[TI-H] Re: Building your own calculator
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[TI-H] Re: Building your own calculator
not to piss on your parade, but you've got a whole lot of work ahead of you.
it's the reason TI has a design team funded by millions of dollars and
engineers with PhD's.
probably the largest problem is the board itself. you have to design a
circuit board from scratch that includes a CPU, memory, display, clock, and
all the circuitry necessary to support them all. rip open your TI sometime.
you have to re-create that. then you have to have your design printed by a
one-off board printer, which will cost you around $300, depending on how
many layers of copper end up in your board.
it would be easier and maybe wiser to start with something a bit simpler;
have you ever built a simple microcomputer before? make yourself a little
microcontroller, a PIC would be perfect, and program it. assemble it on a
breadboard or perfboard. then you can work up to more complex tasks, like a
microcomputer built around the z80. this essentially WOULD be a calculator,
if you programmed it -- the TI-82/3 and TI-85/6 are powered by the z80.
if you want to build a portable computer that kicks ass, try the LART. you
can find info at http://www.lart.tudelft.nl/. the LART is a small
StrongARM-based computer that was designed to pack as much power into as
small a design as possible.
obviously, you're not going to be able to design your own microcomputer from
scratch without any electrical engineering knowledge. i probably could, but
i have 3 years of EE behind me. even so, it would be far easier to work with
an existing design. there are many schematics for simple PIC setups that you
could assemble on a breadboard, or if you feel comfortable with fine-pitch
surface-mount soldering and you have a good iron, a steady hand, and a
decent magnifier, you could do your own PCB work with something like the
LART.
good luck,
--nick
-----Original Message-----
From: ti-hardware-bounce@lists.ticalc.org
[mailto:ti-hardware-bounce@lists.ticalc.org]On Behalf Of David Phillips
Sent: Friday, November 16, 2001 7:42 AM
To: ti-hardware@lists.ticalc.org
Subject: [TI-H] Building your own calculator
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,
--
David Phillips <david@acz.org>
http://david.acz.org/
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