HP15C CE Finance Pac

[Divasson]

After Geoff Quickfall's wonderful Aviation Pac (for which we have ordered silicon overlays like the HP16c overlay), we said "why not a Finance Pac".

Finance programs for the HP15c are readily available, but are long, cumbersome to enter and prone to errors. We decided to put together some of the main ones and create a suitable overlay for them too.

Programs require at least 19 free registers and occupy 407 program steps. Finance Pac runs on 15.2 mode (so you need to set the calculator on 15.2 mode prior to upload the memory file). Programs in yellow in the overlay (on the keyboard surface) are launched by clicking on the function key (A to F) or GSB number. Programs in blue in the overlay (slanted part of the key) are launched by clicking GSB .number.

Time Value of Money: function keys A to F. Taken from the HP15c Advanced Functions book with a change to the error exit label code.

NPV: Up to 18 years + initial flow. Enter number of years in Reg. .9 ; initial cashflow in reg. 0; annual cashflows in registers 1 to .0; discount % in X; returns NPV in X. Own development

IRR: same registers as above; use f SOLVE .1 (NPV) - returns IRR in X

Weighted average: enter pairs of numbers with the statistics key: volume ENTER price Sigma, volume2 ENTER price2 sigma, ..., Renders sum of volumes in Y and weighted average of prices on X. Own development.

- Sales tax. (VAT in Europe) Introduce sales tax % in reg .8; gets value including tax from X; returns value before sales tax in X, sales tax in Y. Own development

+ Sales tax. Introduce sales tax % in reg .8; gets value before sales tax from X; returns value including sales tax in X, sales tax in Y. Own development.

MM.DDYYYY to Julian Day number. Taken from HPmuseum.org (15C) MM.DDYYYY or DD.MMYYYY to Julian Day [Stack-Only] from Nick

Julian Day number to MM.DDYYYY - Own development. Horrible programming, using registers! - you are welcomed to improve it.

DDAYS: difference between days in format MM.DDYYYY in X and Y. Taken from HPmuseum.org (15C) Delta Days [12C Actual Day Basis] from Nick. Uses MM.DDYYYY to Julian Day number

DATE+: date in Y in format MM.DDYYYY, increase in X. returns DATE+increase in MM.DDYYYY format. Own development. Uses Gregorian to Julian and Julian to Gregorian routines

Day of Week : enter date in MM.DDYYYY in X, returns day of week with Sunday=0, Monday=1; Saturday=6 - own development. Uses Gregorian to Julian subroutine. Thanks to Jukka Levänen who spotted a rounding error!

Pending: to document validity range of Gregorian date to Julian day number and Julian day number to Gregorian date.

You can find the Finance Pac and the documentation (thanks to Torsten Manz and his HP15c simulator!) here:

Finance Pac
Finance Pac documentation
Finance Pac Overlay preorder page



Overlay colors will be yellow for the surface of keyboard labels, white for the top of key labels, and blue for the slanted part of keys - just like the HP16c overlay.

Thank you for your feedback. As the HP15c is open, we can change the pac as needed and all improvements or corrections will be updated in the google drive site.

[Geoff Quickfall]

It is really a lot of fun using the cable to store and recall calculator states on the 15CE.

At the moment it is a command window function on a windows machine. But that reminds me of my DOS 1.1 days!

Being able to convert your 15CE into differing versions really expands the capability of the calculator.

Let’s get some more pacs running for this. We need the surveyors and engineers to get into the game also.

Cheers

Geoff

[Divasson]

There is already a prototype of a simulator that records and reads HP15c CE's memory files. Hopefully it will be ready soon!

[jthole]

This is the calculator I have been waiting for, but I’d want a physical keyboard, no overlay.

Maybe Moravia is listening ;-)

[rprosperi]

(08-30-2024 01:30 PM)jthole Wrote:  This is the calculator I have been waiting for, but I’d want a physical keyboard, no overlay.

Maybe Moravia is listening ;-)

I'd say try using one of these overlays before dismissing it, it is definitely not your father's overlay; these silicone overlays are great, and truly should really have a different name as they share almost nothing with the feel of overlays from the past. Jose has done an excellent job of producing highly usable 'glove like' overlays which fit and feel great.

[jthole]

(08-30-2024 10:18 PM)rprosperi Wrote:  I'd say try using one of these overlays before dismissing it, it is definitely not your father's overlay; these silicone overlays are great, and truly should really have a different name as they share almost nothing with the feel of overlays from the past.

Thanks ... I am certain that Jose did a great job, and his overlays (also the 16C one) look high quality in the photos.

I just wish Moravia would create either a 12C Enhanced (with the six basic trig functions on the keyboard, and as programmable instructions), or a 15C with the very useful date calculations and enhanced percentage functions (like the clever sales tax routines).

I would be most happy with a 12C Emhanced, I think.

[Geoff Quickfall]

So much has been done on the aftermarket designs that is nice to get a barebones 15 with expanded memory.

But, I have to agree, wouldn’t the 15CE be nice with a clock ala the 41CX with some functions.

Swiss micros did this with their DM42. Added the 41CX time functions and a clock.

But a traditional HP 15C with expanded memory, alpha numeric display and a clock with a piezo (bender) plus the USB support.

