[TI-H] Re: Building your own calculator

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[TI-H] Re: Building your own calculator


David,

You will find that designing or hacking a system which can support bsd 
or linux is going to cost substantially more than any of the 
calculators, and even more than a PDA.

You might try checking out the itsy (compaq research) or, as mentioned 
above, the lart.

Quite frankly, you'll spend less and be more productive if you simply 
buy a cheap compaq IPAQ.  The greyscale models can be had online for 
$200, the 3635 color model can be had for $300 (after the $150 rebate).

I would be stunned if you could make or get a cheaper system with half 
the hardware features for less than double what they cost.

Compaq supports Linux on the IPAQ.  My suggestion would be that you'd 
accomplish more by taking existing hardware and bending it to your will 
(maybe taking the 89, and making your own OS, or taking an IPAQ and 
adapting one of the dozens of symbolic math apps for it's smaller 
screen) than by starting from scratch.

If you insist on starting with making your own hardware from scratch, 
you've got a long road ahead of you.  Start by checking out 
news://comp.arch.embedded and a few other newsgroups.  Look into 
projects such as the lart, yopy, itsy, etc. They'll have some good links.

-Adam

David Phillips wrote:

> As was mentioned on this list earlier, I am interested in building a calculator or similiar portable from scratch.  The goal is knowledge, rather than the final product, as it would obviously be cheaper, both time and money wise, to buy an available product.  I hope that others on this list are interested in the idea, and can possibly offer some tips on getting started.
> 
> There are a lot of different directions that this project can be taken.  I would be happy with anything programmable that has user input and visual output.  Something as simplistic as the Dreamcast memory unit would be fine.  There are obviously many things available to hack on, but takes all the fun out of it.  I'm specifically interested in being able to use available CPU's, displays, flash ROM's, etc., and put them together to make a working device.  If anyone has seen the cool projects that Kevin Horton has done, then you'll know what I'm after.  How do you go from understanding basic electronics to hacking things together?
> 
> Unfortunately, I don't know anyone personally who does this sort of thing, so I'm looking for references on the subject.  Electrical engineering is of course a well defined field with an immense number of references, but finding something aimed at a beginner that is easily understandable might be difficult to find.  I didn't see anything on Amazon.com.  I will likely check out some book stores this weekend and see if they have anything useful.  If anyone knows of any helpful references, please let me know.
> 
> Something of this scope might be way beyond what any beginner could do, and if that is the case, I would like to find something that presents a clear path to learn what is necessary.  I have been programming and working with computers for over ten years, and I could program anything, given sufficient resources.  That sort of knowledge takes a long time to acrue, and I would like to get there quicker with hardware.  I want to be able to get to that point with hardware.
> 
> If we choose to build a calculator, then it's going to need software.  I see three possible methods:
> 
> 1) Write it from scratch
> 2) Use existing free software
> 3) Emulate existing non free software
> 
> I am not interested in writing a calculator OS from scratch.  However, others might be, and that could get interesting.  I believe that the OS for some of the HP calculators are open source, or at least part of it.  Having a totally open source calculator would be pretty cool.  If this route were to be taken, then you would need to be able to produce enough units to meet demand.  Not having the cost be prohibitively high would be a plus.  The basic plan for the OS could direct the design of the hardware.
> 
> There are several free calculator type programs that could be used.  The calculator could run Linux or a BSD variant, and utilize existing software.  Being that most existing software I've seen is of a GUI nature designed for a desktop environment, making it work on a calc might be hard.  There are likely CAS systems that could be fairly easily adapted.  
> If the system were reasonably powerful, it could simply emulate an existing calc, such as the TI-86, TI-89 or an HP calc.  Of course, it doesn't have to be a calculator at all.  If I could build something that I could program to play tic-tac-toe, I would be happy.  The software is an after thought.
> 
> Is anyone else out there interested in helping out in any way?  I need to know who can help with the hardware, who would like to work on the software for it, who would be interested in producing units for people, and who would want to buy one of the units.  I'd think that someone would start making a few and selling them once a working design was perfected, as with similiar hardware mods like link cables.
> 
> I remember there used to be some people on this list who knew hardware really well, like Grant Stockly.  Any of you want to offer suggestions?
> 
> 
> Later,
> 
>
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