Form factor for calculators



#2

In another thread, Mike Morrow wrote:

Quote:
The HP 42S is not the answer to everything, I suspect.

But...after 21 years, nothing in its form factor has appeared that is an advance, an improvement, or even a simple equal in capability.

One has to resort to larger, heavier, RPL machines. :-(

At least those are inexpensive!


Looking at HP's current lineup of scientific calculators there is very little variety in the form factor. What form factor do you like? Would you buy multiple calculators in different form factors for different needs?

One of my favorites was the 29C because you could hold it in one hand and reach all the buttons with your thumb. The hinged design of the 28C looks like it was very handy too.


#3

Woodstocks (21,22,25,27,29C) were very good in form factor, however today's tren would be a slimmer body, to be carried in a shirt pocket (not in Mr. Hewlett legendary pocket, I mean).

HP41: very good too; Voyagers and Pioneers almost optimal.

Today models: 17B II silver (almost equal to HP42 and other Pioneers). HP 48/49/50 and HP35S are too large.


#4

I concur. Just want to add the 20b to today's models being handy. Could be even handier without the double shell on its back.

#5

Quote:
The hinged design of the 28C looks like it was very handy too.

Spoken like somebody who's never used a 28C! ;)

In fairness, it's pretty nice when you've got a big, flat surface to work on, but anything else becomes a huge pain. Handheld operation is awkward at best.

And don't get me started on broken battery doors...


#6

I've had a 28S for 20 years. It is fine to use as a handheld with the second keyboard folded all the back. All keys were not quite accessible using one handed thumb method though (but I daresay that neither are the 48/49/50). I did make sure that I'd pre-programmed all the formulas that I would need to avoid having to use the second keyboard though.

Indeed the battery door was probably the most stupid design to come out of HP. I have had to repair mine with an extra strip over the door. I still enjoy using it.


#7

Yes, software-wise, the 28C and 28S are very good. Having loads of keys greatly speeds typing, though I find the form factor is sub-optimal for anything but a desk or table. I like 'em, but I'd rather just use my 48SX or 48GX. Wouldn't mind getting ahold of a 19BII with the improved battery door, though.


#8

I wonder if one could swap out the insides, not minding the darker plastic of the 19BII (obviously I'm not in the finance sector and don't care much for financial calcs). I remember reading a historic HPCC article about using a drill to open the 28C - a bit destructive.


#9

Ah, but that is the bueaty of an Hp 19Bii. It has trig functions and units conversions. And it is both RPN and Algebraic selectable. Many Hp19Bii owners gripe about this calculator no longer being available and that the Hp17Bii being a poor substitute.


For my own preference, I like the Voyager format in size but accept the Hp42s due to its superiority over the Hp 15c in most areas.

My dream calculator would be to take the existing NEW Hp 17Bii and stuff the Hp50G rom into it minus the Graphing abilities. Power it with three button cells and provide an external power jack, USB port and SD card slot. Let the market and Hackers develop the rest. The power jack would drive the external periphials. Hp has the case and would only need to modify I/O points to stuff this technology into an existing line. I would pay $150, probably more for such a POCKET CALCULATOR!!!!

Notice """HP"""", that I suggest a pocket calculator ie TW and Cryille!!!!!

Hp's present Hp17Bii is an existing platform that is the closest match to what I would want. Admittedly, if Hp releases an Hp15c for sake of vintiage appeal, I will indeed buy one also, if it is at a similar price to the existing Hp12c line (ie don't rob me for being an engineer, HP).


#10

Way back in February, I had such a 17bii-based proposal posted here. To save search time, here it is again.

HTH


#11

I like that, but let me guess not RPL. Or does (could) it have a choice (like the current RPN/ALG)?


#12

It's designed to work for RPN and ALG like the 17bii and the 35s. Not for RPL, however, because I think that's overkill. The 44s is meant to be a small keystroke programmable scientific without graphics. It's a member of a set of 4 drafts I designed based on a Voyager, a Pioneer, the 17bii, and the 35s.

BTW, I looked up the old files and found these drafts are older than I wrote: they were published in two articles in DATAFILE V27, including a complete menu system for the command set of the 44s.

Ceterum censeo: HP, launch a 43s (please check the files and you'll know why).

Walter

#13

Quote:
My dream calculator would be to take the existing NEW Hp 17Bii and stuff the Hp50G rom into it minus the Graphing abilities.

