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Build my own calculator

Discussion in 'Electronic Basics' started by Gunnar G, Jun 14, 2005.

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  1. Gunnar G

    Gunnar G Guest

    Is it hard to build your own calculator? Now I'm not talking about something
    like the latest HP calculator but something between that and the ENIAC.
    The ability to add numbers would be a great start.
    Has anyone done this, any good internet resources for this?
  2. mike

    mike Guest

    At what level do you want to start?
    Calculator chip level?
    Programmable Logic?
    Discrete complex chips?
    Discrete simple chips?
    Resistors and transistors?
    Beach sand to make silicon chips?
    Piles of rocks?

    You're starting a project that is conceptually simple, but annoyingly
    complex to implement. And when you're done, it will be HUGE and useless.

    Motivation is the key to learning. If you start with
    a weak goal and a frustrating path to get there, you'll never finish it.

    Pick an outcome you can use when you're done and a simpler
    implementation path. Design a learning project
    around that. A lot of people start with home automation projects.

    Return address is VALID but some sites block emails
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  3. BobG

    BobG Guest

    The intel 4004 cpu chip was designed to put in a calculator. So why not
    get a dev bd like an olimex mt128 with an lcd and some buttons, and
    write a specialty calculator for it.
  4. Something in between is a wide, wide area. A calculator with only four basic
    functions can be build with almost any micro that has enough I/O-pins two
    read the keyboard and drive the display of your choice. It may become pretty
    slow if you go into larger numbers but it will nevertheless be faster then
    the Eniac. (But heavier, slower and more energy hungry then the next simple,
    cheap pocket calculator.) I was told that Microchip has a application note
    treating floating point calculations but I did not check out myself.

    petrus bitbyter
  5. Bob Monsen

    Bob Monsen Guest

    The 12 and 16 series have no multiply operation, so the floating point
    libraries supplied by microchip are immense and slow. However, the
    current crop of low-end pics are almost certainly faster, and hold more
    code than the original HP calculators. A PIC18, with a multiply, would
    make it even easier.

    On the other hand, you can buy a casio fx-115MS that does everything
    from complex numbers to integration for about $15, which is undoubtedly
    far less than you would spend on parts, not counting programmers and
    test tools to build it.

    Another project, which is probably easier to pull off, and which will
    give you lots of puzzles to solve and a thing you can use at the end
    would be to build a VFD clock. You can get cheap vacuum fluorescent
    display tubes at surplus places, They look cool, but require you to
    design and implement various power supplies to handle the
    grid/filament/anode. Take the timebase off of the powerline, and use
    CMOS logic or something like that to generate the clock display. A
    microcontroller (PIC or something) would make it easier, but you would
    have to learn to program it.

    That will be a fairly big project, not too hard, and you'll have an
    interesting looking clock afterwards, not a slow, feature-bare calculator.
  6. Many AVR processors can use the floating-point routine in the file

    I googled for
    avr floating-point

    The link above is one of the links I found.

    Multiply and Divide Routines

    Using the AVR Hardware Multiplier Updated: Feb 24, 2005
    Examples of using the multiplier for 8-bit arithmetic.

    If the goal is a pocket calculator a modern microprocessor is the
    perfekt choice.
    It has better instruktions and is a lot faster that the first pocket
    calculator processors.
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