I’d add some images and thoughts to this thread.

I’m a big fan of the Psion range of pocket computers and used a Psion 3 and 5 until pretty recently.
I even resurrected my Psion 3c recently so I could write things while out for walks in the countryside.

Both have comparable keyboards, the Psion5 having larger more traditional looking keys, the Psion3 has more spaced out calculator style keys. Neither are ideal for traditional touch typing, but I find both work well almost touch typing with one hand while holding the device in the palm of the other, I see this as probably one of the ways you’d use a DevTerm.

On a desk the Psion5 is better, you can comfortably type with two or three fingers from each hand, the Psion3 isn’t as good on a surface, but is better if you want to hold it gameboy style, typing with both thumbs.

As finger tip spacing seems to be a thing in this thread, for the record my fingertips are 19mm apart and I never had a problem getting used to the Psion keyboards.

I think the ‘palmtop’ approach to typing would probably be the most practical with the DevTerm, I have a feeling thumb-typing might not be an option because of how wide the keyboard is.
I think this is also evident with the placement of the mouse buttons and trackball.

I do have some concerns about the usability of the keyboard, it comes down to the quality of the buttons themselves, if the GameShell is anything to go by I think it should be OK, the GameShell buttons have a more positive action than the Psion 3 keys.

As the pitch is almost identical to the Psion 3, So I think it comes down to the physical shape and feel of the keys.

From the renders it looks like the keys are a single rubber molding similar to the GameShells top row of buttons, does anyone know for sure? I think this should be ok as long as the keys top surfaces are concave not convex in shape.

At the risk of people destroying perfectly working Psion 5’s (there should be enough out there with smashed or faulty touchscreens) you can get a USB conversion board for the keyboard, I got hold of one years ago when the PiZero came out with an idea of making a Psion style device, but never found an easily availible screen that suited my plan.

It would probably be easy enough to fit a Psion 5 keyboard into a frame to fit the DevTerm, sacrificing the game buttons, but possibly with enough space at one side for a small trackball and buttons.
This would probably be more practical than using cherryMX style switches as even with low profile keycaps they’re pretty tall.

I have pre-ordered a DevTerm, and I’m really looking forward to experimenting and using it.


@Jon - It’s a very interesting post, and you’re the second person to make a counter-case based on actual past experiences with mini-keyboards. To be honest, I’ve very little experience using them, just because I found them horrible to use whenever I did try, but there clearly are plenty of people that are happy with that approach on a device like the DevTerm.

You’re the first person that seems to prefer smaller keys to less keys, which is interesting. We only have a handful of people contributing to the conversation, so it’s hard to extrapolate anything, but there’s bound to be a substantial chunk of the community that agree with you, so I was clearly wrong to assume everyone would prefer 40 MX keys to the current approach.

For me personally, the MX keys would make the DevTerm a dream device, so I’d be willing to pay quite a lot more money for it (within reason), but with the mini-keyboard, I just don’t think I could enjoy developing software on it. There are clearly people that will really enjoy owning a DevTerm, and that’s cool. I don’t want to push back on that at all.

There’s still scope for a conversation about adding an MX keyboard option, just for those of us that want one, but my initial concern (as expressed in the title of this thread), that almost nobody will be able to use the DevTerm the way they are expecting to, was clearly overstating the problem, which is much more subjective than I thought.

In short, I was wrong. An MX keyboard would be popular, but the current design is a viable approach that many people will be happy with, and some will prefer.

EDIT: I’ve edited the original post so people will immediately see that the issue is much less absolute than I originally stated. I don’t want to put anyone off that would enjoy owning a DevTerm.

@carlsmith I’m glad the issue has been opened up to be a little more nuanced than you first supposed. I do somewhat agree with your point though, in that I think the visual similarity to the likes of a TRS-80 model 100 has led people to mistakenly believe the DevTerm has a full size keyboard. Which will disappoint some people who are expecting a great touch typing experience.
So I think this is an important topic for people to read to get an idea of what they’re looking at.

I would say I’m a big fan of MX switches and use a mechanical keyboard with my desktop computer, If the DevTerm was the same size as a Model 100 and similar slab computers I’d be all for a cherry MX option, but given it’s tiny size I’d prefer more, slightly smaller, keys over fewer, full size, keys.

Given the DevTerm looks to be about 20mm thick at the keyboard, and the processor board, main board and cooling are all below the keyboard, I don’t think standard MX swiches would physically fit without the keycaps ‘floating’ a good centimetre or so above the casing, If you had it laying flat the top row would probably block your view of a portion of the screen.

I think Cherry and their competitors make low profile switches though, which would probably be worth looking into, a compact 4 row keyboard combined with an IBM trackpoint, with those could be really nice.

Ultimately it’ll be hard to know how usable the keyboard will be until people have the finished product in hand though.

After stating that using MX mechanical keys would block the screen I did quick 3D sketch to double check. You loose the lower eighth or so of the screen if you had it layingflat on a desk . . although those are standard profile keycaps I drew, so It might not be quite so bad in reality.

Either way The DevTerm would look pretty cartoonish with full size, full travel mechanical keys.