HP Forums

Is there anyone out there that can customize or custom build an RPN/keystroke programmable calculator. I have a collection of various HP's and wondered if anyone has or could "Frankenstein" together the ultimate RPN? For example, I love the new 35s except for the lack of matrix support and the R>P P>R key. I think the 42s is almost perfect but 7k of memory merely teases my appetite for programming capacity...and so on it continues from various other models too. I found a mock up of a combination of a 35s and a 42s that the author labeled a 43S. I thought is was really cool and hit the nail on the head. If anyone knows of the source please let me know the background. Any thoughts, interest, or direction would be greatly appreciated!

Eric Smith's DIY project is heading toward what you are after. Hopefully he is getting close.

Hi.

Quote:

---

I think the 42s is almost perfect but 7k of memory merely teases my appetite for programming capacity.

---

For what it's worth, I miss I/O capabilities more than internal memory...

Also, the WP34S is an outstanding work of art and technology from two contributors here, and it is surely a must try. We must consider the fact that it is possible to provide firmware once the hardware is provided.

Cheers.

Iuiz (Brazil)

Edited: 22 Oct 2012, 8:55 p.m.

When there's no missing feature left we could request, we still can complain about the calculator being too complex to use.

;-)

Yep, you're right... Customers are never satisfied.

Very true.

Jason,

There have been many calculator 'projects' wandering around these parts for a decent fraction of a decade and haven't gone anywhere because nobody wants to spend money and writing firmware is more fun than actually doing proper keys, cases, etc.

The software (firmware) isn't too hard to write - a bit harder to really do it right. [Adding Solver functionality etc. is a separate matter.] Either an existing HP calc can be truly emulated or a new calc created based on some long precision math libraries and some sort of programmability added.

The real issue is to make a "I want to actually use this calculator" device that has a good keyboard, display and case and "looks production". Just doing labelled keycaps alone with proper key clicks is a major undertaking esp in small volumes.

[My own dream calculator: big traditional Enter key w/4-level RPN (XYZT+L) and postfix function operations for 'daily driver' work, but user programmability using HP71B BASIC... in a package a la HP42S, with serial port and uSD card use.]

If there is anyone to achieve this goal it'll be Eric Smith with his projects.

Bill Wiese

San Jose CA

Would you settle for USB (as a device) rather than the serial port?

If you want BASIC programmability in a 42S package, would you want to be to enter/edit the BASIC programs on the calculator itself, on a PC and downloaded, or both?

Hi Eric,

>>Would you settle for USB (as device) rather than serial port?

As ye old saying goeth, "Beggars can't be choosers." ;-)

USB device is nice for moving files to & fro the calc [see my answer to your other question below, but serial I/O and few bits' GPIO are wonderful for control gigs.] - but, hell, sneakerware uSD card movement between devices is fine for me.

I myself would rather have serial I/O than USB MSC card access

Doubt your uC has USB host capabilities but if it did, hosting a a USB serial profile could perchance alleviate some grief.

>> If you want BASIC programmability in 42S package, would

>> you want to be able to enter/edit BASIC programs on the

>> calculator
itself, on a PC and downloaded, or both?

Again, PC downloading is somewhat frou-frou to me if (u)SD card in FAT32 can be read/used by calculator as Hp71ish storage that's laid over a FAT32 filesystem. If one has to pull a uSD card in/out of PC slot, no big thing to me.

Entry of BASIC programs from KB seems necessary even if a tad painful (imagine "stranded in a desert" for necessity). Major BASIC keywords should be able to be entered w/one-shifted keystroke (PRINT, IF, THEN, ELSE, LET, LEN$/MID$/LEFT$/RIGHT$/INSTR$/CHR$, log, trig etc.).

Some other notes..

- While Hp71B BASIC is nice, others could work. I seem to recall
a UBASIC open source?? with arb precision math. But I think we all agree HP71B BASIC (with add-ons) is a pretty fine gen purpose BASIC for crunching.

- Regular nonprogrammatic keyboard work should, however, not be "Hp71b expression style" but good ol' 4-level XYZT+L RPN, big ENTER key, with log, trig & other functions running postfix on stack just like plain ol' HP calc. Easy KB access to LastX, R^, Rdn necessary.

- a separate "EXPR" key should allow string entry of algebraic expression to be evaluated using vars/memories.

Regards,
Bill Wiese

San Jose CA

Quote:

---

and "looks production"

---

When a company I was working for in the late 1980's was looking into custom double-shot keys and a custom LCD, it seemed very easy to get it done, but it was a couple thousand dollars or more for NRE. Lexan overlays' NREs are less.

I would much prefer a serial port instead of USB. SD or uSD would be nice.

Edited: 24 Oct 2012, 12:53 a.m.

as luiz said; the 34s sounds like what you are looking for, a miscegenation of the 16, 42, and much more- in the body of a business calculator. it's very inexpensive and if you are smarter than me, you can throw out functions that you don't use and probably have about 4k of user program/data memory. mass storage is a bit circuitous but it's amazing that they got it at all, since the calculator hardware was not designed with that in mind. get the 30b platform. it has better keys than the 20b.

Thanks Jeff. I'll check it out.

thanks Luiz. I am chatting with Don @ International Calculator about performing the operation.

How true! How true Thomas.

You are welcome.

By the way, I did not mean to give short shrift to wp34s. It is a wonderful project that could very well be all that you need. But from reading your message, I got the feeling that you were looking more for what it appears DIY5 is heading for.

Thanks Bill. Money is always a concern :( I'd rather pay a few hundred sheckles for a really good unit than $50 for one that is okay. Unfortunately mass production and sales just doesn't roll that way. I use an HP everyday. I love keystroke programming and the ability to customize programs and routines without being a "programmer". As I think more about the "custom" subject I realize that "pocket-sized" portability is an extremely desirable quality to a land surveyor. I could really use a 15c with the modern version of Keystroke programming (Like the 35s, and equation library and "in program" equations (HP 35), with a matrix capacity of 25x25 (8x8 is cool but slightly undersized), and an indirect register bank as large as possible (10,000 registers?) I use my indirect registers on the 35s to store coordinate pairs as complex numbers. Along those lines a micro SD card would be a nice place to have additional storage registers and program memory. I envision using the mSD card to transfer coordinate files to and from a desktop or other users. Whew! That's a lot of gas :) Anybody else care to weigh in????

thanks db. I have crammed 29k of info and programs into my 35s and could keep going. I'll check out the 34. I'm wondering if I am overburdensome or klutzy with my programming????

From these numbers, it looks like WP 34S will not fit your bill. :-(

Quote:

---

I realize that "pocket-sized" portability is an extremely desirable quality to a land surveyor. I could really use a 15c with the modern version of Keystroke programming (Like the 35s, and equation library and "in program" equations (HP 35), with a matrix capacity of 25x25 (8x8 is cool but slightly undersized), and an indirect register bank as large as possible (10,000 registers?) I use my indirect registers on the 35s to store coordinate pairs as complex numbers.

---

I looked at Stefan's site. What a wonderful resource. Thanks!

Quote:

---

thanks db. I have crammed 29k of info and programs into my 35s and could keep going. I'll check out the 34. I'm wondering if I am overburdensome or klutzy with my programming????

---

I wish there was a way to back 35S programs other than paper/Word documents.

If you need more matrix functions you might want to look at Article 886. One caution -- I wrote it to interface with Stefan's original version. It has been quite a while ago but I think that he made some changes in his program that would require some equivalent changes in my interface with his program.