The Museum of HP Calculators

HP Forum Archive 18

[ Return to Index | Top of Index ]

The number of keys...
Message #1 Posted by DaveJ on 18 Nov 2007, 1:25 a.m.

With all the recent talk on calculator design and key layout etc, I began to wonder (again) why someone hasn't produced a scientific calculator with a LOT of dedicated keys? There is no major practical design reason for it in most cases, so the limitation must lie elsewhere with the designers or marketing.

Most calcs have a lot of wasted front panel space that could be put to use with an extra 2 or 3 lines of keys. Shave an extra mm or two here and there and you could even fit another 4 lines of keys. With 6 across on a basic portrait calc that's another 18 or 24 keys. Imagine a full set of dedicated BaseN keys and few if any shift functions, I think that would be REALLY NICE!

Maybe one day that might be the next advance (or even "fad") in calculator design?

Dave.

      
Re: The number of keys...
Message #2 Posted by Thomas Radtke on 18 Nov 2007, 10:16 a.m.,
in response to message #1 by DaveJ

Have you ever seen this baby?

I personally love calcs w/ many keys allthough I don't own one of these oversized commodores. The C-4190SR, of which I'm a proud owner, is already quite impressive and very useful.

            
Re: The number of keys...
Message #3 Posted by Maximilian Hohmann on 18 Nov 2007, 11:37 a.m.,
in response to message #2 by Thomas Radtke

Hello!

Quote:
I personally love calcs w/ many keys allthough I don't own one of these oversized commodores.

Me too :-) (Both: I love them and I have a Commodore N-60 navigation calculator). There is nothing wrong with keys, I much prefer them over menus and "Alpha" modes. One of my favourite calculators, the Ti Voyage 200, has over 80 keys, including a full typewriter keyboard.

Greetings, Max

                  
Re: The number of keys...
Message #4 Posted by Thomas Radtke on 20 Nov 2007, 5:56 a.m.,
in response to message #3 by Maximilian Hohmann

OT

Quote:
(Both: I love them and I have a Commodore N-60 navigation calculator).
I was never able to get one at a reasonable price. However, I once managed to get a mint Heathkit OC-1401 for about 20 EUR. It was like christmas when it arrived :-).

/OT

                        
Re: The number of keys... OT
Message #5 Posted by Maximilian Hohmann on 22 Nov 2007, 7:21 a.m.,
in response to message #4 by Thomas Radtke

Hello!

Quote:
I was never able to get one at a reasonable price. However, I once managed to get a mint Heathkit OC-1401 for about 20 EUR.

With me, it is exactly the other way round ... found the N60 quite cheap, but haven't been able to get the OC-1401 for less than the price of a good second hand car.

Quote:
It was like christmas when it arrived :-).

Yes, I know this feeling :-) This week, I had two christmasses already because I got a Tamaya NC2 and an Navtronic 16, both luminous-display navigation calculators that were missing from my collection. And none of them more expensive than 25 EUR.

Greetings, Max

            
Re: The number of keys...
Message #6 Posted by DaveJ on 18 Nov 2007, 3:36 p.m.,
in response to message #2 by Thomas Radtke

Yeah, that is a step in the right direction, but more buttons could be fitted if they were the more modern smaller rectangular size. And I'm, not sure what some of those keys do - programming keys? I'd like something this Casio FX-992S I happen to have in front of me now:

I'm picturing something like that with say an extra 3 three rows in the same size case.

The extra rows would get say all the basic BaseN keys (10 keys), X-Y, 10^X, e^x, STO, Min, R-P, P-R etc.

Dave.

                  
Re: The number of keys...
Message #7 Posted by Thomas Radtke on 19 Nov 2007, 5:45 a.m.,
in response to message #6 by DaveJ

Quote:
And I'm, not sure what some of those keys do - programming keys?
No, these extra-wide Commodores weren't programmable.
                        
Re: The number of keys...
Message #8 Posted by DaveJ on 19 Nov 2007, 6:30 a.m.,
in response to message #7 by Thomas Radtke

Quote:

No, these extra-wide Commodores weren't programmable.


Ok, so what do the keys like E, k, and P do? Many keys are hard to make out, anyone got a better photo?

Dave.

                              
Re: The number of keys...
Message #9 Posted by Walter B on 19 Nov 2007, 7:25 a.m.,
in response to message #8 by DaveJ

Looks like the upper left quarter deals with statistics and probability.

