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HP Forum Archive 18

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Calculator Design
Message #1 Posted by jonsproject on 27 Aug 2008, 12:12 a.m.

I have an idea for a calculator but I don't have the background or expertise to pursue a prototype based on my limited understanding. It incorporates some simple math calculations and a storage feature that will allow for multistep selections of various categories. I would like to perform the math calculations and storage options on the same screen but I am not familiar with whether there is software that will allow for this type of function. Any help out there? Thanks.

      
Re: Calculator Design
Message #2 Posted by reth on 27 Aug 2008, 6:44 a.m.,
in response to message #1 by jonsproject

Yea, start reading this forum, read it all and then ask again

            
Re: Calculator Design
Message #3 Posted by jonsproject on 27 Aug 2008, 10:59 a.m.,
in response to message #2 by reth

I read it for the first time last night and you guys are way over my head, and the applications you are discussing are far more complicated than what my idea requires. I will continue to review the material now that I've found the right forum but I also have some questions that will help get me there faster. If I sound like an idiot when I ask them I hope you'll put up with it, this is way outside my area of expertise.

For instance:

Can I use the same screen to display math logic and graphic icons for choice selection?

      
Re: Calculator Design
Message #4 Posted by cyrille de Brébisson on 27 Aug 2008, 8:35 a.m.,
in response to message #1 by jonsproject

hello,

if you know how to program, you could use the HP 20b as a development platform...

cyrille

            
Re: Calculator Design
Message #5 Posted by jonsproject on 27 Aug 2008, 11:02 a.m.,
in response to message #4 by cyrille de Brébisson

I don't know how to program but I'm willing to learn. I'll go check out the HP20b. Where do I go to get the platform and (here's my first idiot question) how do I go about arranging it for my needs. Yeah, that's right, I'm starting from square one.

Edited: 27 Aug 2008, 11:07 a.m.

                  
Re: Calculator Design
Message #6 Posted by Bruce Bergman on 27 Aug 2008, 11:37 a.m.,
in response to message #5 by jonsproject

Probably the best resource for getting started with the 20b is to visit the 20b repurposing site:

http://hpwiki.fatcity.com

There's a ton of information there, including how to get started, what you need, etc. It's a community site, so please feel free to add information as you learn -- things that we didn't mention, helpful stuff missing from the site, etc.

thanks, bruce

                        
Re: Calculator Design
Message #7 Posted by jonsproject on 27 Aug 2008, 4:37 p.m.,
in response to message #6 by Bruce Bergman

Thanks Bruce, I'll check it out, I appreciate the link.

      
I'd suggest not to go with a calculator.
Message #8 Posted by Frank Boehm (Germany) on 27 Aug 2008, 11:11 a.m.,
in response to message #1 by jonsproject

A PalmPC has a larger display and is probably much easier to program (IDEs are available) and have the size of a pocket calculator. You could even do the development on your PC without having to purchase a PalmPC (there are pocket calculator emulators available too). But maybe you could enlighten us a bit more about your idea - it's hard to tell what your project is about.

            
Re: I'd suggest not to go with a calculator.
Message #9 Posted by jonsproject on 27 Aug 2008, 5:34 p.m.,
in response to message #8 by Frank Boehm (Germany)

I thought about the palm PC but I have one and I don't really use it that often and I don't know if the application I'm creating would be as wide ranging as it would be if I simplified it onto a small pocket calculator. I do have a very inexpensive pocket calculator that I use daily.

I'll try to explain the type of use required:

I looked at the HP20b financial calculator and the look is along the lines of what I want to do however I only need half the functions and hopefully half the size.

I would like to be able to do calculations and once I arrive at a result, plug that result into a category with a date tag. For instance I would like to calculate the difference between two observed quantities and once finding the result log that result into a category selected by the use of a curser that highlights a particular option. When the option is highlighted an enter button is pressed which either brings up another subcategory or arrives at the category into which I want to log the data, depending on the variations within a category.

