Design for a simple, entry-level RPN calculator



#86

A simple scientific, 4-register stack calculator with statistics but no programming. 10 memory registers with storage and recall arithmetic.

ES RPN 10

_x^2 _______ ø^-1_____ HYP____ R(up)______FIX____ STD_
[SQRT_ ]__[__ ø_ ]__ [x<>y]__ [ROLL ]__ [_EEX]__ [_ Pi_ ]

Sigma- XROOT ASIN ACOS ATAN e^x
[Sigma+] [ y^x ] [ SIN ] [ COS ] [ TAN ] [ LN ]

10^x >H >HMS >P >R
[Shift] [ LOG ] [ 7 ] [ 8 ] [ 9 ] [ ÷ ]

CLStat x! >DEG >RAD % %CHG
[ CLx ] [ STO ] [ 4 ] [ 5 ] [ 6 ] [ x ]

OFF CLReg DEG RAD PDEV r/Sxy
[ ON ] [ RCL ] [ 1 ] [ 2 ] [ 3 ] [ - ]

Lst x MEAN SDEV SUMS L.R.
[ ENTER ] [ 0 ] [ . ] [ +/- ] [ + ]

Notes:
ø = Lower tail Normal Distribution with mean = 0, variance = 1
ø^-1 = Inverse lower tail Normal Distribution with mean = 0, variance = 1
PDEV = Population Deviation of x and y
SDEV = Standard Deviation of x and y
SUMS = Sigma(x) and Sigma(y)
Sxy = Sigma(xy)
L.R. = returns a and b in y = ax + b


(Sorry that keys don't align perfectly - I don't know how to get things to "line up" and I used the "pre" tags)


#87

Why not use the 30b keyboard layout for this? Your suggestion has 35 keys, the 30b has 37 so there isn't a huge difference there. The big advantage is the 30b hardware is available and more than capable of such a device and most of the firmware is written already :)

Why no GRAD mode?

- Pauli


#88

Quote:
Why no GRAD mode?

Does anybody besides artillery gunners use that?


#89

IIRC, we had this discussion about GRAD here many months ago already. Perhaps I'll succeed in excavating.

#90

at least every german surveyor needs GRAD because they calculate with 400 GON instead of with 360 DEG. Funny enough GRAD is the german word for degree. Can be confusing.

#91

I was going for a 15C layout at first.

We could switch out >DEG/>RAD for GRAD mode and RAN# (random numbers). It is a challenge to fit everything you want on a limited amount of keys.

#92

This is an attempt to redo the design based on the 30b calculator (still no programming):

--------------------------------------

ES RPN 10II

XROOT x^2 Phi^-1 >HMS >Polar DATE+
y^x Sqrt Phi >H >Rect DAYS

ASIN ACOS ATAN 10^x e^x 1/x
SIN COS TAN LOG LN Pi

Last X R-Up FIX STD Cl Regs
ENTER R-Down x<>y EEX < --

Sigma+ DEG RAD GRAD x!
STO 7 8 9 ÷

Sigma- % %Chg %T RAN#
RCL 4 5 6 x

COMB PERM Clr St r/Sxy
Shift 1 2 3 -

OFF Mean SDev PDev L.R.
ON/C 0 . +/- +


--------------------------------------

Phi = Normal Distribution Lower Tail
Phi^-1 = Inverse Normal Distribution Lower Tail
DATE+ = Add days to date code mm.ddyyyy (or dd.mmyyyy international editions)
DAYS = Days in between dates
(** These four functions are personal favorites of mine!)

Added: Gradian mode, Combination, Permutation, DATE+, DAYS

#93

I guess that's the way it should have looked:

  x^2       Phi^-1       HYP       R(up)       FIX        STD
[ SQRT ] [ Phi ] [ x<>y ] [ ROLL ] [ EEX ] [ Pi ]

Sigma- XROOT ASIN ACOS ATAN e^x
[Sigma+] [ y^x ] [ SIN ] [ COS ] [ TAN ] [ LN ]

10^x >H >HMS >P >R
[Shift ] [ LOG ] [ 7 ] [ 8 ] [ 9 ] [ ÷ ]

CLStat x! >DEG >RAD % %CHG
[ CLx ] [ STO ] [ 4 ] [ 5 ] [ 6 ] [ x ]

OFF CLReg DEG RAD sigma r/Sxy
[ ON ] [ RCL ] [ 1 ] [ 2 ] [ 3 ] [ - ]

Lst x MEAN s SUMS L.R.
[ ENTER ] [ 0 ] [ . ] [ +/- ] [ + ]

Notes:
Phi = Lower tail Normal Distribution with mean = 0, variance = 1
Phi^-1 = Inverse lower tail Normal Distribution with mean = 0, variance = 1
sigma = Population Deviation of x and y
SUMS = Sigma(x) and Sigma(y)
Sxy = Sigma(xy)
L.R. = returns a and b in y = ax + b

If true, the distribution of various functions looks a bit arbitrary to me. Of course, personal preferences vary. Anyway, however, I second Pauli's vote for using the HW of a 30b for your design.

FWIW,

Walter

P.S.: Remember also while designing calculators: Counting is the fundament of math ;-)


Edited: 3 Nov 2011, 6:23 p.m.


#94

To me "entry level" means a cheap MSRP, i.e. $19.99 or less. Anything more, and you might as well just buy a 33s and not use the programability. Also, I could care less if a calculator has a Grads mode or the Normal Distribution.


#95

I agree. Since obtaining an HP-45 some time ago, I've thought a "cheap & cheerful" calculator with HP-45 functionality would be good, i.e. a "quick access scientific banger" - more complex stuff gets done on a computer anyway. And it could be in the hardware of the current HP-10s.

If HP had kept a basic RPN scientific in their line-up priced to compete with the entry level Sharps and Casios, then RPN might have been more popular today.