                                    
Re: The number of keys...
Message #10 Posted by Thomas Radtke on 20 Nov 2007, 5:51 a.m.,
in response to message #9 by Walter B

The upper half of the S61 is apparently dedicated to statistics.

Here's a better image:

      
Re: The number of keys...
Message #11 Posted by Don Shepherd on 18 Nov 2007, 10:42 a.m.,
in response to message #1 by DaveJ

If you like keys.

            
Re: The number of keys...
Message #12 Posted by sylvandb on 18 Nov 2007, 3:10 p.m.,
in response to message #11 by Don Shepherd

Quote:
If you like keys.

Those don't look like keys... They look like little rubber buttons!

sdb

            
Re: The number of keys...
Message #13 Posted by DaveJ on 18 Nov 2007, 3:25 p.m.,
in response to message #11 by Don Shepherd

Alpha keyboards don't count. I'm talking about useful dedicated function keys. That TI is useless, it doesn't even have a primary LOG key, QSQRT key, or ENG key etc - absolutely useless!

Dave.

                  
Re: The number of keys...
Message #14 Posted by Maximilian Hohmann on 18 Nov 2007, 3:33 p.m.,
in response to message #13 by DaveJ

Hello!

Quote:
That TI is useless, it doesn't even have a primary LOG key, QSQRT key, or ENG key etc - absolutely useless!

And what is that, then (I hope Joerg Woerner dosen't mind when I link to his site, but since it was him who promoted this machine on this forum a few weeks back...)?

http://www.datamath.org/Graphing/Images/TI-Nspire_K_ZOOM.jpg

Greetings, Max

NB: I do not know if this second keyboard comes with every nSpire or if it has to be pruchased separately.

                        
Re: The number of keys...
Message #15 Posted by DaveJ on 18 Nov 2007, 3:40 p.m.,
in response to message #14 by Maximilian Hohmann

Quote:
Hello!

And what is that, then (I hope Joerg Woerner dosen't mind when I link to his site, but since it was him who promoted this machine on this forum a few weeks back...)?

http://www.datamath.org/Graphing/Images/TI-Nspire_K_ZOOM.jpg


Again, absolutely useless for me. That is a typical programming/grapics calc key layout, I talking a basic scientific layout. Again, that layout doesn't even have an ENG or SQRT key for starters.

Dave.

                              
Re: The number of keys...
Message #16 Posted by Maximilian Hohmann on 18 Nov 2007, 4:31 p.m.,
in response to message #15 by DaveJ

Hello!

Quote:
Again, that layout doesn't even have an ENG or SQRT key for starters.

ENG is something you have to setup through a menu in this machine (same as with the much praised HP-42S!). And Sqrt is shifted with x^2 as the unshifted function, most HPs have it the other way round (but there are exceptions too, for example the original HP-45). Probably something one can easily adapt to.

But of course, a "simple" scientific calculator with all essential functions on separate keys is most efficient to use.

Greetings, Max

                                    
Re: The number of keys...
Message #17 Posted by DaveJ on 18 Nov 2007, 4:48 p.m.,
in response to message #16 by Maximilian Hohmann

Quote:
ENG is something you have to setup through a menu in this machine (same as with the much praised HP-42S!). And Sqrt is shifted with x^2 as the unshifted function, most HPs have it the other way round (but there are exceptions too, for example the original HP-45). Probably something one can easily adapt to.

But of course, a "simple" scientific calculator with all essential functions on separate keys is most efficient to use.


That's what I'm talking about, just a simple scientific with lots of dedicated keys, so no shift function is needed for most things.

X^2 and SQRT are such primary functions for me, it's crazy to have them shifted on a scientific calc in my opinion.

BTW, the ENG key I'm talking about is the Casio type ENG key, not the HP ENG "display mode" (which I don't like). And of course, if you have an ENG key, you should have an inverse ENG key as well.

I wish my photoshop skills ere good enough to whip up one of these "dream" concept calcs!

Dave.