I've had the same in mind: graphics is best done on a PC. A powerful compact RPL calc would be ideal in my mind.


I looked at the financial calc details: 17BII+ lots of program memory, basic math (LN EXP etc) but no trig functions. 20B has trig/hyp trig functions but no program memory. Nothing that has the "best of both"!!

#14

OK, but what needs to be done is "only software", as my late boss used to say. Plus a proper layout, but that's no witchcraft d8-)

Edited for this P.S.: The presence of an interface allowing the input of this "software" is a necessary requirement, of course. That puts the 20b and 12c+ on the list.

Edited: 13 Nov 2009, 6:39 a.m.

#15

Quote:


Spoken like somebody who's never used a 28C! ;)

In fairness, it's pretty nice when you've got a big, flat surface to work on, but anything else becomes a huge pain. Handheld operation is awkward at best.

And don't get me started on broken battery doors...


It's true! I've never used one. Thanks for pointing out the pitfalls of this design.
#16

A credit card scientific would be my ideal form factor (RPN of course). Something I could carry unobtrusively anyway.

- Pauli


#17

Quote:
A credit card scientific would be my ideal form factor (RPN of course). Something I could carry unobtrusively anyway.

Yep, that's my holy grail calc format too.

Of course, I could always just design my own if I needed to.

Such a thing would be much easier than the Mk2 uWatch, that's for sure.

A thin alloy box (smaller than a Voyager) design with a PCB touch panel keypad, and maybe changeable key overlays, running from a couple of CR2032's would be pretty easy. No one else would probably want one though, so it wouldn't exactly set the world on fire.

Dave.


#18

I'd want one if it was thin enough....

- Pauli

#19

Take a Voyager. Any Voyager. Put it in your left shirt pocket with the near bulletproof metal back facing out and the medallion up.

To use, simply reach in with your right hand, thumb on the medallion, index finger on the back and slide out. In parallel raise your left hand to greet your number crunching companion. When they meet, place the Voyager on your curved left index and middle fingers, and then with purpose press the ON button with your left thumb. Proceed to thumb-board your way through your most challenging problems. When complete, reverse the process until your Voyager rests against your left breast.

That my friends is the perfect form-factor. Now if Dave will make me a credit-card size version of the 15C, well then I may find a new traveling companion.


#20

Doesn't work for me. I pretty much never wear a shirt with a pocket :-)

- Pauli


#21

You know, I was thinking about that the other day. None of my calculators have a hole to use with a lanyard. If they did, then I could wear it around my neck. Just in case.

I do not think my wife would let me out of the house with such a rig. May be an idea to get out of holiday shopping that I must explore.

I guess holsters are still a possibility for the shirt pocket free crowd. I remember my first HHC, Richard had a 50g strapped to his waste like a sixshooter. I chuckled and hoped the programming challenge would be quick-draw style. I am fairly certain that Darth Vader had at least 2 RPNs on his utility belt--he had no shirt pocket either.


#22

Quote:
I guess holsters are still a possibility for the shirt pocket free crowd. I remember my first HHC, Richard had a 50g strapped to his waste like a sixshooter. I chuckled and hoped the programming challenge would be quick-draw style. I am fairly certain that Darth Vader had at least 2 RPNs on his utility belt--he had no shirt pocket either.

That's similar to the way we carried our slide rules in the olden days. The only thing that identified us as engineering students more than that was carrying a drawing board and T-square.
#23

Quote:
Now if Dave will make me a credit-card size version of the 15C, well then I may find a new traveling companion.

After some quick thought, how does 5mm thick sound?


That's for an all alloy or stainless steel case, your choice of W x D.

Sounds easily do-able on first thought, unless feature creep takes over.

Could be made thinner, but I'm factoring in use of standard CR2032 batteries.

Dave.


#24

Count me in for a programmable scientific RPN calc in credit card format. 5mm thickness is fine. 15C emulation would be great !


#25

Count me in as well.

#26

Quote:
After some quick thought, how does 5mm thick sound?

That would be the upper limit I suspect and thinner would be better. My ideal would be to fit into my wallet beside or in place of a credit card or three.


Quote:
Could be made thinner, but I'm factoring in use of standard CR2032 batteries.

Unless the battery isn't directly adding to the thickness, using CR2016 batteries would pull it down to 3.4mm thick which would be a lot better.