#96

Wow - that looks very nice Walter! Thanks! ;)

Yes, a 30b design can work. We could swap out the >DEG/>RAD for GRAD mode and RAN# .

Since it is not programmable, it should not be hard to make the simple RPN calculator a solar-powered one. So instead of HP SmartCalc 300, which I think is really a clone of the Casio fx-300S(?) - they could have gone with something like a solar-powered 10C.

And yes, Phi and Phi^-1 are personal choices because I would like to have the calculator to have normal distribution functions.

#97

Here's a design:


#98

Sell it to me for $19.99 or less, or I'm not interested. It's just as easy to use my 15C / 15C LE.

#99

Get the shifted labels on the slanted key fronts and I'm with you ;-)

Quote:
Here's a design:



No matter how many times we reinvent the wheel it invariably
comes out round.

I'd expect at the present a 10c vs. 15c manufacturing materials
cost differential is likely US$1~2 at best. And most of that
would probably be the additional process step of laying down
the 15c's blue "g" key legends. IOW from the practical
perspective of today's commodity technology, a 15c arguably
is the entry-level RPN calculator.


Quote:
No matter how many times we reinvent the wheel it invariably comes out round.

Yep. That is why I posted that pic.
Quote:
a 15c arguably is the entry-level RPN calculator.

I completely agree.

To me the term "entry-level" means it must be the least expensive of the genre. IOW, unless the MSRP of the 15C is lowered below the 33s, it cannot be termed entry-level. That was the idea behind the 21, 31E and 10C. Each time HP found out that it wasn't worth the effort to dumb-down a model to artificially lower its price. I think most RPNers expect higher quality clicky keyboards that cost more, such that the best bet would be to mass produce the new 15C and package it similarly to the basic 12C, so the price could at least be halved to no more than $49.99.


Quote:
To me the term "entry-level" means it must be the least expensive of the genre. IOW, unless the MSRP of the 15C is lowered below the 33s, it cannot be termed entry-level.

The problem with the 15c is somewhat of a market quirk in that
it became a cult following. While arguably it has earned that
status, it does tend to push it into the collectible space
and distort its price. We'll see to what degree HP is actually
leveraging that distortion by what becomes of the 15c le
marketing strategy. Seems too early to tell at this point
what the actual product motivation may have been.

My point was rather, not much is needed to implement a voyager
given contemporary technology. And no significant overall cost
savings will result by sizing a SoC for minimal support of a
10c vs 15c.

Quote:
That was the idea behind the 21, 31E and 10C. Each time HP found out that it wasn't worth the effort to dumb-down a model to artificially lower its price. I think most RPNers expect higher quality clicky keyboards that cost more, such that the best bet would be to mass produce the new 15C and package it similarly to the basic 12C, so the price could at least be halved to no more than $49.99.

I don't pretend to be a marketing pundit, but there does appear
to be some fine tuned balance in such captive market, popular
appeal cases. Eg, the availability is regulated to slightly
under feed the market in order to maximize price, sales volume,
and sustained consumer demand. Mass producing the 15c and
selling at a less inflated end user price I suspect will jostle
the above marketing optimization.

Quote:
I think most RPNers expect higher quality clicky keyboards that cost more, ...

What is true is that most current RPNers expect ... . Sooner or later H-P has to understand that the current RPNers aren't the ones who will buy an entry level RPN machine so that they might as well be ignored when talking about one.

RPN is a legacy interface. It has no future.

exception: finance users.


Edited: 3 Nov 2011, 11:00 p.m.


So I guess all those students and young people who are buying the 33s and 35s are running them in algebraic mode ?


Both my kids are, and they have an RPN dad...who is always switching it on them, with no success.

Of course I prefer my 27s over the 15c and all the others, hands-down, for most things. Having been exclusively RPN forever, the discovery of the 17bii and later 27s was an epiphany. And I remembered having seen that 27s in the shop a long time ago, in the 90s, and turning my nose up at it then. What a fool I was! Live and learn--never too late to come to the Dark Side :-)

Edited: 4 Nov 2011, 12:01 a.m.


I own both the 27S as well as the 17bii as well as the 19bii. I simply have never been able to switch to algebraic mode and therefore I rarely, if ever, use the 27S. Now if that machine only had RPN <g>...

Maybe we on this forum are the odd ones out but I still feel that RPN is the better user interface. I *KNOW* what the machine is doing and I don't have to remember the differences between the different ways that algebraic can be implemented. Also I don't have to keep track of all those darn parens.

Cheers,

-Marwan


Quote:
Maybe we on this forum are the odd ones...

That's important to know. The majority of calculator users think algebraic is "normal".
Quote:
I *KNOW* what the machine is doing...

A misunderstanding that some RPN users seem to have. For someone brought up on algebraic, it is easier for me to "know" what it is doing compared to keeping up with what I have pushed onto the stack.
Quote:
... and I don't have to remember the differences between the different ways that algebraic can be implemented.

Don't forget there are different ways the stack is implemented on different RPN machines!
Quote:
Also I don't have to keep track of all those darn parens.

Another misconception! While this can be an issue on older algebraic machines, the newer ones display the parentheses so you can see them.

It's not the tool that makes the mistakes, it's always the one who uses it. But a tool that fits well in your hands or your mind is less prone to being used for making mistakes.

Quote:
Don't forget there are different ways the stack is implemented on different RPN machines!

Outside of RPL I don't see any real differences in the machines I use. All the RPN calculators I use today work identically other than the 20b and 30b which really aren't RPN and which I converted to WP34S firmware as soon as I could for that reason (among others). There is that CHS weirdness in the 12CP and some other early RPN machines but I don't tend to use those either. As for RPL, save the 20b and 30b implementations (which are a mix of RPN and RPL perhaps leaning to RPL a little), the differences hardly matter because like you point out for modern algebraics one can see exactly what is happening on the stack.