                                          
Re: The number of keys...
Message #18 Posted by Walter B on 18 Nov 2007, 6:05 p.m.,
in response to message #17 by DaveJ

Quote:
BTW, the ENG key I'm talking about is the Casio type ENG key, not the HP ENG "display mode" (which I don't like). And of course, if you have an ENG key, you should have an inverse ENG key as well.
If anything is completely useless and a true waste of keyboard space, it's this kind of ENG. Anybody being able to write "scientific" shall be able to do this operation by heart.
Quote:
I wish my photoshop skills ere good enough to whip up one of these "dream" concept calcs!
He he, this is no photoshop, it's honest work :)
                                                
The usefulness of an ENG button...
Message #19 Posted by DaveJ on 18 Nov 2007, 7:25 p.m.,
in response to message #18 by Walter B

Quote:
If anything is completely useless and a true waste of keyboard space, it's this kind of ENG. Anybody being able to write "scientific" shall be able to do this operation by heart.

And easily make a mistake doing this trivial but mental (and hence subject to error) manipulation.

I love being able to get a result in scientific notation and (if needed) hit the ENG button to get an unambiguous display of the engineering value. It is not useless to me (and many others), as an electronics designer I use it everyday and find it hard to live without.

A good calculator should take the burden away from me, not put additional burden on me to get a (albeit simple) mental manipulation of decimal places correct. If I want a result in engineering display, I should be able to press a button to do that.

This is why HP calcs have the ENG display mode, and others like the Casios have an ENG button to perform this operation when needed. Some Casios also have an ENG display mode as well as the button, the best of both worlds.

Dave.

Edited: 18 Nov 2007, 7:25 p.m.

                                                      
Re: The usefulness of an ENG button...
Message #20 Posted by Walter B on 19 Nov 2007, 1:19 a.m.,
in response to message #19 by DaveJ

FWIW, I was not talking about the ENG display mode (which has its merits for sure), but the operations ENG-> and <-ENG.

                                                            
Re: The usefulness of an ENG button...
Message #21 Posted by DaveJ on 19 Nov 2007, 1:30 a.m.,
in response to message #20 by Walter B

Quote:
FWIW, I was not talking about the ENG display mode (which has its merits for sure), but the operations ENG-> and <-ENG.

So was I.

It puzzles me though how you can see the merits in having an ENG display, but see absolutely zero merit (for other people, even if it's worthless to you personally) in having an ENG button which does *exactly* the same thing, except you are able to effectively turn on ENG display mode at will when needed by pressing the button.

I can name several keys on every calculator I have that I deem to be personally worthless to me, but I can at least understand how they might be useful to others who do different things with their calculator than I do.

Dave.

                                                                  
Re: The usefulness of an ENG button...
Message #22 Posted by Walter B on 19 Nov 2007, 1:45 a.m.,
in response to message #21 by DaveJ

Dave, you wrote first

Quote:
BTW, the ENG key I'm talking about is the Casio type ENG key, not the HP ENG "display mode" (which I don't like).
and now
Quote:
It puzzles me though how you can see the merits in having an ENG display, but see absolutely zero merit ... in having an ENG button which does *exactly* the same thing, except you are able to effectively turn on ENG display mode at will when needed by pressing the button.
This puzzles me.

For sake of clarity, I see no use in an operation just telling the user 45 Ohm are equal to 45 thousand Milliohm or 0.045 Kiloohm. Anybody not knowing this shall return his/her engineering degree.

                                                                        
Re: The usefulness of an ENG button...
Message #23 Posted by DaveJ on 19 Nov 2007, 2:13 a.m.,
in response to message #22 by Walter B

Quote:
This puzzles me.

For sake of clarity, I see no use in an operation just telling the user 45 Ohm are equal to 45 thousand Milliohm or 0.045 Kiloohm. Anybody not knowing this shall return his/her engineering degree.


You have obviously never used the Casio version of ENG in practice then. It's most useful feature is converting scientific notation into engineering notation, *exactly* like the ENG "mode" on HP's. So if you get a result like 1.23x10-8 you hit the ENG button and you get 12.3x10-9 Yes, it has a secondary function of then being able to "move up and down" engineering units with subsequent key presses, if that's what you really want to do. But I agree there is little value in that.

The reason I don't like the HP ENG "mode" is because I prefer to work in normal scientific notation most of the time and then be able to simply hit a button to convert to ENG when needed. For example, with the HP ENG mode ON if my result is 0.123 then the HP will display that as 123x10-3 every time. I find that annoying, as most of the time I would simply want it to display that as 0.123. To fix that I have to chop and change between modes all the time, and changing modes is a real pain in the butt.

The Casio ENG button gives me the flexibility to display what I want when I want with a single key press.

Has that clarified things?

Dave.