Step 1 - Press key to select category

Display - Shows three options with middle option highlighted

Step 2 - Press enter to select highlighted category option or left/right arrow key to move curser and highlight desired category.

Display - Next set of sub categories are displayed on screen, one of which is highlighted.

Step 3 - Press enter to select highlighted category or use left/right arrow key to hightlight another category option.

Display - Target sub category is arrived at and selected by pressing enter key.

Step 4 - Calculation is performed to arrive at result and once result is obtained enter key is pressed to insert result into category.

Display - Shows result along side of empty date field and date is typed in using number keys.

Step 5 - Press enter key to finish category entry.

                  
Re: I'd suggest not to go with a calculator.
Message #10 Posted by Borja on 28 Aug 2008, 3:50 a.m.,
in response to message #9 by jonsproject

Looks like a standard application for many portable devices.

20 years ago I used to do similar things, using barcode readers, etc, on this platform:

http://en.wikipedia.org/wiki/Psion_Organiser

Depending on the calculations involved, it won't be hard. You could do this with a powerful programmable calculator, a BASIC pocket computer, etc.

                  
How about data transfer?
Message #11 Posted by Frank Boehm (Germany) on 28 Aug 2008, 6:39 a.m.,
in response to message #9 by jonsproject

I'd say this will be possible on most pprogrammable calculators dating back to the 80s (as long as they have programmable menu keys). The major issue is: do you want a data transfer of some kind?

      
Re: Calculator Design
Message #12 Posted by DaveJ on 27 Aug 2008, 5:39 p.m.,
in response to message #1 by jonsproject

Quote:
I have an idea for a calculator but I don't have the background or expertise to pursue a prototype based on my limited understanding. It incorporates some simple math calculations and a storage feature that will allow for multistep selections of various categories. I would like to perform the math calculations and storage options on the same screen but I am not familiar with whether there is software that will allow for this type of function. Any help out there? Thanks.

You need to tell us more about your project details and it's intended application, what is it exactly you are trying to do?

i.e. Why can't you just use a PC or a pocket PC/Palm?

Here is my custom made calculator: http://www.calcwatch.com

Dave.

            
Re: Calculator Design
Message #13 Posted by jonsproject on 27 Aug 2008, 7:54 p.m.,
in response to message #12 by DaveJ

Great watch Dave. I don't know if I can describe it any better than I have. I've got some drawings I did on my pc but it's a pretty standard looking pocket calculator. It's just the features I explained in the previous post that I'm not sure how to incorporate. As this process continues I'll figure it out and hopefully wind up with a prototype I can work the kinks out of.

                  
Re: Calculator Design
Message #14 Posted by Jeff Kearns on 27 Aug 2008, 8:03 p.m.,
in response to message #13 by jonsproject

Hi Jon,

I have a really hard time deciphering your intended application. It appears as though you are confusing 'category' for 'storage register'. I also assume that any RPL-based calculator (or the venerable HP 41C) could be programmed to do what you are looking for, namely attach or append some sort of date-tag to a calculated result and store it somewhere, but again it is hard to know exactly what you intend the calculator to be used for. A simple, practical example would be helpful.

Good luck!

Jeff Kearns

                  
Re: Calculator Design
Message #15 Posted by DaveJ on 27 Aug 2008, 8:23 p.m.,
in response to message #13 by jonsproject

Quote:
Great watch Dave. I don't know if I can describe it any better than I have. I've got some drawings I did on my pc but it's a pretty standard looking pocket calculator. It's just the features I explained in the previous post that I'm not sure how to incorporate. As this process continues I'll figure it out and hopefully wind up with a prototype I can work the kinks out of.

Ok then, how about start by telling us why you need to design your own calculator hardware?

What don't existing calculators do that is forcing you to consider your own design?

Why can't use you an existing programmable calculator? Some of them are very customisable, in fact you can reprogram them from scratch if needed.

Do you have a background in hardware design?

Dave.

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