Quote:
A misunderstanding that some RPN users seem to have. For someone brought up on algebraic, it is easier for me to "know" what it is doing compared to keeping up with what I have pushed onto the stack.

Another misconception! While this can be an issue on older algebraic machines, the newer ones display the parentheses so you can see them.


I have never had a problem with keeping track of things on the stack. I started with algebraic calculators and yet from very early on (with RPN) I could just look at a problem and break it down into it's component pieces to attack it with RPN. Parens, on the other hand, would always screw me up. Back then there were no multi-line displays that showed parens or intermediate answers. I would find myself doing every problem twice to verify it and then a third time if the answers came back differently to figure out which of the two was correct. And I'll be darned if I didn't sometimes end up with a third answer. It was either that or write down all the intermediate answers or save them in memory until I could assimilate all the results. I never had this problem with RPN. Now it's true that modern algebraic machines don't generally have this problem due to larger displays and ability to show parens and intermediate results but now I find them impossible to use simply because my fingers are used to a particular order of input--it's what one is used to.

So, not a misconception at all since it is true for me (and I would suspect others). Instead I would say that we see the problem differently and so while you are more comfortable with algebraic I am far more comfortable with RPN. Neither viewpoint invalidates the other.

Marcus is right when he points out that the tool that works best for an individual is one s/he should use.

Cheers,

-Marwan


Quote:
Outside of RPL I don't see any real differences in the machines I use.

I include RPL machines as part of the RPN/postfix world.
Quote:
So, not a misconception at all since it is true for me (and I would suspect others). Instead I would say that we see the problem differently and so while you are more comfortable with algebraic I am far more comfortable with RPN. Neither viewpoint invalidates the other.

You are right, both viewpoints are valid. I used the term "misconception" because some RPN boosters keep saying the same thing about not being able to keep track of parentheses or not seeing intermediate results as if this were still true today. Meanwhile, algebraic calculators have changed and most of the calculating world has moved on, too.

My point being, that the advantages RPN once had compared to algebraics has mostly disappeared as algebraics (now with "textbook" entry) have advanced.

So RPN is not "dead", but just not relevant to most calculator users.


I actually like the semi-infix of old algebraics much more than the formula entry systems--unless I am doing a solving operation. That is what I love about the 27s and even the 33s--because you get both systems, each with their strengths for particular aspects.

I also do not consider RPL to be RPN. very closely related, but not the same, but of course I have noticed that some people who have only used rpl d get confused when using rpn and so I suppose it is a perfectly valid observation--because most rpl people assume rpn willbe the same. But we old timer rpn guys never make that mistake;-)


Quote:
I actually like the semi-infix of old algebraics much more than the formula entry systems--unless I am doing a solving operation. That is what I love about the 27s and even the 33s--because you get both systems, each with their strengths for particular aspects.

I agree, but it's because it's what I am used to.

Interesting thing about the 17b/27s, you can enter several functions two different ways in the Solver. For example, pressing the squared function key gets you SQ(, but you can also use the alpha menu and put in ^2. Similarly, you can hit the SIN key, or spell it out using alpha, either works!

The part infix, part postfix works well for me, and I like getting intermediate results, for instance every time you close a parenthesis or otherwise complete a partial result due to math hierarchy.

I really did not like the "true algebraic" way of the 35s, which uses infix for everything. SQ( ) is somewhat tolerable, but MILE( )?

I agree with you about the directness of RPN, and the potential screw-ups of varying implementations of algebraic.

Once a few years ago I started working on an article about the various algebraics but lost motivation--I didn't have anyone paying me to do it...

Unlike many algebraics, the 27s shows intermediate results as they develop. And it is the traditional semi-algebraic, so only the 2 number functions and the arithmetic operators are infix. Other than that, it is still rpn, and has a stack, too (I wish it had a swap function though!).

The one potential screwup in rpn is the stack depth. With singe line, you will from time to time run out...which means that aspect is not transparent--you have to keep track of it in the same way as keeping track of parenthesis on an old Ti...


Quote:
The one potential screwup in rpn is the stack depth. With singe line, you will from time to time run out...which means that aspect is not transparent--you have to keep track of it in the same way as keeping track of parenthesis on an old Ti...

May I recommend a WP 34S? Select SSIZE8 and this "problem" is solved :->

Quote:
RPN is a legacy interface. It has no future.

exception: finance users.


I disagree.

I am an engineer. if RPN is good enough for bean counters, it ought to be good for engineers too ;-)


And there are so many RPN calculator apps on Andriod, Apple, and Windows today - and most are more simple than the 15C.

I don't believe RPN is dead.

Quote:
I am an engineer. if RPN is good enough for bean counters, it ought to be good for engineers too ;-)

The real question is, do financial types use the 12c because it's RPN, or do they use RPN because that's what the 12c is?

i.e, the 12c has been for so long the de facto standard financial calculator, has its popularity simply become self-sustaining regardless of interface?


Quote:
The real question is, do financial types use the 12c because it's RPN, or do they use RPN because that's what the 12c is?

They are conditioned to use RPN now, they still don't understand it nor even make use of a 4-level stack. They are hooked, having used it for so many years, they can't switch to algebraic. Find me any 12CP user that sets it to algebraic mode, and I'll show you someone that has never used RPN.


Dave Hicks once told me that RPN was a good but slight upgrade from the adding machine logic that bean counters were accustomed to in the last generation of, well, adding machines. It also has the advantage of being consistently postfix and consistent in everything else. So: adding machine > hp80 (or 70) > hp22 > hp37,38.38c > hp12c for the old guys and first monkey suit, first calculator (12c) for today's crop of trump-a-bees.

