One production calculator and five prototypes


As I'm busily hacking firmware, it occurred to me to take a photo of my desk. The rightmost three calculators were already present, and I added the left three for the photo.

This week has seen a lot of improvements to DIY4X infrastructure code, such as timers and keyboard scanning. While it doesn't add any new features, it does improve the performance, and will make a better base for support of third-party firmware development.


...and what a desktop!!!!!!!!!!!!!!!!!!!!!!!!



If I had the right of choice, I'd take the white one for its keyboard, though its display window looks very ... ummh ... military? retro? outdoor?? If it's possible to have this keyboard together with a LCD allowing softkeys (the keys look so but it's hard to believe) then it would be a no-brainer to decide :-)


The "white one" (DIY3 in 3D-printed case) uses the same 16x2 character display seen in its neighbors to the left and right. The window allows full visibility of the displayable area with some margin.

The -5 is planned to use the same display as the 4X, which is a 2.7" diagonal 400x240 display, well-suited for soft keys.

The intent for the 41-like calculator is to have keys with essentially the same shape, size, and spacing as the HP-41C series (other than the early "tall keys"). The 3D-printed case used an approximation of that.

For a calculator with the Pioneer/20B/30B sort of key layout, would you want keys shaped more like the Pioneer (e.g., 42S), 20b/30b, or 41? We definitely will have constant row spacing, unlike the 20b/30b which have a larger gap between the second and third rows.


For the Pioneer layout, I would prefer the classic Pioneer shape.




With a display as good as this will be and hot/assignable keys, the level of keyboard clutter can be significantly reduced -- does this imply fewer keys are required? I'm not sure.

The 34S has gone overkill with shift and prefix keys, but without a proper menu system and assignable keyboard this is kind of necessary.

- Pauli


I don't think we're likely to build hardware with fewer keys than the Pioneer/20b/30b.


I was more thinking of less than the 41 series.

The bottom five rows are pretty much fixed with digits, arithmetic and the stack manipulations.

Two, three or four rows above is the question?

The 34S has two and lots of shift keys, the 41c has three with one shift.

- Pauli


The 41 only has two more keys than the Pioneer/20b/30b. The big difference is that it is one key narrower, which results in two extra rows (counting the four "special" keys at the top as a row).

I've already said on multiple occasions that we plan to have a model with the Pioneer/20b/30b key layout. That's what we're planning to provide for firmware development. If you want something different than that, let me know.

As currently planned, the width and length will be similar to the Pioneer, but it will have a more pronounced wedge shape due to the battery compartment for two AAA cells at the display end of the calculator.


The key shapes of the 30b would be what I'd go for. Constant spacing is fine for me. I've always regretted HP dropped the slanted keys with the Voyagers - they are simply more space-economical (if that's proper English).


Forgot to mention the number of keys: I vote for 37 as in Pioneers and 20b/30b PLUS a row of six for the softkeys.

My 20m€.


8 rows, 43 total keys? I proposed such a layout here once before, for exactly that reason (softkeys), and it was shot down.

It would result in the calculator being noticeably longer than the Pioneer/20b/30b.


I would prefer the six-column layout, as it makes it easier to manage hexadecimal entry by softkeys (or even by hardkeys, why not?). A 37-key layout, on the 42S style would be nice. I assume DIY5 will have XEQ and ASN (or equivalent) functions, so a not-very-cluttered keyplate should be possible.

I would prefer front-slanted keys. My favorite are the HP41C "tall" keys, but the "not so tall" (as in the 41CV) are good enough.

I would prefer an overall size similar to Pioneers or 30B, a larger size, like 35S or 48/49/50 is cumbersome in my opinion.


I also vote for keys with the slanted fronts, allowing one shifted key plane to be marked on the keys like the 20b/30b and all pre-Pioneer machines. IMHO, removing the slanted key fronts starting with the Pioneers and again with the "stretch" Pioneers (better known as the 48 series) was a mistake because it basically eliminated the possibility of adding a third shift (a la 34C or 67) without significantly cluttering the space around the keys. I absolutely love soft keys and menus, however they should not be employed without first exhausting the physical keyboard positions, which provide two-keystroke functionality. I personally do not think that three shifts is unreasonable on the physical keyboard, if the key fronts may be labelled. (However, going further than that would be problematic. The extreme example of this was the Laitram XQ2 layout for the HP41 using its custom "Rubber Duck" overlay, which basically reduced the '41 keyboard to 16 positions and allowed each one to be a shift for all the others.)



Speaking of softkeys and menus, there's one thing that I'd really like to NOT be on softkeys. I'd like a 42S-ish calculator with a "real" alpha mode like the 41 or 48/49/50, instead of the 42S softkey-based alpha.

I'm not sure which key of the 42S I'd be willing to give up to have an Alpha key, though.


Yes, alpha entry was one of the very few things (apart from I/O, of course) in which the 42S was not as good as the 41C.


And, please, keep an important HP41 physical feature: Do allow for non-adhesive overlays! Rounded cases are nice, but as every WP34S user knows, are not good for plain vanilla overlays!


I don't expect a vote, but theres a couple of points i'd like to make:

When i'm programming or calculating at the kitchen table i'd like to have a huge keyboard with all the functions available without having to spell them out.

When i was running programs (mine or Kerber's) in the field and juggling plans, a field book, a calculator and pencil; "small is beautiful". The 41's two rows of assignable keys were always enough and the 42's one row was almost always enough.

To get that big beautiful four line screen and keep pocketability you may have to sacrifice a large number of keys and use more menu or alpha solutions. Either way; just make enough so i can buy one. OK?


OK, assume you want to stay within the lateral dimensions of a 30b or Pioneer with that large LCD, then 37 keys will probably be the maximum allowable. 31 of them will have fixed assignments and 6 are the softkeys. With two shift keys this would mean 29 primary and 58 secondary functions plus up to 18 softkey functions at a time on said LCD. Compare the WP 34S with three prefixes, 34 primary and 102 secondary functions and no softkeys.


Compare the WP 34S with three prefixes, 34 primary and 102 secondary functions and no softkeys.

I'd be counting CPX as an orthogonal fourth prefix and perhaps even -> as a fifth.

- Pauli

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