Would solar be an option instead of a battery? Yeah, I know feature creep which must be avoided especially in a small volume like this.


- Pauli


#27

Quote:
Unless the battery isn't directly adding to the thickness, using CR2016 batteries would pull it down to 3.4mm thick which would be a lot better.

Would solar be an option instead of a battery? Yeah, I know feature creep which must be avoided especially in a small volume like this.


I've already got what might be a suitable LCD, but it's only 8 digits. It is however the 14 segment type with apostrophe. 52mm x 22m x 3mm. That makes credit card DxW doable.

That would result in say a 4.8mm thick calc, but it would have a big (7mm high) readable 14 segment display and suck almost no juice.
Two displays could be joined for a landscape calc, with a bit of a gap in the middle.

Biggest power consumer would be the the touch panel solution.

Solar power chews up panel space that could otherwise have buttons.

I've got a tiny sub 2mm thick graphic LCD on hand, but the contrast is really lousy. 7-segment high contrast is the go IMO.

Dave.

Edited: 12 Nov 2009, 8:18 a.m.


#28

Hi.

I own such a thin one - Sharp's EL586 water-proof, dual-powered 10digits, scientific calculator.

Its geometry is 141.5x73.8x3.5[mm] (5.6x2.9x0.14 [inch]).


I have used the calculator putting it on the moving-arm of the drafter, in the late 80's.

I wish it had been an RPN programmable.

Regards, Lyuka

#29

I don't think I've seen a credit card calculator in portrait form factor (i.e. they are always landscape).

24 "buttons" seems fairly standard and I'm sure would be sufficient. The 4-banger designs of couple of years back were all based on 20 buttons and they got pretty complex (as in scientific and programmable). The buttons are often laid out in a 6x4 grid (but not always e.g. the Citizen W11S).

Most (all) include a small solar cell beside the display as well.

Thicknesses range from 2mm up and the suggested 4.8mm should be okay.


- Pauli


#30

Quote:
I don't think I've seen a credit card calculator in portrait form factor (i.e. they are always landscape).

24 "buttons" seems fairly standard and I'm sure would be sufficient. The 4-banger designs of couple of years back were all based on 20 buttons and they got pretty complex (as in scientific and programmable). The buttons are often laid out in a 6x4 grid (but not always e.g. the Citizen W11S).

Most (all) include a small solar cell beside the display as well.

Thicknesses range from 2mm up and the suggested 4.8mm should be okay.


I think I've come up with a way to make this thing cheaply, using the off-the-shelf LCD I've got, and 4.1mm thick or maybe less.

So picture a credit card size (WxH) calc (actually slightly wider for a portrait calc), just over 4mm thick, with a high contrast 8 digit 14segment display running from a single CR2016 battery replaceable as a "slot in" on the bottom end, along with a standard 0.1" header connector for programming on the bottom edge as well.

No need for an expensive case, it will be an entire sandwich FR4 fiberglass design, with your chose of color on the bottom.

The only major choice is whether to go for a stick-on membrane keypad which would increase the height a bit, possibly afford some extra protection for the glass LCD, but does not add to the power consumption. Or a touch panel interface that does not increase the thickness, but does chew the battery more.

It's actually looking quite easy and cheap, there must be a catch...

Dave.


#31

Quote:
So picture a credit card size (WxH) calc (actually slightly wider for a portrait calc), just over 4mm thick, with a high contrast 8 digit 14segment display running from a single CR2016 battery replaceable as a "slot in" on the bottom end, along with a standard 0.1" header connector for programming on the bottom edge as well.

Sounds ideal., wider is probably livable, taller wouldn't be.
Why the portrait fixation? I've never seen a credit card calculator that wasn't landscape...


Quote:
The only major choice is whether to go for a stick-on membrane keypad which would increase the height a bit, possibly afford some extra protection for the glass LCD, but does not add to the power consumption. Or a touch panel interface that does not increase the thickness, but does chew the battery more.

How much thicker? The feel would be slightly better with a membrane. To avoid the power consumption of the keyboard, would it be possible to have a separate off/on switch?


- Pauli


#32

Quote:
Sounds ideal., wider is probably livable, taller wouldn't be. Why the portrait fixation? I've never seen a credit card calculator that wasn't landscape...

No real reason, it's just that the display I have is almost the exact width of a credit card.

I'll need to try a few actual PCB variations to see what works best.