I'm sympathetic with Bill. My first son turned his nose up at RPN. He's in the business world and uses TI business calcs. Second son is a college junior in Engineering, uses a TI-89 grapher, because that's the "standard" calculator for engineers at the school. Third son is also an engineering major, and is in love with the TI Inspire grapher. 4th son is in high school, has an HP-35s, but uses it only in algebraic mode. I can't win...

I'd love to see (and buy) a scientific calculator using the 10bII hardware. It doesn't have to be programmable, but should include everything the 20S & 21S had. RPN, of course, so maybe it would be called the 30S.

Fortunately for us, the new 10bII+ is repurposable so it's up to us, I guess. Any plans for a WP-30S...?


No plans by us. We're aiming higher.

The 42S will lose it position as the best RPN calculator if we have our way :)

- Pauli


Interesting - any comments on the hardware?


No ;-)

I had been pondering proposal of a repurposing of the 10bii+ as a simple RPN. It is light, relatively cheap, has a decent keyboard, and perhaps most importantly, a large, legible numeric display with big, bold decimal points and commas that can be easily seen. If we are talking simple, nothing would be more simple than one function per key, no shift key, no programming, no statistics. I tried to determine if I could fit enough functions on the 10bii+'s 40 keys, and came up with the following:

SIN	COS	TAN	LOG	LN

ASIN ACOS ATAN 10x ex

sqrt(x) yx 1/x % pi

Rv x<>y +/- EEX <-

LASTx 7 8 9 ÷

STO 4 5 6 x

RCL 1 2 3 -

ON/OFF 0 . ENTER +

The position of the ENTER key might be argued, or perhaps the need for Last x, but in general, the above is about as basic as can be had without deleting transcendental functions. (It actually compares pretty well with the original HP-35.) It would be nice to have a few more functions, like x2 or delta-% or xth root of y. Adding functions would require a shift key, which opens a lot of possibilities. But it also tends to lead to feature creep, and before you know it, you might as well go with wp34s. Trying to find the right place to stop, I present the layout below as a basic programmable RPN. It is loosely based on the 10C, but I dispensed with all statistics functions in favor of better programming. Programming could be artificially limited to a couple hundred steps. If you need more than that, time to graduate to wp34s (or maybe wp43s someday.)

ASIN	ACOS	ATAN	10x	ex
SIN COS TAN LOG LN

x2 y1/x HYP delta%
sqrt(x) yx 1/x % SHIFT

n! FIX SCI ENG ->P
STO RCL LAST x pi ->R

R­^ DEG RAD GRD Clx
Rv x<>y +/- EEX <-

GTO x=0? x<0? x>0? DSE
XEQ 7 8 9 ÷

LABEL x=y? x<y? x>y? ISG
P/R 4 5 6 x

PSE ->H ->H.MS INT FRAC
R/S 1 2 3 -

OFF ->DEG ->RAD LAST x CLEAR
ON/EXIT 0 . ENTER +


That looks good, Jeff.

Both your designs look very nice and consistent IMHO, though I clearly prefer a big ENTER for obvious reasons. Just in the second design I can't find RTN - where do you hide it? And CLEAR on shifted + looks a bit ... strange to me ;-)

Just my 20m€ as usual,

Walter


Thanks for the positive comments. I would of course prefer a large ENTER key, but one is not available on the 10bii+.

I might have missed including RTN. Maybe no subroutines are allowed. Yeah, that's the ticket. It is a simple RPN, so no subroutines allowed. (Or perhaps we could do without Pause.)

The CLEAR above the + was intended as a master clear that would not be used often. In program mode, it would clear all programs. In run mode, it would clear the stack and all registers.

Obviously you clearly see the importance of a dedicated LastX key - that's great. On the other hand even the most passionate RPN user probably will not insist on having two of them. ;-)

You say there will be no subroutines. So what is the use of the XEQ key? It could run individual routines starting at Label 0..9, just as earlier HPs did with their GSB key.

Finally, there are six tests, but none for X#0 and X#Y. These are essential since a combination of these and the others can easily replace the missing X>= and X<= tests. On the other hand, do you think such a basic device requires DSE and ISG?

Dieter


Quote:
Obviously you clearly see the importance of a dedicated LastX key - that's great. On the other hand even the most passionate RPN user probably will not insist on having two of them. ;-)

Ah, I see you found my Easter egg. Good job! Or perhaps I made an error.

With no subroutines, XEQ would be used just as you say. But I think I would actually include a RTN function and allow subroutines. As for DSE and ISG, pehaps a basic device needs only DSE.

Based on the above, here is a revised layout:

ASIN	ACOS	ATAN	10x	ex
SIN COS TAN LOG LN

x2 y1/x HYP delta%
sqrt(x) yx 1/x % SHIFT

n! FIX SCI ENG ->P
STO RCL LAST x pi ->R

R­^ DEG RAD GRD Clx
Rv x<>y +/- EEX <-

GTO x=0? x=/=0? x<0? x>0?
XEQ 7 8 9 ÷

LABEL x=y? x=/=y? x<y? x>y?
P/R 4 5 6 x

RTN ->H ->H.MS DSE INT
R/S 1 2 3 -

OFF ->DEG ->RAD CLEAR FRAC
ON/EXIT 0 . ENTER +

Quote:
I'd love to see (and buy) a scientific calculator using the 10bII hardware. It doesn't have to be programmable, but should include everything the 20S & 21S had. RPN, of course, so maybe it would be called the 30S.

Fortunately for us, the new 10bII+ is repurposable so it's up to us, I guess. Any plans for a WP-30S...?


Quote:
I'd love to see (and buy) a scientific calculator using the 10bII hardware. It doesn't have to be programmable, but should include everything the 20S & 21S had. RPN, of course, so maybe it would be called the 30S.

Fortunately for us, the new 10bII+ is repurposable so it's up to us, I guess. Any plans for a WP-30S...?



