Calculator Community

The TI-86 is my absolute favorite calculator. I find it a pleasure to program for, I love the custom menu buttons, and I love the screen compared to that of the 83/84. I love the design, the uniform buttons and dark color scheme look very professional. This is my second one, after the screen died in my original baby that got me through high school and college. Which leads me to another thing I love about it, they are dirt cheap on eBay. Most are under $20.

Back in my college days, I saw somebody online had modded theirs with the frontlight from a GBA SP. The AGS-001, not the AGS-101. That was brilliant. I did a ton of calculator programming and math in low-light conditions at the time. Lounges in the dorms, during lectures. A calculator with a lit screen would have been awesome. I know all three major brands have options like that now, but it was pretty novel at the time. I think the only one out with a backlight was the Casio 9860 Slim, which was quite pricey. Unfortunately, even a broken GBA was outside of my broke college budget, and those tri-wing screwdrivers were not common yet. So, the dream faded.

Until, for some reason, a couple weeks ago. I do not know why it popped back into my head, and I could not find the source of the mod again for the life of me. But I knew I had to do it. And these days, you can get aftermarket GBA parts super easy and cheap. I still had my old 86, and I took it apart for proof of concept work. I tried every single test point for something that just turned on and off with the calculator, and could not find a single thing. Well, at least not anything without a signal from it. So, I resigned to just using a switch. Which I remember is what the original mod also did. I hid it in the battery compartment. It works fantastic. I wish I did this 20 years ago. There are a few specks of dust on it, and the frontlight makes them hugely visible. I'm going to get them off, but I'm out of Rodico at the moment. Anyway, just thought I'd share.

Found my old grade school calculator while going through some drawers. It's not programmable or retro (yet) or valuable, but it served me well for many, many years.

Pretty sure I learned the pattern for incrementing binary numbers on this thing while I was sitting bored in study hall before I even knew what binary was.

Spotted this at my local flea market. My first VFD display!

Yes it might not appear to align right, but that's only because the ruler is slightly above the calculator.

My calculator is exactly 178mm long, which is the definition of the length of one banana...

http://bananaforscale.info/#!/convert/length/1/bananas/millimeters

I added a few effects and stuff to my previous calculator demo, along with a signature line.

The weird symbol in the middle of the screen towards the end of the demo is literally Casio's text mode entry flashing cursor.

Shame on Casio, they knew...

I couldn't find the exact pixel dimensions for this calculator, so I just measured it myself.

1 Centimeter = 22 Pixels, exactly.

Edit: It might not appear in the photo to be an exact alignment with centimeters, but that's all because of the ruler sitting a little higher than the screen and the camera optical focus and crap.

Indeed, it's exactly 22px/cm

No manual, just past experience with other graphing calculators and experimental programming.

Enjoy...

Yes, 355÷113 is very close to π, but is not equal to π

So how does it get things 'right' for cos(355÷113), but not right for sin(355÷113)?

And why is the error of π-355÷113 exactly the same as the error of sin(355÷113)?

I sense some fuckiness of how they handle π...

The calculator as a whole seems to work perfectly, but can anyone explain Casio's choice of the shape of their flashing text entry cursor?

cross-posted from: https://lemmy.bestiver.se/post/202472

DM50 Calculator

Comments

It's the one on the left. We're allowed any calculator that's not programmable and cannot store text. The Elektronika can be programmed though it cannot store a program when turned off.

Nevermind the Casio's ability to solve, integrate, derivate, deal with complex numbers and matrices and more

Crossposted from https://lemmy.world/post/24154232

cross-posted from: https://lemmy.world/post/23724729

My dad says he's never replaced the battery in it. We saw this in a home video and laughed when we found the still uses it 40 years later.

For testing:

The official Swissmicros 2-line firmware dropped on the Winter Solstice as an early Christmas present. It also has a nice set of constants and conversions.

I'd been toying with the idea of what RPN calculator a kid could use at school here in the UK. I thought the sticking point would be that most RPNs are programmable, but turns out that isn't an explicit exclusion on the JCQ calculator guidance for GCSE and A-level exams. They can also use graphic calculators. There is a hard no on CAS. The HP-15c seemed the least likely to cause issues with invigilators, so went for this. We'll have to see if it works out though.

This is the calculator that my father bought for his senior year of high school in 1974. He showed it to me when I was four and I remember being amazed that a little box could add and subtract, captivated by the tiny red numbers. It was a few months later that he brought home our first computer, a Texas Instruments TI-99/4A, and I was again smitten. So much of the trajectory of my life can be traced back to those two objects.

When I opened the unit up I was not too terribly surprised to see a set of four AA batteries from the late 80's still installed, but I was very lucky that they hadn't leaked. I popped a new set in and it powered on with no issues. I played with it for a moment, the first time I had ever pushed the buttons on it, and placed it in the closet. I know it will be the perfect phylactery when I become a lich.

Originally posted by @HootinNHollerin@lemmy.world to !science_memes@mander.xyz

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.

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.

RPN83P running on the TI-83 Plus