Quote:
How much thicker? The feel would be slightly better with a membrane. To avoid the power consumption of the keyboard, would it be possible to have a separate off/on switch?

Not much. Sample membranes I have are around the 0.5mm mark or so, depends on the dome size really.

Separate on-off switch should be easy. In fact my current design thinking makes it easy to add buttons all around the outside edge!

Dave.


#33

Quote:
No real reason, it's just that the display I have is almost the exact width of a credit card.

All the credit card calculators I've ever seen have a small display in the top right, solar panel in the top left and keys below. The display you mentioned would suite this style well. Is the display backlit?


Quote:
In fact my current design thinking makes it easy to add buttons all around the outside edge!

Please don't do that :-)
A couple of buttons or slide switches would be more than adequate.


I did try to see how a SafeWord token could be repurposed into a calculator ( see the Gold 3000 on https://www.snapgear.com/index.cfm?skey=1106 ). Fourteen buttons, eight character 14 segment display and a not very capable processor.


- Pauli


#34

Quote:
All the credit card calculators I've ever seen have a small display in the top right, solar panel in the top left and keys below. The display you mentioned would suite this style well. Is the display backlit?

Here is the LCD

No backlight, although a side LED could be added.

Although if you do solar power then there won't be enough light to light the LED when you need it :->

I'm actually liking the solar power thing, I've found a suitable solar cell, although at present it would be the most expensive part of the calc. Plenty of juice in a 22mm x 7mm solar cell

After playing with the screen on a credit card, it's obvious the landscape format is the best. with as you say solar cell in the top right.

No need for side switches if solar powered. Perhaps a super cap to maintain charge when the light dims.

Total thickness could be as small as 4mm now.

This is getting rather exciting, I shall christen the idea, surprise surprise, the uCalc!

Dave.


#35

I agree no LED if solar powered. I'm assuming that a solar cell will replace the battery completely.

A super cap sounds like a good idea to cover the odd shadowing etc. Some non-volatile memory ought to be possible too -- quite a few PICs have EEPROM on board. Will there be enough juice to program this?

A slide switch might still be useful -- program/run mode or deg/rad/grad. Not vital of course.

Can the keyboard be squeezed out to 28 keys (4 rows of 7)? There ought to be space and having more than 26 keys is good for letters.

How about the uCCC for a name? Or uCCCalc?

- Pauli


#36

Quote:
I agree no LED if solar powered. I'm assuming that a solar cell will replace the battery completely.

Yes, no battery.

Quote:
A super cap sounds like a good idea to cover the odd shadowing etc. Some non-volatile memory ought to be possible too -- quite a few PICs have EEPROM on board. Will there be enough juice to program this?

Yep, should be plenty.
Or external EEPROM like the uWatch maybe, oodles of PCB space available.

Quote:
A slide switch might still be useful -- program/run mode or deg/rad/grad. Not vital of course.

Can the keyboard be squeezed out to 28 keys (4 rows of 7)? There ought to be space and having more than 26 keys is good for letters.


The cheapest touch chip is the 24key one, the 32key one is triple the price.

Will have to see how the PCB layout works. Recommended key spacing is 8mm

Membrane might ultimately be the cheapest and simplest option here, although requires some NRE, but not required for getting a full prototype running though. In that case, as many keys as will sensibly fit, and the user could more easily change it to alter the key layout and look.

Quote:
How about the uCCC for a name? Or uCCCalc?

Nice try, but I like uCalc!

Dave.


#37

Damn, now I'm feature creeping...

I can make it thinner by 1mm by using the same LCD as my uWatch MK2, but without the backlight assembly.

That's a 128x32 graphic display about 35mm x 10mm window.

Much lower contrast than the 7 segment display, and 5 times the cost, but you get full dot matrix flexibility and 1mm thinner as compensation.

I could in theory now make this 3mm thick (+membrane), but a membrane keypad would probably need a thicker front panel, so say 3.3mm. Although you could pot it for extra rigidity and maintain 3mm perhaps.

Dave.


#38

I much prefer the look of non-dot matrix displays and the higher contrast. Still, thinner is better.

Is contrast a big issue for a solar powered calculator? How much light will be required to power the device? WIll that offset the lower contrast?


- Pauli

#39

If we're allowed to feature creep would a micro SDHC slot fit along one edge?
No need for much EEPROM then.

That or a USB port to interface externally.

