What about a real refitting of old 41s?



#16

How about this:

The electronics of an old 41 refitted into a new metal case and with room for AA or AAA batteries instead of the dying breed of N-cells?

Is there anyone around here that could do such a job?


#17

Um, I think you mean "41C" not 41S - unless that means I have to collect yet another model :)

The problem you speak of is what dogs any hobbyist production of a new calculator - the electronics/PCB and firmware are easy and acheivable in a garage.

But doing a nice case/keyboard costs huge $$$$ for a production run just even to get started. And I am assuming you mean something that looks/works properly, not a bunch of Radio Shack SPST pushbutton switches in/on an aluminum project box :)


That's the whole problem with the OpenRPN project, at least as far as I've seen - everyone's worrying about choice of CPU (irrelevant as even a competent 4-bitter can do a fine job) or tricky electronic designs or minor firmware issues, when the real issue is keytops and case.


Bill Wiese

San Jose CA USA


#18

Hallo!

Quote:
Um, I think you mean "41C" not 41S ...

No, I think that 41s is the plural of 41. Mathematically correct, he should have written: n * 41 with n=1...infinity :-)

But the idea is not bad at all. If one would keep the electronics and keyboard together, a nice housing could be machined from a small block of alumiuim quite easily by a skilled craftsman. Even more easily on a numerically controlled milling machine.

I would buy one (at a reasonable price, say 50 Euros?), because I have a 41 with corroded battery contacts that could do with a new housing with integrated AAA cells.

Greetings, Max


#19

Quote:
But the idea is not bad at all. If one would keep the electronics and keyboard together, a nice housing could be machined from a small block of alumiuim quite easily by a skilled craftsman. Even more easily on a numerically controlled milling machine.

I would buy one (at a reasonable price, say 50 Euros?), because I have a 41 with corroded battery contacts that could do with a new housing with integrated AAA cells.


Max,

50Euros (~ $80 US) for small-volume CNC mill work would be difficult to find I think. It takes some skill for setup etc. and would involve lost 'opportunity costs' for more profitable higher-volume projects.

It seems all our CNC shops that handle smaller volumes here are always busy - except for the right price, which'd be prohibitive for hobby projects.

The closest I can find for limited panel-type applications is http://www.frontpanelexpress.com ...

A friend is trying to start a firearm company for a new innovative rifle receiver (that is, not the whole rifle, just one fairly simple block that has only a few really critical holes/openings) and cannot get *any* time on CNC machines at firearms-authorized firms. Even if he were to go to a non-licensed machining firm and directly oversee production run day/night under his license, they're still booked up/cost too much.


Bill Wiese

San Jose CA


#20

Has anybody tried this gizmo for making calculator cases: the Sears Compucarve (http://www.sears.com/sr/javasr/product.do?pid=00921754000)

It is basically a cheap CNC machine. They claim it will work on wood and plastic. Maybe it would do OK on aluminum, too. I'm not sure how fine the detailing can be. It can be had cheaper ($1700) if you are a member of the Craftsman Club! In any case, it's a lot cheaper than the Versalaser carbon dioxide "printer" which has similar capabilities.

#21

Quote:
That's the whole problem with the OpenRPN project, at least as far as I've seen - everyone's worrying about choice of CPU (irrelevant as even a competent 4-bitter can do a fine job) or tricky electronic designs or minor firmware issues, when the real issue is keytops and case.

Maybe designing case and keytops could be done using rapid prototyping. There's free software from www.alibre.com and www.emachineshop.com which would fit the bill. As far as hardware is concerned, calipers to measure the HP case are needed; $20 or so. www.emachineshop.com and www.redeyerpm.com offer prototyping services. Biggest cost is probably the time spent designing the cad model.

regards,

koen


#22

I'd disagree with Koen, the time necessary to create a CAD model uses the one resource that a hobbyist is plentiful in: personal voluntary time!

Hobbyists differ from businessmen in one key characteristic: The former will happily engage in a zero-ROV (financial) project simply because he/she enjoys it, or is nostalgic about a subject. We work for "free" through the night on hobby projects, and then wake up and work the daylight hours for profit.

The monetary cost is greatest when short-run, highly custom equipment is created using current/modern industrial fab shop tools that are not subsidized (for our benefit).

Even more curious is the desire to MAKE a calculator. Granted, this is a DIY culture (of which I am more interested in the numerical DIY aspect, ie. programming). I can appreciate it, but wonder that you all are not more interested in your day-jobs?

I can hardly wait to get to work in the mornings, and often put in 11-12 hours because I get caught up in my work. Lately, when I get home, I'm spent, and look forward to reading, or mentally revisiting current project issues in the evenings.

I am a structures analyst/design guy on a new suborbital space vehicle, so job-related excitement is par for the course, but I'm still somewhat startled that people are still pursuing these fab projects. Don't take this the wrong way, I don't mean any harm. I'd really like to know more of your perspectives on how being a tech-minded person (for those of you who are) has worked out wrt careers, etc.

ECL


#23

Quote:
I'd disagree with Koen, the time necessary to create a CAD model uses the one resource that a hobbyist is plentiful in: personal voluntary time!

Hobbyists differ from businessmen in one key characteristic: The former will happily engage in a zero-ROV (financial) project simply because he/she enjoys it, or is nostalgic about a subject. We work for "free" through the night on hobby projects, and then wake up and work the daylight hours for profit.

The monetary cost is greatest when short-run, highly custom equipment is created using current/modern industrial fab shop tools that are not subsidized (for our benefit).

