The HP-65 was not only HP's first programmable scientific, but it could also read and write magnetic cards. There were several 'pac's of cards allowing it to tackle financial, astronomical, aviation, electrical and other speciality field calculations. The buttons were double shot and have a lovely tactile click. The red LED screen is remarkably crisp and easy to read.
I think I like the buttons and the highly-specialised functionality. At least that's what I think when people say 'what's the point, you have a far more powerful calculator in your pocket already'. Yes, one without buttons.
It is! Not mine sadly, but amazing to see such a thing. I didn't have much time so apologies for not stopping down enough - I didn't realise at the time!
These are the tests which can give you quite a good profile and accuracy rating for your financial calculator. Any more contributions and confirmation are very much appreciated and I will update the swissmicros page (though I may need to move it off there at some point). ``` | # | Ref | N | I%YR | PV | PMT | FV | P/YR | Mode | |----|------------|--------------|-----------|----------|--------------|-----------|------|-------| | 1 | DM | 38 x 12 | 5.25% | 270'000 | ? | 0 | 12 | end | | 1b | DM | 38 x 12 | ? | 270'000 | -14'584/12 | 0 | 12 | end | | 2 | SlideRule | 360 | 15% → 12% | 100'000 | ?-? | 0 | 12 | end | | 3 | Kahan 1983 | 60x60x24x365 | 10% | 0 | -0.01 | ? | =N | end | | 4 | DM | 480 | 0 → ? | 100'000 | ?→ PMT | 0 | 12 | end | | 5 | Dieter | 10 | ? | 50 | -30 | 400 | 1 | end | | 6 | Dieter | 10 | ? | 50 | -30 | 80 | 1 | end | | 7 | A Chan | 10 | ? | -100 | 10 | 1e-10 | 12 | end | | 8 | Miguel | 32 | ? | -999'999 | 0 | 1e6 | 1 | end | | 9 | DM | ? | 25 | 100000 | -2083.333334 | 0 | 12 | end | | 10 | DM | ? | 25 | 100000 | -2040.816327 | 0 | 12 | begin | | 11 | robve | 60x24x365 | 1/6% → ? | 0 | -0.01 | ?→ FV | =N | end | | 12 | robve | 40 | ? → I%YR | 900 | -400 | -1000 → ? | 1 | begin |
2: https://www.hpmuseum.org/forum/thread-20707.html 3: https://www.hpmuseum.org/forum/thread-1012.html 5, 6: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv021.cgi?read=234439 7: https://www.hpmuseum.org/forum/thread-18359-post-161549.html#pid161549 8: https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.cgi?read=120592 11, 12: https://www.hpmuseum.org/forum/thread-16565-page-2.html ```
Puzzle 2 is from here, and needs you to calculate PMT given n = 360, I%YR = 15%, PV = 100'000, FV = 0, then calculate PMT, but with I%YR = 12%. Subtract the two results, and put that back into PMT, then change n = 36 and I%YR = 15% again, and calculate PV.
Puzzle 3: you may need to divide I%PY by N depending on how your calculator handles i vs I%YR and what the limit is on P/YR.
Puzzle 4 needs you to calculate PMT first given I%YR = 0, then re-input this back into PMT and calculate I%YR. On the HP-12c this is best done by pressing x<>y twice before putting back into PMT.
Puzzle 11: calculate for FV first, re-input back to FV and compute I%YR.
Puzzle 12: calculate for i first, re-input back into i and compute FV.
The other puzzles are just a solve for '?'.
They can be a bit confusing, so I also did a couple of videos here and here solving them on a DM-42 and HP-12c.
Really glad you enjoyed it!! It's a very very small niche of people I think.
Totally would love to work on an edge cases database! It is no secret (posted on swiss micros forum), but I can do a submission here if that works?
It's actually a really nice bit of software. Really nice range of functions.
Yes, looks like coated aluminium - not unlike a can but a little thicker and with no sharp edges. I've not seen these before but I think they are disposable/recyclable - i.e. a replacement for a plastic cup and far more pleasant to drink from. I took mine home as a souvenir, but I have had to unsquish it today taking it out of hold luggage.
Yes, in fact before I got my DM42 I had one holiday where we had no internet access in the evenings and as the children were small and slept early, I didn't have much to do but I was able to learn a lot about using and programming free42.
You do have to remind yourself at the beginning that you're using RPN, but after a while it feels a bit like working sums out on paper.
A random shot of my calculator 5000 miles from home while I enjoy a beer near the Pacific. We had been discussing how much water was on earth and what size of a ball it would make. I have no affiliation with the brewing company so apologies for the product placement.
Just to clarify - means two taps of the esc key in succession will clear highlighting (ps I'm curious how other people do it!).
nmap <esc><esc> :noh<return>
Yes, I also have caps mapped to esc, but done in keyboard firmware so that holding it functions as ctrl.
In neovim I have two escapes mapped to :noh
I tried to play this on an original IBM PC. Without a mouse and only 4 colours. It went badly.
Yeah, I think they need to tune their nibs before they let them out. No such thing as too much flow - just too little paper.
That's lovely - these calculators are very 'dad' style to me also (though my dad had a 70s style Casio). There's something about the voyager HP calculators with their landscape format - they are really satisfying to use, I can see why he kept it on him!
It's a Stilform fountain pen. They are a recent make using machined parts and bock nibs with a nifty magnetic cap. I'm having slight issues with the bock nibs though - they are going to need a bit more work to keep the flow how I like it.
I always thought of financial calculators as a sort of gelded single-function function machine and I didn't really get them. However, that would ignore the vast number of models available from HP, and that their second ever pocket calculator was a financial one. It turns out that solving the time value of money equation is non-trivial, and the work done on that probably paved the way for calculators with a solver.
The other thing I didn't appreciate until I had to use it, is that the interface of the 12c - with the 5 buttons in the top left for n, i, pv, pmt and fv is peak user interface. Press once to input data, but a second consecutive press of these buttons will trigger the solve and drop the result into x. It's perfect, and means you can solve and use all the calculator functions and stack continuously. Most modern methods use a table, which is hard to extract and input information from the calculator.
This might be the best looking graphing calculator I've seen.
HP's most accurate financial calculator, oddly enough, and despite only returning the ceiling of solve-for-n.
These were such great machines, so far ahead of their time. I had a 3a, and nothing has beaten the Agenda program on it. I think part of the reason it was so good was that it wasn't a touch screen and the keyboard control was so well thought out, especially tab to bring up a monthly calendar. And what modern calendar has a year view that is useful?
That is a well-filled pen! It looks like others have said this, but nothing has ever beaten my 90s PDA for organising my life.