- Pauli

#40

Dave:

Quote:
Membrane might ultimately be the cheapest and simplest option here, although requires some NRE, but not required for getting a full prototype running though.

How about this switch ? It is 3.7mm square and only 0.35mm thick. A little expensive -- about US$0.16 each.

You would have to add your own overlay adding a little thickness.

-- Rich


#41

Quote:
How about this switch ? It is 3.7mm square and only 0.35mm thick. A little expensive -- about US$0.16 each.

Yeah, the problem with these sorts of switches is the cost adds up.

Considering you need a custom overlay anyway, you might as well pay a bit more and get a tactile dome overlay and have the contacts on the PCB. I need actually get a quote for that option.

Dave.

#42

Quote:
How about the uCCC for a name? Or uCCCalc?

Voyager II?
#43

Quote:
All the credit card calculators I've ever seen have a small display in the top right, solar panel in the top left and keys below.
Well, some have the display and the solar panel the opposite way:


#44

Bummer, I got the display and solar panel backwards. Solar panel top right, display top left is what I meant.

This one sure has a lot of buttons on it.

- Pauli

#45

I'd be happy to have something just like that fx-98 pictured above in RPN. Casio made a slightly smaller and thinner credit card scientific in 1978, the fx-48. It was not solar powered, and although it has only 22 keys (compared to the fx-98's 38 keys), it provides most of the functions found on the later fx-98.

In 1985, Radio Shack sold the EC-4009, a slightly enhanced version of the fx-98 that included permutaion and combination functions above the parenthesis keys.

I still have my EC-4009 and my fx-48, both still working. I wish I had a few of the EC-4009 units that I gave away as gifts 25 years ago.

Credit card sized calculators are the only hand-held calculators whose usability is *not* significantly degraded by having a landscape layout. In fact, I believe that it's quite helpful.

#46

Dave,

It sounds like you're onto something easier and potentially more attractive to calculator enthusiasts than a uWatch II. Why don't you EEVBlog your ruminations and trials of this. It might be interesting to follow your progress and I'll bet that you get some good feedback as well.

-Katie


#47

Quote:
It sounds like you're onto something easier and potentially more attractive to calculator enthusiasts than a uWatch II.

Easier, yes, more attractive, I doubt it. Based on the exposure of my previous uWatch, a sexier looking Mk2 would no doubt make front page of every geek blog on the planet. Can't see the same thing happening for a credit card calc though. Even if it would probably be the worlds first credit card size scientific/programmable/RPN/open source calc.

But, oh... this has just given me a possible idea for the design of the MK2 uWatch! guess that'll make it iteration #50 or so...

Quote:
Why don't you EEVBlog your ruminations and trials of this. It might be interesting to follow your progress and I'll bet that you get some good feedback as well.

I thought about that way back, but I go through so many thought processes and iterations that it would turn into an endless blog, and people would probably come to conclusion that I'm nuts :->

I can picture the complaints now "20 bloody blog episodes on this damn watch and you still haven't done the first prototype!"

Dave.


#48

In a way, some of us are "burned childs" of the OpenRPN project way back: a lot of blogging, but no tangible results after many months. So I can understand why people prefer developments on their own now, and want to show up no earlier than a prototype is present.


#49

Quote:
In a way, some of us are "burned childs" of the OpenRPN project way back: a lot of blogging, but no tangible results after many months. So I can understand why people prefer developments on their own now, and want to show up no earlier than a prototype is present.

I don't blame them.

That is why no one gave my uWatch a second thought until I actually produced a real prototype, and then people went ballistic.

The same is happening to the uWatch MK2, no prototype yet, so little interest. Not easy or cheap to prototype such a thing though, so it's harder to get off the ground.

The uCalc on the other hand would be cheaper and easier to prototype, so hopefully will come off much sooner than the uWatch.
I've actually got all the parts except the solar cell, so all I need is some PCBs and a working prototype that looks like the real thing is complete.

Dave.

#50

Quote:
more attractive to calculator enthusiasts than a uWatch II

I meant "attractive" as in "attracting more buyers/users". A small credit card style RPN calculator would be a lot more usable (IMHO) than wearing one on your wrist. Besides, some of us have wrists that your uWatch have no chance of fitting on.

-Katie


#51

Wear it on your ankle then :-)
Or upper arm.