Maybe something like this:

This is an attempt to redo the design based on the 30b calculator (still no programming):

--------------------------------------

ES RPN 10-Solver

XROOT x^2 Phi^-1 >HMS >Polar FUNC
y^x Sqrt Phi >H >Rect APPS

ASIN ACOS ATAN 10^x e^x 1/x
SIN COS TAN LOG LN Pi

Last X R-Up FIX Spec Cl Regs
ENTER R-Down x<>y EEX < --

Sigma+ DEG RAD Mode x!
STO 7 8 9 ÷

Sigma- % %Chg Base RAN#
RCL 4 5 6 x

COMB PERM Clr St r/Sxy
Shift 1 2 3 -

OFF Mean SDev PDev L.R.
ON/C 0 . +/- +

--------------------------------------

FUNC: Enters a function f(x), use the registers as variables - up to 10 equations (0-9), 100 steps each

APPS = cycle through the steps
FUNC = when you are complete

APPS:
1. 2 x 2 or 3 x 3 Simulatenous Equations - prompted
2. Quadratic Equation - prompted
3. Cubic Equation - prompted
4. Evaluate Function X, variables are prompted
5. Root of Fucntion X for Register #
6. Integral of Function X in terms of Register #
7. Derivative of Function X in terms of Register #
8. Sum of Function (Sigma) of Function X in terms of Register #
9. Turn TVM Solver On/Off
0. Solver for TVM variable:

R0 = P/Y (not solvable)
R1 = N
R2 = I/YR%
R3 = PV
R4 = PMT
R5 = FV

Mode:
1. GRAD (DEG and RAD are on the keyboard)
2. ALL (FIX is on the keyboard)
3. ENG
4. SCI
5. Complex Roots Allowed = ON/OFF (Toggle)
6. Time Value of Money Mode = BGN/DUE (Toggle)
7. Rectangular/Polar Complex Mode (Toggle)

Spec (Special):
1. Complex Number Entry (i or angle)
2. ABS
3. ARG
4. INT
5. FRAC
6. REAL
7. IMAG
8. CONJ
9. DATE+
0. DAYS

Base:
1. DEC Mode
2. BIN Mode
3. OCT Mode
4. HEX Mode**
5. AND
6. OR
7. XOR
8. NOT
9. 1's Complement
0. 2's Complement

HEX Mode:

RCL RCL 0 = A
RCL RCL 1 = B
RCL RCL 2 = C
RCL RCL 3 = D
RCL RCL 4 = E
RCL RCL 5 = F


Phi = Normal Distribution Lower Tail
Phi^-1 = Inverse Normal Distribution Lower Tail

Added: Gradian mode, Combination, Permutation

Edited: 5 Nov 2011, 11:51 p.m. after one or more responses were posted


Looks a lot better than your first draft :-) Some remarks in random order:

  • I'd put FIX into Mode, too. Since the display mode previously set will be kept it looks like a waste of keyboard space else. Then, I'd put Mode on shifted x<>y instead.
  • x! should be placed in a line with COMB and PERM.
  • ClrSt is a bit isolated - I'd put it either on shifted / (next to the other clearing commands) or somewhere next to Sigma+ and Sigma-. Looks more logical IMHO.
  • Same applies for RAN# ...
  • You may deserve compliments for your design, but not for the two last items of Base. Oh, why can't the English learn to spell? ;-)
  • Regarding hexadecimal numeric input: Please note you can't use the functions in row 2 in hex mode, so you can easily put A ... F there for free.
  • What shall r/Sxy do?

Just my 20m€, as usual.

Walter


Quote:
Looks a lot better than your first draft :-) Some remarks in random order:
  • I'd put FIX into Mode, too. Since the display mode previously set will be kept it looks like a waste of keyboard space else. Then, I'd put Mode on shifted x<>y instead.
  • x! should be placed in a line with COMB and PERM.
  • ClrSt is a bit isolated - I'd put it either on shifted / (next to the other clearing commands) or somewhere next to Sigma+ and Sigma-. Looks more logical IMHO.
  • Same applies for RAN# ...
  • You may deserve compliments for your design, but not for the two last items of Base. Oh, why can't the English learn to spell? ;-)
  • Regarding hexadecimal numeric input: Please note you can't use the functions in row 2 in hex mode, so you can easily put A ... F there for free.
  • What shall r/Sxy do?

Just my 20m€, as usual.

Walter


My spelling should be corrected now. (bangs head against the table - LOL).

Here is Edition 2:

This is an attempt to redo the design based on the 30b calculator (still no programming - yet):

--------------------------------------

ES RPN 10-Solver (Edition 2)

XROOT x^2 Phi^-1 >HMS >Polar FUNC
y^x Sqrt Phi >H >Rect APPS

ASIN ACOS ATAN 10^x e^x 1/x
SIN COS TAN LOG LN Pi
(A) (B) (C) (D) (E) (F)

Last X R-Up Mode Spec Clr Reg
ENTER R-Down x<>y EEX < --

Sigma+ COMB PERM x! ClStat
STO 7 8 9 ÷

Sigma- % i/Ang Base RAN#
RCL 4 5 6 x

Sums Regr r PRED
Shift 1 2 3 -

OFF Mean SDev PDev a/b
ON/C 0 . +/- +

--------------------------------------

In menus, scroll with Roll Down and Roll Up. Use ENTER to choose an option.