Even more curious is the desire to MAKE a calculator. Granted, this is a DIY culture (of which I am more interested in the numerical DIY aspect, ie. programming). I can appreciate it, but wonder that you all are not more interested in your day-jobs?

I can hardly wait to get to work in the mornings, and often put in 11-12 hours because I get caught up in my work. Lately, when I get home, I'm spent, and look forward to reading, or mentally revisiting current project issues in the evenings.

I am a structures analyst/design guy on a new suborbital space vehicle, so job-related excitement is par for the course, but I'm still somewhat startled that people are still pursuing these fab projects. Don't take this the wrong way, I don't mean any harm. I'd really like to know more of your perspectives on how being a tech-minded person (for those of you who are) has worked out wrt careers, etc.


Having just designed and built my own RPN calc from scratch, I can give you the reasons why I did it at least:
1) It's fun
2) What I wanted was not available commercially (old or new) so I simply did it myself. This is probably my main reason.
3) I'll hopefully get some kudos for it.
4) Did I mention it's fun?

Also, it's not much work either. My first prototype took around 30 hours of actual work from blank schematic and no C code, before I had it in my hands and could push the buttons and see calcs on the LCD. That of course doesn't include general procrastination, napkin sketches, and just thinking about stuff!

Dave.


#24

Dave,

That's pretty impressive (and cool!)

I'm "for" doing what you did. 30hrs is quite rapid!

I should probably have been more clear in my earlier criticism. What appears somewhat futile (I know many disagree) is the pursuit of custom injection-molded 2X keys, etc.

But perhaps I'm just wrong here. There's certainly nothing wrong with dreaming (Howard), I do that too. I suppose it is the devotion to lust-ware (ie. multiple keyboard schemes, processor trade-offs) that surprised me.

Then, I sit around and make paper/glue scale models of various aircraft wing layouts :)

Thanks for the thoughts,

ECL


#25

Quote:
Dave,

That's pretty impressive (and cool!)

I'm "for" doing what you did. 30hrs is quite rapid!

I should probably have been more clear in my earlier criticism. What appears somewhat futile (I know many disagree) is the pursuit of custom injection-molded 2X keys, etc.

But perhaps I'm just wrong here. There's certainly nothing wrong with dreaming (Howard), I do that too. I suppose it is the devotion to lust-ware (ie. multiple keyboard schemes, processor trade-offs) that surprised me.

Then, I sit around and make paper/glue scale models of various aircraft wing layouts :)

Thanks for the thoughts,

ECL


Yes, you can get easily caught up in "the dream" and never achieve anything, that's why I forced myself to make some hard decisions up front and get that first prototype done and dusted.

I'm spending a bit more time now on the 2nd prototype which will hopefully be the final released product. Having that first prototype to play with quickly really showed me what's important and what's not, what works and what doesn't, and gives you confidence that you are on the right track.

Dave.

#26

I think that DIY calculators are appealing to geeks like me because of two things. First, I have lots of ideas about how my ideal calculator should operate. Second, software simulations of classic calculators (some of which are closer to my ideal than anything on the market today) are less than satisfactory because of the lack of a decent keyboard and portability. So I naturally dream of building the ideal calculator frame and filling it with the ideal calculator software.

Now, I'm a software guy. I started playing around with a soldering iron a couple of years ago just for fun. But I'd never be able to fabricate in the real world anything like what I have in mind. But that is all beside the point. Just because it isn't possible for me to build my ideal calc doesn't stop me from wishing I could, and dreaming about the result.

Regarding work/hobby balance, sometimes I don't get enough sleep. 8) Also, my software hobbies complement my day job as a systems engineer. That's not very balanced, but I've never been very good at balance anyway. 8)

Regards,
Howard

#27

Quote:
Maybe designing case and keytops could be done using rapid prototyping. There's free software from www.alibre.com and www.emachineshop.com which would fit the bill. As far as hardware is concerned, calipers to measure the HP case are needed; $20 or so. www.emachineshop.com and www.redeyerpm.com offer prototyping services. Biggest cost is probably the time spent designing the cad model.

eMachineShop is nice (and easy) but not that cheap. For the cost of a rapid-prototype case you could probably buy yourself another real 41 with a pristine case.

Dave.


#28

Quote:
For the cost of a rapid-prototype case you could probably buy yourself another real 41 with a pristine case.

Nah, it's plastic.

What I need is an aluminium case with the interior, the LCD, the keyboard and the ports from my 41CX. And it should take three AAA batteries. That's all I need. And I would be happy to pay USD 200 for it.


#29

Quote:


Nah, it's plastic.

What I need is an aluminium case with the interior, the LCD, the keyboard and the ports from my 41CX. And it should take three AAA batteries. That's all I need. And I would be happy to pay USD 200 for it.


eMachineShop can do it in aluminium, or any other material you like. But for $200ea you'd have to split the cost with quite few others.

Dave.

#30

Quote:
The electronics of an old 41 refitted into a new metal case and with room for AA or AAA batteries instead of the dying breed of N-cells?

Is there anyone around here that could do such a job?


An interesting idea, but it's almost the opposite of what's really needed. Designing replacement electronics for the 41C is a relatively easy task. It's the case design and manufacturing that is difficult and expensive.

I've recently been learning the rudiments of industrial design with SolidWorks and a 3D printer. It's great for prototyping, but the cost is far too high for production use. A set of plastics for something similar to the 41C has a materials cost of about $50 with a 3D printer (fused deposition modeling).


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