- Pauli

#52

If a square root is scientific enough:

Regards,

Joerg

#53

Quote:
My ideal would be to fit into my wallet beside or in place of a credit card or three.

All you need to do is make a programmable magnetic stripe that your new calc will program for whatever credit card you want to use at any given instant (and have this new calc be thin enough that it will fit through the swipe machine at the checkout stand).

Seriously, though, in this day and age of everything programmable and portable, I am surprised that nobody has invented the universal credit card replacement - the only thing that the checkout stand needs is the info in the magnetic strip. There should be any number of ways to read your choice of MasterCard, VISA, Discover, AmEx info into the cash register when you check out - maybe a mini USB connector from the store that plugs into your "credit card calc" [the calc would even keep a running track of your balance(s)]. Then you could get rid of all of that plastic in your wallet and replace it with something more useful.

In fact, years ago, I had a dongle not much bigger than a pencil eraser that I could use at Mobil gas stations for charging a fillup - it was "connected" to my AmEx account. Nowadays, you'd use bluetooth, I guess.

With a sharp enough graphics display, I suppose you could display a barcode that the store checkout laser reader would scan for your account info.


#54

Interesting idea but where would you put the golden credit card company logo on? :)

In fact, that's the reasoning behind the chips in modern bank cards: They contain multiple "applications" and are, as a benefit, much more secure because everything that goes into and out of the chip is encrypted. A useful CC sized device would be able to talk to such a chip and return the stored info about your recent transactions.

Edited: 16 Nov 2009, 7:36 a.m.

#55

I too carry a calc in my shirt pocket every day and use it many times daily. A 60 page spiral memo-pad, pens, glasses and an Aurora N1000, which is a hinged case calc (clamshell). Form factor.....<1/2 inches thick. It has to use RPN, which the FN1000 does. The battery compartment cover is secured by a small Phillips screw, therefore none of the 19B case problems. The clamshell is the selling point to me, as I work in a less than pristine environment. If I worked in an office environment, a 17BII or a 10B would be the calc I would carry.
Clamshell, RPN, fits in shirt pocket and a keypad similar to 17B11, which unfortunately the FN1000 does not have.....would be perfect for me.

don

#56

Quote:
One of my favorites was the 29C because you could hold it in one hand and reach all the buttons with your thumb.

Thank you for posting that. I thought I was the only one using their calculator 1-handed. Now if only my HP 29C's red LED display didn't seem tinier to my older eyes then it did when i bought my 29C new, from my local Eaton's Business Machines' counter, 33 years ago.

...bt


#57

That's exactly why iPhone + 42s (or i41CX+) is the best combination for me. I use it with left hand/thumb, it works great!

The size/shape of an iPhone looks like a great form factor for calculators. Fits in a jeans' pocket easily too.

Edited: 12 Nov 2009, 12:42 a.m.

#58

I'm almost certainly a minority here but I've often wondered whether it would be possible to get Casio to OEM its databank calculator watches with the minor firmware change to make them scientific and RPN. If so there would be a modern equivalent to the (in)famous HP-01 but without the tremendous development costs as it would be essentially an existing off-the-shelf product save for that bit of customization (the firmware plus key overlay and manual/packaging).

Too bad HP hasn't done that. They *have* done so for decades with other products - Epson and Canon printers sold as HP with custom firmware, for example.

Just dreaming...

Jim Horn (my HP-01 is too limited and my Casio scientific watch lost its "8" key)


#59

Quote:
I'm almost certainly a minority here but I've often wondered whether it would be possible to get Casio to OEM its databank calculator watches with the minor firmware change to make them scientific and RPN. If so there would be a modern equivalent to the (in)famous HP-01 but without the tremendous development costs as it would be essentially an existing off-the-shelf product save for that bit of customization (the firmware plus key overlay and manual/packaging).

You aren't the only one, in fact there are countless people who want the Casio CFX-400 scientific calc watch re-introduced.

Casio still sell the databank version that has the exact same case and keys as the original, all it needs as you say if the firmware, LCD,and key overlay.

For those that aren't aware, the Casio CFX-400 is one of the most highly sort after retro watches, they regularly go for over $1000 on ebay. Even dead ones fetch many hundreds. And this is for a watch that you could originally buy for $20.

Hmm, perhaps it's video blog time! Casio might listen like Microchip did!

Dave.


#60

Casio has already released many older watches in their retro-series. Maybe we could convince them to do so with an (improved) calculator watch.


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