DM-15L Review

[Thomas Klemm]

(11-10-2024 01:41 PM)AnnoyedOne Wrote:  

(11-10-2024 11:01 AM)dm319 Wrote:  Yes, though the problem is calculators need cleared before exams to meet the UK requirement that nothing is stored on it that can be accessed during the exam.

How do they know? I'm sure they know how to check Casio's and TI's but a HP/SwissMicros?

That's very easy:

Make sure that the DM-15L is in run-mode.
Then press:
f CLEAR PRGM

Switch to program-mode:
g P/R

You see:
000-

This is proof that all the programs have been removed.

[Commie]

(11-11-2024 09:24 AM)dm319 Wrote:  ... but a modern scientific is literally the competition if you are a child at school.

So you want your child to have the best calculator money can buy, to be on top of everyone else?

[dm319]

(11-11-2024 05:38 PM)Thomas Klemm Wrote:  Make sure that the DM-15L is in run-mode.
Then press:
f CLEAR PRGM

Switch to program-mode:
g P/R

You see:
000-

I'm here just appreciating the colours.

[carey]

(11-11-2024 04:25 PM)Commie Wrote:  

(11-10-2024 11:57 PM)carey Wrote:  ...the 40 year old design of this shirt pocket calculator holds up quite well!

If electronics, mainly cpu's and memory capacity, had stood still without the evolution of electronics then I would say you have a good point, however, 40 years of evolution means that hp calculators are somewhat dated now.

Cheers
Darren

Darren, thank you for your reply.

It's possible that we may be mixing up hardware and software. The recent mix of 15C calculators (e.g., 15C CE, DM15L, PX-15C) are not running on 40 year old hardware (the 15C CE runs programs up to 200 times faster than the original 15C) and have benefited from the the evolution of electronics.

Remarkably, on the software side, the feature that all functions accept complex arguments is, 40 years later, still a distinctive quality of the 15C (and the 42S) compared to many or most newer calculator models.

Where I agree the design shows its age is that the program display only shows numeric key locations rather than alphanumeric function names (though the PX-15C provides both).

[Johnh]

The questions about school calculators led me to take a look at what is used in schools now. So many more options to explore now, at least for the higher courses with the advanced graphic machines.

Great learning tools, but I feel an unease with these latest Casios etc. It's like a restaurant where you can order and be served any mathematics that you want and have it presented to you perfectly on a plate.

But our classic programmable calculators let you get right into the kitchen and learn to cook for yourself, and create new recipes. I think that can be a more powerful learning experience!

[dm319]

(11-11-2024 08:51 PM)Commie Wrote:  So you want your child to have the best calculator money can buy, to be on top of everyone else?

To be honest I think the opposite is true, the more that is done in the brain the better it gets!

Hang on, does that mean I picked the worst calculator for my kid?

(11-11-2024 11:21 PM)Johnh Wrote:  The questions about school calculators led me to take a look at what is used in schools now. So many more options to explore now, at least for the higher courses with the advanced graphic machines.

Great learning tools, but I feel an unease with these latest Casios etc. It's like a restaurant where you can order and be served any mathematics that you want and have it presented to you perfectly on a plate.

But our classic programmable calculators let you get right into the kitchen and learn to cook for yourself, and create new recipes. I think that can be a more powerful learning experience!

So this evening, just for fun and for 'research' I did a GCSE Maths (calculator) paper from here:
https://qualifications.pearson.com/en/qu...ssessments

I wasn't especially good at maths, but had a go at paper 2. You guys will find it laughably easy. It probably didn't take much more than 10 minutes and I got 96% (well with a lenient marker) using the DM-15L. The main purpose of the exercise was to check there weren't some specific functions needed.

There are some nice problems in there that are something of a joy to solve using RPN.

I'll give A-level a try next!

[floppy]

Question:
- programs written in a DM15L can be transfered into a PC and back?
- are the programs compatible with DM41X ? (if using for sure the same functions or reworking a text file before transfer to the DM41X or from the DM41X).

[jthole]

(11-12-2024 07:29 AM)floppy Wrote:  Question:
- programs written in a DM15L can be transfered into a PC and back?