                                                                              
Re: The usefulness of an ENG button...
Message #24 Posted by marais on 19 Nov 2007, 3:50 a.m.,
in response to message #23 by DaveJ

I second that. My Casio FX-602 has this fabulous ENG button, my HP calcs lack it. In the engineer's life (and not only EE) this button is a really convenient feature, and I rely on it as often as I rely on other basic scientific functions, much more than on programming capabilities these days. I recently came to appreciate this function for radiation shielding calculations, where units like GBq (Giga Bequerel) and mSv (milli Sievert) are common. Being able to pad the final result to the required unity with the ENG button is extremely useful.

                                                                              
Re: The usefulness of an ENG button...
Message #25 Posted by Walter B on 19 Nov 2007, 4:23 a.m.,
in response to message #23 by DaveJ

Thanks for your explanation. I learned you want to switch immediately from any display format to ENG. I happen to have a Casio fx-991ES in my drawer (hate it for its fluffy keys and more) and I tried the ENG button. Fine. However, I didn't find an "inverse ENG" to return thereafter to the format displayed before. Do you know where it's hidden? Else, this would be a one way road, disturbing my sense of symmetry.

                                                                                    
Re: The usefulness of an ENG button...
Message #26 Posted by DaveJ on 19 Nov 2007, 6:16 a.m.,
in response to message #25 by Walter B

Quote:
Thanks for your explanation. I learned you want to switch immediately from any display format to ENG.

Yep, should have explained that clearer early on.

Quote:
I happen to have a Casio fx-991ES in my drawer (hate it for its fluffy keys and more) and I tried the ENG button. Fine. However, I didn't find an "inverse ENG" to return thereafter to the format displayed before. Do you know where it's hidden? Else, this would be a one way road, disturbing my sense of symmetry.

Sorry, there is no proper way back, it's a one-way ticket! Actually, there are several ways to get back, but they are a kludge. You can press =, do a store/recall to memory, hit 1/x or X-Y twice, or some other operation which brings the result back to the screen again. X-Y twice is probably the pick of the bunch if it's primary key, otherwise 1/X.

I can appreciate the lack of symmetry being disturbing. It's the same reason why I desire an INV ENG key even though I basically don't use, it gives me a sense of symmetry also. So when I'm bored I can sit there shifting my ENG result up and back down again just for fun!

Dave.

                                                                                    
Re: The usefulness of an ENG button...
Message #27 Posted by Meenzer on 19 Nov 2007, 6:42 a.m.,
in response to message #25 by Walter B

I don't have the fx-991ES, so I can't tell you about its features. My older fx-3500P however has an ENG and an INV-ENG key. But the INV-ENG doesn't return you to the format displayed before ENG was used. Instead that would be done by simply pressing the = key.

What ENG does is:

"0.02" ENG "20 -03" ENG "20000 -06" and so on

"0.02" INV-ENG "0.02 00" INV-ENG "0.00002 03" and so on.

If you press = after either of the above steps the display shows the original "0.02".

EDIT: My understanding from the online manual of the fx-991ES is that it works just in the same way. INV-ENG is the arrow pointing to the left on top of the ENG key.

Edited: 19 Nov 2007, 7:00 a.m.

                                                                        
Re: The usefulness of an ENG button...
Message #28 Posted by Meenzer on 19 Nov 2007, 3:24 a.m.,
in response to message #22 by Walter B

Quote:
For sake of clarity, I see no use in an operation just telling the user 45 Ohm are equal to 45 thousand Milliohm or 0.045 Kiloohm. Anybody not knowing this shall return his/her engineering degree.

You might want to rethink this...

I surely know PI to 30 decimal places, but I still use the PI-key on the calculator just because it's convenient and allways right - no fear of changed decimal places or whatever.

I also know many of the sine and cosine values of common angles by heart, but would always punch the key instead.

I can do most of my everyday +-*/ math in my head (and do so), but I use the calculator most of the time to double check.

And so on...

                                                                              
Re: The usefulness of an ENG button...
Message #29 Posted by Walter B on 19 Nov 2007, 4:11 a.m.,
in response to message #28 by Meenzer

Meenzer, I was talking about technical people. Lawyers don't compete ;)

Edited: 19 Nov 2007, 4:24 a.m.

                                                                                    
Re: The usefulness of an ENG button...
Message #30 Posted by Meenzer on 19 Nov 2007, 4:31 a.m.,
in response to message #29 by Walter B

Quote:
I see no use in an operation just telling the user 45 Ohm are equal to 45 thousand Milliohm or 0.045 Kiloohm. Anybody not knowing this shall return his/her engineering degree.