FUNC: Enters a function f(x), use the registers as variables - up to 10 equations (0-9), 100 steps each

APPS = cycle through the steps
FUNC = when you are complete

APPS:
1. 2 x 2 or 3 x 3 Simultaneous Equations - prompted
2. Quadratic Equation - prompted
3. Cubic Equation - prompted
4. Evaluate Function X, variables are prompted
5. Root of Function X for Register #
6. Integral of Function X in terms of Register #
7. Derivative of Function X in terms of Register #
8. Sum of Function (Sigma) of Function X in terms of Register #
9. Turn TVM Solver On/Off
0. Solver for TVM variable:

R0 = P/Y (not solvable)
R1 = N
R2 = I/YR%
R3 = PV
R4 = PMT
R5 = FV

Mode:
1. DEG (moved into this menu)
2. RAD (moved into this menu)
3. GRAD
4. ALL
5. FIX
6. ENG
7. SCI
8. Fraction Mark: Decimal or Comma
9. Complex Display Mode: Rectangular or Polar

Base:
1. DEC Mode
2. BIN Mode
3. OCT Mode
4. HEX Mode
5. AND
6. OR
7. NOT
8. XOR
9. 1's Complement
0. 2's Complement

A-F has been moved to the second row as Walter suggested.

Regression:
1. Linear (y = a*x + b)
2. Power (y = b * x^a)
3. Logarithmic (y = a ln x + b)
4. Exponential (y = b * e^(a*x))
5. Inverse (y = a/x + b)

Sums: (Sigma(vars))
1. x
2. y
3. x^2
4. y^2
5. x*y
6. x^2*y
7. x^3
8. x^4

a/b returns a on the x stack, b on the y stack

PRED returns x-hat on the x stack, y-hat on the y stack

Spec (Special):
(I moved the complex number i/angle to the shifted funtion of the 5 key)
1. %CHG
2. ABS
3. ARG
4. REAL
5. IMAG
6. DATE+
7. DAYS

Too expensive to manufacture. Something more like the current HP-10s, but RPN.

Here's a better one. $12 USD at Amazon.

And another: $16 at calculatorsinc.com


$16 at calculatorsinc.com

Or another that is available in every Staples for $10.



Or this, which seems tiny:

They tout they're Direct Algebraic Logic (D.A.L.): http://sharp-world.com/products/calculators/sc_calculator/el-510r/index.html

Simple, inexpensive, non-programmable, introductory (to RPN), scientific RPN calc that can be a stepping stone to higher end calcs like the 15c.


Where is the RPN in these machines?


Quote:
Where is the RPN in these machines?

There isn't any RPN in those machines. That was the point. No non-programmable, entry level, value-priced RPN calc from HP. No stepping stone, (or gateway drug, judging by the denizens here) to higher end HP calcs.

It need not be a hp-10c. It need not be landscape mode. It need not have 15c style buttons. It just needs to be RPN and have a nice wide enter key on it. It needs to be priced (as others here suggested) at $20USD or under.

No high school or college student will ever consider a $99 15cLE (as another person here mistakenly suggested) an "entry level" scientific calculator.

Edited: 9 Nov 2011, 9:23 p.m. after one or more responses were posted


Quote:
No non-programmable, entry level, value-priced RPN calc from HP

That's true, and for a very good reason: there is no market for such a thing. TI owns the high school and college market. HP owns part of the financial market. HP would be foolish to make something they could not sell.

RPN is fun to play with for old fossils like us, but tomorrow's engineers and scientists will be ipad-equipped with all the calculating power they need. I'd say that is the principal reason HP is not making RPN scientific calculators anymore.


no, they'll skip the ipad entirely...

mathematica implants...

Quote:

That's true, and for a very good reason: there is no market for such a thing. TI owns the high school and college market. HP owns part of the financial market. HP would be foolish to make something they could not sell.

RPN is fun to play with for old fossils like us, but tomorrow's engineers and scientists will be ipad-equipped with all the calculating power they need. I'd say that is the principal reason HP is not making RPN scientific calculators anymore.


They don't know that. They screwed the pooch with the 10c. Look at the response of the 15cLE. How can they _not_ have an entry level RPN calc for high school students? One that is non-programmable and allowed on state tests. How do they expect to keep replenishing the "fossils"?

And you don't get to be an old RPN fossil if the barrier to RPN is set very high. And all of tomorrow's engineers will still have to take exams in settings where iPad, iPhones, Androids and other gadgets will not be permitted. Thus, the need for an RPN version of the Casio fx-260 or similar. Or, their only introduction to a basic scientific is a Casio, TI, or Sharp...


Edited: 9 Nov 2011, 9:21 p.m.


Quote:
How can they _not_ have an entry level RPN calc for high school students?

Well, for one thing, high school math teachers don't teach RPN because (a) they don't know RPN, (b) kids don't want or need to know RPN, and (c) I seriously doubt that RPN is in the math standards of any state, standards that dictate what will be taught in the classroom and tested on standardized tests.

Just as the HP-35 effectively made slide rules obsolete and the PC made typewriters obsolete, I think devices like the Ipad will ultimately make handheld calculators obsolete.

IBM doesn't make Selectric typewriters anymore. I don't know that anyone makes typewriters anymore. I think there will come a day when HP won't make calculators anymore as well. And I think the testing organizations will ultimately allow students to use Ipads during tests.

RPN is for hobbyists, just like programmers who still code with zeroes and ones. It's a very tiny market.

Quote:

They don't know that. They screwed the pooch with the 10c. Look at the response of the 15cLE. How can they _not_ have an entry level RPN calc for high school students? One that is non-programmable and allowed on state tests. How do they expect to keep replenishing the "fossils"?

And you don't get to be an old RPN fossil if the barrier to RPN is set very high. And all of tomorrow's engineers will still have to take exams in settings where iPad, iPhones, Androids and other gadgets will not be permitted. Thus, the need for an RPN version of the Casio fx-260 or similar. Or, their only introduction to a basic scientific is a Casio, TI, or Sharp...


I agree with you Nick.

If RPN is such a dead thing - then how come RPN calculator apps keep appearing on the market?

IHMO, HP missed the boat with the 10S, or the Smart Calc 300, both would have been the perfect opportunity to introduce an entry-level RPN calculator.