Yes. And Torsten Manz's HP 15C simulator is a nice help: https://hp-15c-simulator.de/

(11-12-2024 07:29 AM)floppy Wrote:  - are the programs compatible with DM41X ? (if using for sure the same functions or reworking a text file before transfer to the DM41X or from the DM41X).

Not really, but it should be easy to translate DM15L programs to the DM41X. The other way around would be more complicated.

Look here for a feature comparison between the HP-15C and HP-41CX:
https://www.hpmuseum.org/cgi-bin/compare...ne&diff=ON

The DM41X can load all of the optional modules mentioned, I believe.

[AnnoyedOne]

(11-11-2024 11:21 PM)Johnh Wrote:  I think that can be a more powerful learning experience!

I'm reminded (daily) of the humans on the spaceship in the movie "Wall-E". Machines do all the "grunt" work while the people laze around all day.

I'm not sure that the population is being "dumbed down" but that seems to be the case. Have your calculator/phone/AI/whatever solve your problems for you. No need for you to think.

Over history humans have learned more and more but we now seem to be heading in the other direction.

My 2c.

A1

[AnnoyedOne]

(11-12-2024 07:29 AM)floppy Wrote:  - programs written in a DM15L can be transfered into a PC and back?

Yes! With Pierre's speadsheet.

https://www.hpmuseum.org/forum/thread-22...#pid193243

Also to/from various emulators/simulators and the HP-15C CE.

A1

PS: SwissMicos has their own online only tool as well.

https://technical.swissmicros.com/decoders/nut/

[Commie]

(11-11-2024 10:31 PM)carey Wrote:  It's possible that we may be mixing up hardware and software. The recent mix of 15C calculators (e.g., 15C CE, DM15L, PX-15C) are not running on 40 year old hardware (the 15C CE runs programs up to 200 times faster than the original 15C) and have benefited from the the evolution of electronics.

A, would be, hp15c clone manufacture has no choice but to use the latest technology. As you are probably aware, clone designers emulate the original hp 4-bit NUT processor on an ARM/AVR processor which are much faster than the original, however, this speed increase is debatable because lcd screens are very slow, also high speeds shorten the keyboard debounce time and so the only option open to clone designers, who deploy emulation, is to slow the cpu down.

Because emulation is utilised, such as the hp15ce, the calculator offers nothing new over the original except some speed increase and extra ram and as I have said before, the original hp's software or firmware are getting old when compared to say the ti30x pro at 1/5th the price.

Cheers
Darren

[AnnoyedOne]

(11-11-2024 11:41 PM)dm319 Wrote:  ...I did a GCSE Maths (calculator) paper from here:

I downloaded the test papers and apart from one trig function I think any basic four-banger calculator with sqrt would do.

I may, or may not, take the highest level exam, with my TI-30, just to see how I do

A1

[Eddie W. Shore]

Excellent review, dm31.

Cheers to the family.

[carey]

(11-12-2024 01:21 PM)Commie Wrote:  Because emulation is utilised, such as the hp15ce, the calculator offers nothing new over the original except some speed increase and extra ram and as I have said before, the original hp's software or firmware are getting old when compared to say the ti30x pro at 1/5th the price.

All good and valid points, except...the TI-30X Pro accepts complex arguments only for arithmetic operators, square roots and powers, not log or trig functions as in the 15C. Hence, the point I made in both previous posts (copied below) remains unanswered. Despite 40 years of hardware evolution making possible low-cost scientific calculators with nice feature sets, the 40 year old complex function feature set of the 15C (important for EE's, scientists and others) has not been equaled in a current low-cost scientific calculator.

(11-10-2024 11:57 PM)carey Wrote:  However, for users who value the 15C feature that, except for statistical and matrix functions, all its functions accept complex arguments...

(11-11-2024 10:31 PM)carey Wrote:  Remarkably, on the software side, the feature that all functions accept complex arguments is, 40 years later, still a distinctive quality of the 15C (and the 42S) compared to many or most newer calculator models.