Quote:
Meenzer, I was talking about technical people. Lawyers don't compete ;)


No need for a personal offense.

I have an engineering degree but don't work as an engineer. And I'm most certainly not giving back my degree because you say so.

Edited: 19 Nov 2007, 4:32 a.m.

                                                                                          
Re: The usefulness of an ENG button...
Message #31 Posted by Walter B on 19 Nov 2007, 5:42 a.m.,
in response to message #30 by Meenzer

Sorry, Meenzer, no offense intended. Did you notice the emoticon?

After all, I wonder why tech people need ENG-> or <-ENG. Apparently I must accept it, but I don't understand. Well, perhaps I don't have to understand.

                                                                                                
Re: The usefulness of an ENG button...
Message #32 Posted by DaveJ on 19 Nov 2007, 6:26 a.m.,
in response to message #31 by Walter B

Quote:
After all, I wonder why tech people need ENG-> or <-ENG. Apparently I must accept it, but I don't understand. Well, perhaps I don't have to understand.

We don't need it (and many "nicety" features like this), but when they are there they are nice features to be able to use. Same with the HP ENG mode, FIX modes, SCI modes etc.

We could survive if our calc always said 0.000000123, but it's nicer when it says 1.23x10-7, and sometimes even nicer again when it says 123x10-9

What other "nice" features can people not do without?

Dave.

                        
Re: The number of keys...
Message #33 Posted by Don Shepherd on 18 Nov 2007, 5:34 p.m.,
in response to message #14 by Maximilian Hohmann

The keypad shown is the TI-84+ keypad. The regular NSpire handheld comes with its normal keypad (my picture) and the TI-84+ keypad. They snap in and out. The NSpire CAS handheld comes with only the regular NSpire keypad and does not offer snap in and out.

The NSpires are meant for students, not engineers.

Students don't complain if they have to press a shift key to get a square root

      
Re: The number of keys...
Message #34 Posted by thyl on 20 Nov 2007, 2:08 a.m.,
in response to message #1 by DaveJ

If you omit a display, you can place even more keys on the front.

Yeah, promoting my idea of a dedicated calculator keyboard in connection with a smartphone as a display/CPU again....

            
Re: The number of keys...
Message #35 Posted by Garth Wilson on 20 Nov 2007, 3:57 a.m.,
in response to message #34 by thyl

Quote:
If you omit a display, you can place even more keys on the front.
Or put the display on the back.

At my last place of work, orders from the top were so strong to cut costs on a particular computer, that we used to joke about eliminating the I/O since it accounted for much of the cost. And with no I/O, performance requirements could be dramatically relaxed because the customer would be hard-pressed to find a bug or other shortcoming.

Actually, it was great how the HP-41 solved the problem of the keyboard size getting out of hand, and how to deal with functions that had not been thought of yet when the calc came out. With the user keyboard, I don't often spell out a function in alpha.

            
Re: The number of keys...
Message #36 Posted by DaveJ on 20 Nov 2007, 7:09 p.m.,
in response to message #34 by thyl

Quote:
If you omit a display, you can place even more keys on the front.

Yeah, promoting my idea of a dedicated calculator keyboard in connection with a smartphone as a display/CPU again....


It would have to be wireless of course.

Then, if you just want to add two numbers quickly (which is what most calcs do most of the time), you have to fumble with two different machines just to do that, making it too fiddly to use.

The only way that idea would take off would be to have a small screen built in for your basic calcs, to make it usable in it's own right, and then wireless access to a bigger screen/smartphone when that is required.

Dave.

      
Re: The number of keys...
Message #37 Posted by Chuck on 20 Nov 2007, 7:08 p.m.,
in response to message #1 by DaveJ

My HP28 had a good many keys on it, and I found my way around it just fine. The keys on the left could have even had more functionality.

            
Re: The number of keys...
Message #38 Posted by Garth Wilson on 20 Nov 2007, 7:35 p.m.,
in response to message #37 by Chuck

How was the 28's reliability? I always wondered because of the joint that would have to flex so many times. How did they make the connections? Was it a flex circuit (like conductors printed on a sheet of plastic), or stranded wires that would twist slightly down the length of the hinges? I suppose they used a serial interface to reduce the number of conductors that would be necessary.