Edited: 11 Nov 2011, 12:42 p.m.

Quote:
No high school or college student..

That's probably true.

Quote:
..will ever consider a $99 15cLE (as another person here mistakenly suggested) an "entry level" scientific calculator.

That comment may not have been clear. It was not directed
at HP's 15c le productization but rather the functionality
of a 15c relative to the cost of contemporary silicon required
to implement it. IOW stripping resources down to minimally
satisfy a less capable device is unlikely to produce a
justifiable cost savings.

Perhaps a moot point as I suspect RPN devices vanish along
with those who still recall its long since dwindled market
justification.

Quote:
It needs to be priced (as others here suggested) at $20USD or under.

Casio programmable graphing calculator for under £10 (<$17 at current exchange rates).

Note of warning: I got two of these and both had some liquid around the batteries (which were totally depleted - they do date from the early '90s). I don't know what the liquid was, but there was no corrosion and after dismantling and a thorough cleanup all was well.

The Casio fx-260 isn't a bad utility calc for the glove box
and I've picked up several in recent years at MalWart for
about US$7. Actually at the risk of near blasphemy in this
forum I'd admit Casio calculators IME have held up surprisingly
well for an econo caclulator. In the general use scientific
market I'd imagine they are the leader in features*reliability/price.

OTOH most Sharp and every TI I've had the misfortune to own have
consistently and reliably failed primarily due to lcd zebras or
heat seal deterioration and of course TI's infamous keeeeeepppppaadd
debouncing algorithms.

BTW I've never seen a TI-34 before but I wouldn't want to be
seen in public with anything so hideous.


The HP-6S solar holds up well in the glove box as well. It's nearly identical to the Casio fx-260 in function.


Quote:
The HP-6S solar holds up well in the glove box as well.

The HP 6S is a pretty good item to have in the glove box, because it has a hard plastic rim along the sides that makes it a serviceable windshield ice or mud scraper. Other than that, IMHO the 6S is without contest the poorest excuse for a scientific calculator ever made by (or for) anyone. Even though it uses solar and battery power there's no power OFF key, the keys are abominable in feel, and my 2001 batch CN10015 started loosing display segments six years ago just sitting in a drawer. But it is kind of pretty (after I wash the mud off). :-)

Quote:
It's nearly identical to the Casio fx-260 in function.

The fx-260 is a nice low-end $10 unit. I've still got every Casio I ever purchased new. One from 1978, the credit-card scientific fx-48, was carried in my pockets at work for years. All still work as well as when new, keys respond just as when new, and all LCD segments are still clear a third of a century after manufacture. Even HP's 1979 HP-41C series can't claim similar long-endurance display quality...the HP's 48S and 48G series couldn't claim that even when new!

The current Casio fx-115ES (a.k.a. 991ES) is one of the most amazingly capable devices in my 35-year collection. Yet it costs only $13 to $18 retail in the USA. There's a very slightly improved 991ES Plus, but I've never seen it for sale here. It's the only non-RPN calculator that is worth the adjustment effort to use. The 115ES is my take-everywhere calculator. I've got one at my desk, one in the truck, and even one in my day-hike backpack. Really. :-)


Never know when you might need to compute the great circle bearing from Mt Mitchell to Mount Washington for an impromptu mountaintop to mountaintop QSO.

Quote:


The fx-260 is a nice low-end $10 unit. I've still got every Casio I ever purchased new. One from 1978, the credit-card scientific fx-48, was carried in my pockets at work for years. All still work as well as when new, keys respond just as when new, and all LCD segments are still clear a third of a century after manufacture. Even HP's 1979 HP-41C series can't claim similar long-endurance display quality...the HP's 48S and 48G series couldn't claim that even when new!



You are right about the displays and keys of the older Casios (heresy I know). I have an FX-350 which I was given when I started high school around 1981 and the keys and display are still fine. It's very light and thin and not overly endowed with functions but I did get about 10 years out of the first battery. In contrast all the recent Casios I've used have been utterly poor quality. I went through two FX-991ESs in three years at work due to key problems and odd errors and started to take a 33S of my own in with me as the key bounce on them was truly infuriating. I did eventually manage to get my my employer to replace the Casios with a 35S which is a definite improvement. I think the FX-991s only cost about £19 which kind of says it all as regard to the quality you can expect though. I suspect the old FX-350 cost substantially more.

I do think a basic feature set RPN calculator is needed as an introductory (or harsh environment) machine. I also think it should be decent quality though and reliable. Twenty Dollars sounds too cheap for that and I think quality can help sell even a basic device if it's marketed properly. What it needs to be is small and tough. It needs an easily read display (an illumination button would be a great selling point) and enough basic functionality to make it useful for simple engineering or scientific calculations. It also needs to be just cheap enough so you won't worry unduly about taking it where it might get dirty, damaged or stolen. For me that price point sits at about £25 (c.$40) though I'm sure others will think differently.


In the states, the 33s costs $39.95


I think a $15-$20 RPN calcualtor would be good - the price would be in the line with most entry-level scientific calculators. Even the size of the fx-260 would work.

No comment on the TI -34.


Edited: 11 Nov 2011, 12:47 p.m.


I just bought an HP 10bII+ for $29.99, and am extremely impressed with the overall quality of the product, keyboard and display. If HP could use it as a platform for a basic non-programmable RPN scientific calculator, and lower the price to $19.99, I'd call it a sure winner. I'm not sure how profitable it would be at that price point, though.

But really, what't the point? Even the old 65 was no more difficult to use for simple stuff, than the 21. Back then, there really was a price difference based on hardware differences.

Today, the hardware is so overpowered to begin with that it is foolish to underdesign the capabilities, since you can have all that extra power without detracting from the simple stuff.

Or in other words, it ain't any cheaper anyway.