[Commie]

(11-12-2024 02:35 PM)carey Wrote:  .. except...the TI-30X Pro accepts complex arguments only for arithmetic operators, square roots and powers, not log or trig functions as in the 15C.

Forgive me if I'm wrong but complex trig/logs are at least first year degree level, maybe second year?. The thread starter has bought his son a DM15L and he only starts high/secondary school next year?

Cheers
Darren

[carey]

(11-12-2024 03:44 PM)Commie Wrote:  

(11-12-2024 02:35 PM)carey Wrote:  .. except...the TI-30X Pro accepts complex arguments only for arithmetic operators, square roots and powers, not log or trig functions as in the 15C.

Forgive me if I'm wrong but complex trig/logs are at least first year degree level, maybe second year?. The thread starter has bought his son a DM15L and he only starts high/secondary school next year?

Actually the thread began as a DM-15L Review in which the thread starter raised the complex variable handing of the DM15L:

(11-09-2024 04:41 PM)dm319 Wrote:  Despite being based on 43 year old technology, the DM-15L
beats every other modern scientific calculator in complex
number handling. The modern TI-30X pro mathprint and TI-36X
pro which I believe are top of the range scientifics can not
raise complex numbers to anything other than 1, 2 and 3.

You are forgiven :)

[Commie]

(11-12-2024 05:08 PM)carey Wrote:  You are forgiven

Ha, yes okay, I give in.

[dm319]

(11-12-2024 01:03 PM)AnnoyedOne Wrote:  I'm not sure that the population is being "dumbed down" but that seems to be the case. Have your calculator/phone/AI/whatever solve your problems for you. No need for you to think.

It's a common misconception over the last few thousand years we've become more intelligent. We probably haven't, even if we've had much better access to information.

(11-12-2024 01:21 PM)Commie Wrote:  Because emulation is utilised, such as the hp15ce, the calculator offers nothing new over the original except some speed increase and extra ram and as I have said before, the original hp's software or firmware are getting old when compared to say the ti30x pro at 1/5th the price.

I agree with you in the sense that the world of RPN hasn't moved on that much. I picked the DM-15L quite specifically for my son because it looked like it would meet almost all the requirements for GCSE and A-level maths, while not looking obviously too sophisticated. It may still fail on both of these counts though!

Some people have taken RPN in new and modern directions. Thomas Okken took HP-42s and gave it quad precision, augmenting it with formulae and directories in the form of Plus42. The WP43 and C47 teams have really pushed the boat out with precision, user interface and a metric f ton of functions. HP have also had newer machines - the HP35s for example, but not to mention all the RPL series and Prime.

Personally, I have my own ideas of a modern take on these calculators. I'd love to see extensibility of something like the HP-42s to using modern programming languages, so we can drag and drop new functions onto the device, and use as much memory as we like to make complex and accurate algorithms for all sorts of things. Another thing I'd like to see are cheap RPN scientifics for school children.

The example with the complex functionality of the DM-15L is more to say 'the DM-15L/HP-15c can still stand proud on some things'. I'm not saying it is better.

Maybe I should have given a bit more balanced context. The answer to cos(1.57079632) is a tricky one.

fx-6300G: 6.8e-9
fx-115W: 6.795e-9
fx-992s: 6.7949e-9
fx-85gtcw: 6.794896619e-9 (all digits accurate and more available)

DM-15L: 6.795e-9

There has been a lot of progress with Casios!

On the other hand, the fx-992s, which was the advanced version of the top-of-the-range Casio scientific (fx-991s) and 3rd generation to handle complex numbers can't solve:

sqrt(-1)
(1+i)^(anything)
trig(1+i)
it will do squares though

Another thing I don't approve of is the fakery with making the calculators appear more accurate than they really are, by rounding at some times and not others, and trying to give results as surds and fractions of pi, and occasionally failing badly at it.

(11-12-2024 01:54 PM)Eddie W. Shore Wrote:  Excellent review, dm31.

Cheers to the family.

Thank you Eddie! Lets see how it goes...
My other son has requested I engrave his fx-85gt cw this saturday.