                  
Re: The number of keys...
Message #39 Posted by Paul Dale on 20 Nov 2007, 8:02 p.m.,
in response to message #38 by Garth Wilson

I never had a problem with my 28s even after a lot of use. The battery compartment door on the other hand is a disaster.

I still feel that the successors to the 28s compromised on the keyboard usability significantly.

- Pauli

                  
Re: The number of keys...
Message #40 Posted by sylvandb on 20 Nov 2007, 10:14 p.m.,
in response to message #38 by Garth Wilson

Quote:
How was the 28's reliability? I always wondered because of the joint that would have to flex so many times. How did they make the connections? Was it a flex circuit (like conductors printed on a sheet of plastic), or stranded wires that would twist slightly down the length of the hinges?

Very reliable. I worried about that joint as well. Somewhere I read it was designed for 1,000,000 cycles closed to all the way open. It uses wires that twist a bit.

sdb

                        
Re: The number of keys...
Message #41 Posted by Randy on 20 Nov 2007, 11:58 p.m.,
in response to message #40 by sylvandb

The only wire in a clamshell model is used for the battery springs :^O

The keyboard connections to the left side used two double sided flex circuits for a total of 12 conductors. The width of the pair is only three traces wide allowing it to fit within the hinge. The left side keyboard is 6x6 allowing direct scanning with the 12 conductors.

Another interesting part of the design was that both keyboards where actually all one piece while the center section shaped in a serpentine U did the flexing. A very interesting multilayer project and decent keyboard. The snap was provided by a formed plastic sheet that was laid on top of the switch elements. I can post a photo if anybody is interested.

Similar flex fabrication technology was originally used for the 41 battery/port connector block and later on the first versions of the Voyager models.

The reliability of the series was good overall but the battery door was legendary and the typical ultimate failure mode is when the right side case halves begin to separate due to fractured heat stakes. Then you use them as a paperweight.

Edited: 21 Nov 2007, 12:14 a.m.

                              
Re: The number of keys...
Message #42 Posted by Paul Dale on 21 Nov 2007, 4:27 p.m.,
in response to message #41 by Randy

What would the possibility of refitting a paper-weighted 28 series with a new processor be like. That and a keyboard overlay could make for something rather nice...

- Pauli

                                    
That and a keyboard overlay could make for something rather nice...
Message #43 Posted by Randy on 21 Nov 2007, 8:30 p.m.,
in response to message #42 by Paul Dale

and you would still have the battery door issues. It's a dead platform. Nothing to see here, move along.

                                          
Re: That and a keyboard overlay could make for something rather nice...
Message #44 Posted by Paul Dale on 21 Nov 2007, 8:53 p.m.,
in response to message #43 by Randy

I think that the silly battery compartment could be worked around. Some glue and a dremel :-)

Still, the device is dead and gone...

- Pauli

                                    
Re: The number of keys...
Message #45 Posted by DaveJ on 21 Nov 2007, 8:46 p.m.,
in response to message #42 by Paul Dale

Quote:
What would the possibility of refitting a paper-weighted 28 series with a new processor be like. That and a keyboard overlay could make for something rather nice...

Now you've got me curious! Anyone got any internal photos of the 28S?

Guess I could crack my one open and take a look... Just how do you get a 28S apart anyway?, I've never tried.

Dave.

                                          
Re: The number of keys...
Message #46 Posted by Paul Dale on 21 Nov 2007, 8:51 p.m.,
in response to message #45 by DaveJ

There are instruction for opening a 28 series machine here: adding IO to a HP28.

I think I'll leave mine intact - such as it is.

- Pauli

                                          
Re: The number of keys...
Message #47 Posted by Randy on 21 Nov 2007, 9:19 p.m.,
in response to message #45 by DaveJ

Quote:
Guess I could crack my one open and take a look... Just how do you get a 28S apart anyway?

Peel off the labels surrounding the keyboards and the label over the battery area. Drill the heads off the gazillion heat stakes you find underneath. Shake well, parts will go everywhere. Good luck reassembling.

Quote:
Anyone got any internal photos of the 28S?

It's a 19Bii but once you remove the keyboard overlays, you wouldn't know the difference.

PS: About twelve of the heat stakes had already failed and fell out when I peeled back the keyboard overlays.

All the bits:

Closer view of the keyboard:

Edited: 21 Nov 2007, 9:27 p.m.