Cheers

P.S. the overlays are excellent though!!! I was thinking more along the lines of a 41C blank overlay which one can label.

May have to see about cutting some but for that, I would need a CNC. “Honey, can I have a 3D printer and a CNC??? :-)

[AnnoyedOne]

(08-31-2024 04:10 PM)Geoff Quickfall Wrote:  ...wouldn’t the 15CE be nice with a clock...

I second this! Moravia are you reading this?

The HP-15C CE (ATSAM4LC2CA SoC) does contain a RTC (Real Time Clock). If the hardware has a 32kHz crystal present it shouldn't be too hard to implement.

A1

[sirplatypus]

Will this overlay work on a DM15L? I’m sure the physical overlay probably won’t be sized correctly, but the firmware looks very appealing.

[rprosperi]

(09-12-2024 03:36 PM)sirplatypus Wrote:  Will this overlay work on a DM15L? I’m sure the physical overlay probably won’t be sized correctly, but the firmware looks very appealing.

As you note, the DM15L and 15c have different geometry, despite being quite similar, so the overlay will not fit tightly/properly.

This Finance Pac is not firmware, it is a collection of end-user programs, so yes they can be used in a DM15L, however you will have to key them in manually since the 15c CE memory dump format is unfortunately not compatible with that of the DM15L.

[dmh]

Will long term use of overlays wear off the print on the keys?

I assume the keys on the 15C CE are painted and not double shot.

[Geoff Quickfall]

The only caveat to the programs are available for all 15’s designed and built is the following:

The aviation pack takes advantage of the expanded memory available to the 15CE. The code is 497 lines beyond the standard memory capabilities of the 15C and the DM15 (i think, will have to check mine out).

Easily remedied by picking and choosing which standalone routines to use.

Geoff

[rprosperi]

(09-25-2024 12:09 AM)dmh Wrote:  Will long term use of overlays wear off the print on the keys?

I assume the keys on the 15C CE are painted and not double shot.

Yes, the 15c CE keys are painted and not double-shot.

Assuming you mean wear of the physical keys under the overlay, it's unlikely use of the overlay itself will affect them much, but not impossible. Most often, it's the grease, sweat and acid from your fingers which causes key labels to wear, and the overlay would in fact protect them from that.

That being said, I'm not aware of any info on extended use of a silicone label and related key wear, so impossible to say for sure. But if you plan to mount and use one of these overlays for an extended period, I'd recommend you thoroughly clean the keyboard with something like a baby wipe (and NOT alcohol) to remove any oils, etc. from prior use, which would be trapped between the silicone and keys and possibly lead to label erosion.

[Maximilian Hohmann]

Hello!

(09-25-2024 12:46 PM)rprosperi Wrote:  Most often, it's the grease, sweat and acid from your fingers which causes key labels to wear, ...

And not to forget, pushing the calculator into and out of it's case or into a shirt or trouser pocket will also wear off the printed labels. Compared to that, using the overlay should only result in minimal wear.

Regards
Max

[Divasson]

A customer signaled a bug in the program: the file was using in the TVM GTO 0, while the documentation was using GTO .0

(I would mention the customer's name to thank him but I don't have his authorization yet)

There is a label 0, used by the weighted average program, but that's not the one we're addressing.

The original TVM in the Advanced Functions manual uses a GTO to a label that is NOT used anywhere, as a way of catching error conditions and display an "error 4" message. In this case we have substituted this label by .0, which was unused in the rest of programs.

The bug (addressing lbl 0 which is a used label) was mostly harmless - it would only happen when there was an error anyway in the TVM!

Anyway, here is the link to the corrected Finance pac

[sirplatypus]

Anyone have a program for the 12c’s amortization function?
Also, I have coded a subroutine using label .3 for ddays on a 30/360 schedule, called by the ddays program to display in the y register similar to how the hp 12c does it. When I digitize the program steps I will link it so people can use or optimize it.

[Divasson]

The actual overlay:

[Johnh]

I have a couple of general questions about the overlays, (which look very good indeed in the photos!)

In relabelling a key, is it the general idea that it then leads to a subroutine addressed by a LBL?
Are there any issues with the original hardware function of the key, which presumably is still active?
How physically, are new labels on the actual keys attached? is it a seperate small piece stuck to the key? or is it a bulge in the surface of the continuous overlay? How durable are they?

Sorry if these questions are covered elsewhere.

[Divasson]

Hi,

Nothing is changed in the calculator (except for the programs!).

The principle of the overlay: the yellow programs on top are launched by GSB - key; the blue programs are launched by GSB "." key.

The overlays are made of yellow silicone rubber moulded. It is then given 3 coats of color: white, blue and black - and these are removed with laser.

I have been using these overlays since august last year and no one has peeled off so far. Does anyone else's ?

[Divasson]

Hi,

Nothing is changed in the calculator (except for the programs!).

The principle of the overlay: the yellow programs on top are launched by GSB - key; the blue programs are launched by GSB "." key.

The overlays are made of yellow silicone rubber moulded. It is then given 3 coats of color: white, blue and black - and these are removed with laser.

I have been using these overlays since august last year and no one has peeled off so far. Does anyone else's ?