Quote:
But really, what't the point? Even the old 65 was no more difficult to use for simple stuff, than the 21. Back then, there really was a price difference based on hardware differences.

Today, the hardware is so overpowered to begin with that it is foolish to underdesign the capabilities, since you can have all that extra power without detracting from the simple stuff.

Or in other words, it ain't any cheaper anyway.


It's more about perception these days (more functions = more value = more money) and manufacturers exploit this to try and maximise sales and profit. As I said in an earlier post, if HP had kept a cheaper basic RPN scientific in their line-up to compete with entry level Casios and Sharps, the RPN might have been more popular today.

Quote:
It's more about perception these days (more functions = more value = more money) and manufacturers exploit this to try and maximise sales and profit. As I said in an earlier post, if HP had kept a cheaper basic RPN scientific in their line-up to compete with entry level Casios and Sharps, the RPN might have been more popular today.

The obvious difference in the hardware between models is the display. (Ironically, seven-segment displays have the best contrast and look the clearest.) Though I wonder how much the cost difference is between a 12 digit 7-segment, 12x 5x7 dot matrix and two line 16x144 dot matrix?

The 10bII+ is half the selling price of the 30B ... how much of that is the display or is it just functionality: it does more so it must cost more?

Another reason calculators with larger function sets cost more: you have to write a larger manual. It's not the cost of thicker printed manuals (they are all PDF now) it's the labour for writing the documentation.

I agree with you last comment: a non-programmable RPN calc aimed at college students who had to do just the basic math+stats courses (and not the engineering, maths, physics majors) would have spread the gospel.

Kevin

Ahh, but I am not clear enough.
They problem is that they *can't* go cheaper. The 33s is already as cheap as they can go...lowering the performance would still cost $40, instaed of the $15 for the Casio.


Put it in the hardware of the current HP-10s, at $15 who cares if you have to buy a new one every 2 years?

Edit: or a 300s if you want a touch fancier.

Edited: 4 Nov 2011, 12:32 p.m.


is that hardware that bad?


Don't know, I don't have a 10s, but was just postulating :-)

The 300s keyboard has mushy keys. The 10bii+ keys are nice and clicky.

Quote:
As I said in an earlier post, if HP had kept a cheaper basic RPN scientific in their line-up to compete with entry level Casios and Sharps, the RPN might have been more popular today.

It isn't so much a matter of the calculators in the lineup as it is the calculator availability in the mass market. I was in both a Target and a Wal-Mart this past weekend. There were too many TI models to count, several Casios and some Sharps. Not a single HP. How can that lead to popularity of HP or of RPN?

Quote:

It isn't so much a matter of the calculators in the lineup as it is the calculator availability in the mass market. I was in both a Target and a Wal-Mart this past weekend. There were too many TI models to count, several Casios and some Sharps. Not a single HP. How can that lead to popularity of HP or of RPN?


I never see HP at Target. Staples only has the HP 12C. Office Depot carries the HP business line (10BII+, 12C, 30b).

Edited: 5 Nov 2011, 2:50 p.m.


You have to go to an electronics store like Frys to find them. They sell them for MSRP, same as the HP online store.

It all boils down to that different customers are prepared to pay a different amount of money for a given (same or similar) product. Those who wants a lot and are not cost sensitive will buy high end. Then there are those that want to pay less. You want to sell to them too (as long as you are making decent money), without affecting the price and sales of the high end product. Making a cheaper alternative with less capabilities is the answer to this.

Hardware cost is the same today, but I think the manufacturing cost for the original 10C compared to a 15C were similar back then. HP even invested the money in another code base variant (10C) in order to sell to other customers.

For some reason, the plot failed with the 10C. If it was because the 10C sold too little to make any point, or if it affected the sales of the 11C in a negative way, I do not know.


It is interesting to note how manufacturers have competed by cramming more features into the calculators, as opposed to making them cheaper. I'd bet that only a small percentage of that advanced capability is used by the average buyer. Case in point - Even though I have multiple high-end calculators, on a daily basis I typically use no more than the functionality available on my HP-45. My daily driver is a 35s, and my "high-end" calculations are usually basic algebra, trig, and logs. Only a few handy programs (closer to macros, actually) are programmed in either my 35s or 50g. So I see the logic in making an "Entry Level" calculator.


If I have to do any sums, for any purpose, I go as fast as I can to a spreadsheet or failing having a machine on, to a 48G, using a list. I have to be dragged kicking and screaming to do sums on *any* calculator (the 48G isn't a calculator, is it;-)

The 32s, the 33s, any non-I/O machine is great for the trigs,logs, and very short ad-hoc programs when you are on the run and don't need to document with a spreadsheet or mathcad. Or perhaps you are working by hand step by step and validating a spreadsheet. That might be my most important use of RPN. I even skip the 27s if I can in this and grab RPN, probably for the very same reasons Marwan mentioned.

Edited: 4 Nov 2011, 12:23 p.m.

I posit that if failed for exactly my hypothesis previously mentioned: that the savings, which were minimal, weren't enough to justify buying one. The market proved this. They are the hardest to find. As I remember it, they came out at $80 when the 11c was $100. And I bet they had almost no profit margin. If I remember correctly, my 11c cost $120 in 1982. Man, was that a fantastic machine at that time! I think I must have had the same sort of joy the iphone users have now :-D

Edited: 4 Nov 2011, 12:31 p.m.

Quote:
For some reason, the plot failed with the 10C. If it was because the 10C sold too little to make any point, or if it affected the sales of the 11C in a negative way, I do not know.

I think HP created too much choice, or the price difference was too small. It would have been better to stick with the 11C, maybe at a slightly cheaper price they would have sold more than the 10C & 11C together. Of course retrospect is easy, but HP seemed to have learnt the lesson and with the Pioneers released 2 RPN versions, the 32S (followed by the 32SII) and the 42S. Both have quite a following.

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