                                                
DIY calc
Message #48 Posted by DaveJ on 21 Nov 2007, 10:35 p.m.,
in response to message #47 by Randy

Hmm, ok, looks a bit messy!

I still think that a very good way to get a DIY calc platform is to retrofit a commercial product.

As we have all seen and talked about in recent months, the two main stumbling blocks to a DIY calc are the LCD and the housing/keys. Yet, a DIY calc design should all be about features, usability, and tweaking the software and key layout etc.

In that case it kinda makes sense to retrofit an existing calc to utilise the case, (some of the) keys, and possibly the custom LCD.

Perhaps the DIY calc enthusiasts should discuss the merits and possibilities of doing that with say a 35S, or a 17BII+, or something else?

Imagine say the shiny new 35S with a set of new top keys, overlay, and a new PCB and software that does your bidding...

Dave.

                                                      
Re: DIY calc
Message #49 Posted by Walter B on 22 Nov 2007, 3:18 a.m.,
in response to message #48 by DaveJ

Good morning, Dave,

please look at this post in June. Just make the LCD a bit smaller, turned out to be too optimistic then :)

Best regards,

Walter

                                                      
Re: DIY calc
Message #50 Posted by Ren on 26 Nov 2007, 11:52 a.m.,
in response to message #48 by DaveJ

Quote:
Hmm, ok, looks a bit messy! [...] Dave.

Yes, but a picture is worth a kiloword! The photo shows how the keyboard flex connector distributes the rotational forces over a greater distance than would be accomplished by "conventional" (i.e. cheap) shortest distance connection. Ingenious...

Ren

dona nobis pacem

                                                
Re: DIY calc
Message #51 Posted by Paul Brogger on 26 Nov 2007, 12:40 p.m.,
in response to message #47 by Randy

I've got a 28s in similar shape. (It simply fell apart after repeated flexing in my son's overloaded high school backpack.)

One of my (many!) unrealized project plans is to drill out all the heat stakes front & back, and rebuild the calculator with tiny hex bolts and cap nuts. (Stainless for the 28s, brass for the 19bII ;-)

I think a clamshell with an industrial-strength look about it -- dozens of hex-head fasteners arrayed about its surfaces -- would be pretty cool. However, such a treatment would do nothing about the infamous battery compartment cover. (Bummer!)

The ONLY thing I've actually played with recently is trying to put a 41c keyboard on a TI-83+SE. (I looked into shoe-horning the 83+'s PCB and LCD into a 41C case -- probably with the card reader's case attached -- but the main and LCD PCBs seem just a bit too wide, and I'm reluctant to start filing them down. 8-0 )

If anyone knows that the 84+'s PCB is significantly smaller, I'd like to hear about it! It does appear that its LCD is integrated with the keyboard/processor PCB, rather than attached via a ribbon cable. (That feature of the 83+ and 89 seems to offer some options for creative display placement.)

The TI 83+ (now 84+) and 89 do offer PC development environments and emulators, albeit ones intended for development of "applications" rather than variations on the OS. (I'm not at all sure of the significance or malleability of those limitations.)

Anyway, lots of talk, not much action. I just recently put the disassembled parts away in a box -- the 83+'s LCD board separated from the main PCB; its keys and everything else loose and begging for application . . .

(BTW, I swapped the original 83+SE guts and keys into a straight 83+ case, and the result is an especially handsome hybrid -- big, bold legends on the key faces, and none of the translucent glitter of its original case.)

Edited: 26 Nov 2007, 5:06 p.m.

            
Re: The number of keys...
Message #52 Posted by DaveJ on 20 Nov 2007, 8:40 p.m.,
in response to message #37 by Chuck

Yes, I have a 28S too. Shame it had practically no dedicated scientific keys.

Dave.

      
I still prefer...(was: The number of keys...)
Message #53 Posted by Vieira, Luiz C. (Brazil) on 22 Nov 2007, 4:30 a.m.,
in response to message #1 by DaveJ

... the elegant and clearer HP41 keyboard. The necessary number of keys, fits in your palm (the first palmtop computer????) and all not seen, additional features can be found with either [CAT] 3, [CAT] 2 or other suitable, custom DIRectory functions. No need to remind function names to spell them after [XEQ][ALPHA], and the keyboard is not cluttered with so too many collored labels... I also like the MENU features in the HP42S, but this is another religious cruzade, though...

My 2... 1, perhaps.

Luiz (Brazil)


[ Return to Index | Top of Index ]

Go back to the main exhibit hall