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what chip to use? — Parallax Forums

what chip to use?

ArchiverArchiver Posts: 46,084
edited 2004-01-13 01:52 in General Discussion
A handicap friend has asked my help to build a circuit to control a 3
level home brew elevator. I have designed a logic circuit consisting
of several logic IC's but have finally decided to look into applying
a microchip to replace the numerous logic chips. Due to the large
number of Microchips available and the necessity to now teach myself
programming, I'm stumped at where to begin to choose what Microchip
to use. Can anyone help?
The logic circuit I have put together will monitor the ON – OFF state
of five inputs to control three separate outputs, 1 for a brake, 2
for the 110v AC motor, 15 amp max (two separate wires for one
direction two for the other reverse direction ). I plain on
connecting 2 solid state relays (SST-240D25) to the outputs of a
microchip to switch AC. Also, would like to use three infrared or
such from elevator to eliminate any need for wires from elevator
although we do have two wire ( 110v ) coming off of a spring spool to
elevator.
I hope to be able to program a chip to distinguish the latch on off
state of the outputs based on the state of the 5 inputs.
The output of my present logic circuit controls to JK flip-flops used
for latching on – off (one up direction the other down ) and
feeding the AND gate that controls the brake action. I hope using a
Microchip wont be as much trouble as the countless hours spent
designing the logic circuit that at first seemed simple. Any input
will be greatly appreciated. Thanks T.O.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-01-12 19:36
    None easier, quicker to learn, better supported, and great
    documentation.......the BASIC STAMP.

    ken


    In a message dated 1/12/2004 11:27:47 AM Pacific Standard Time,
    tloleksy@y... writes:
    I hope to be able to program a chip to distinguish the latch on off
    state of the outputs based on the state of the 5 inputs.
    The output of my present logic circuit controls to JK flip-flops used
    for latching on
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-12 19:55
    Thanks for the fast response, how ever there are
    still many to choose from ( which one? ) and would
    seem like over kill if it were possible to put
    together a pic or microprocessor circuit that was
    capable of the task, cost is a big issue for many
    handicap individuals. Thanks T.O.

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  • ArchiverArchiver Posts: 46,084
    edited 2004-01-12 20:37
    HIGHLY recommend the Basic Stamp, in the BOE board.
    They (Parallax) have solved the issues of
    power supply, EEPROM programmer, PIC assembly,
    PIC programming, brown-out recovery, debugging.

    As long as you don't use too much current,
    (which will reset the chip)
    the BS2 lets you try almost anything.

    Its only drawback from PIC's -- it's not as fast,
    and it doesn't have interrupts, and it costs
    $50.00 for the Module.

    Otherwise, it's MUCH easier to program, verify
    it's correct, put in-circuit, use RS-232 with,
    you name it. And a decent PIC programming
    setup is going to cost more than $50.00.

    A 100 line program in PBasic should be sufficient
    to do what you are attempting. Short to write,
    short to debug. Running the wires to support
    the sensors will probably take longer than writing
    and debugging the code in PBasic.

    For one-of solutions like yours, I don't think
    you can have a more cost-effective solution.

    --- In basicstamps@yahoogroups.com, "tloleksy" <tloleksy@y...> wrote:
    >
    > A handicap friend has asked my help to build a circuit to control a
    3
    > level home brew elevator. I have designed a logic circuit
    consisting
    > of several logic IC's but have finally decided to look into
    applying
    > a microchip to replace the numerous logic chips. Due to the large
    > number of Microchips available and the necessity to now teach
    myself
    > programming, I'm stumped at where to begin to choose what Microchip
    > to use. Can anyone help?
    > The logic circuit I have put together will monitor the ON – OFF
    state
    > of five inputs to control three separate outputs, 1 for a brake, 2
    > for the 110v AC motor, 15 amp max (two separate wires for one
    > direction two for the other reverse direction ). I plain on
    > connecting 2 solid state relays (SST-240D25) to the outputs of a
    > microchip to switch AC. Also, would like to use three infrared or
    > such from elevator to eliminate any need for wires from elevator
    > although we do have two wire ( 110v ) coming off of a spring spool
    to
    > elevator.
    > I hope to be able to program a chip to distinguish the latch on
    off
    > state of the outputs based on the state of the 5 inputs.
    > The output of my present logic circuit controls to JK flip-flops
    used
    > for latching on – off (one up direction the other down ) and
    > feeding the AND gate that controls the brake action. I hope using
    a
    > Microchip wont be as much trouble as the countless hours spent
    > designing the logic circuit that at first seemed simple. Any input
    > will be greatly appreciated. Thanks T.O.
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-12 20:48
    It occurs to me you really might want to know
    a PIC chip to use -- in which case:
    the 16F876 (28-pin, narrow DIP) can program
    itself, once a bootloader has been installed in
    the chip. The 16F877 (40-pin, wide DIP) is the
    same internally, with additional I/O pins.

    Both can use 20 Mhz resonators, take 4 clock cycles
    per instruction, and so can run at 5 MIPS.
    You can check this chip out on the Microchip site.
    But I still stick with what I said earlier --
    the BS2 (plain) or BS2sx (faster) is the
    easiest and most cost-effective way to go.

    --- In basicstamps@yahoogroups.com, "Allan Lane" <allan.lane@h...>
    wrote:
    > HIGHLY recommend the Basic Stamp, in the BOE board.
    > They (Parallax) have solved the issues of
    > power supply, EEPROM programmer, PIC assembly,
    > PIC programming, brown-out recovery, debugging.
    >
    > As long as you don't use too much current,
    > (which will reset the chip)
    > the BS2 lets you try almost anything.
    >
    > Its only drawback from PIC's -- it's not as fast,
    > and it doesn't have interrupts, and it costs
    > $50.00 for the Module.
    >
    > Otherwise, it's MUCH easier to program, verify
    > it's correct, put in-circuit, use RS-232 with,
    > you name it. And a decent PIC programming
    > setup is going to cost more than $50.00.
    >
    > A 100 line program in PBasic should be sufficient
    > to do what you are attempting. Short to write,
    > short to debug. Running the wires to support
    > the sensors will probably take longer than writing
    > and debugging the code in PBasic.
    >
    > For one-of solutions like yours, I don't think
    > you can have a more cost-effective solution.
    >
    > --- In basicstamps@yahoogroups.com, "tloleksy" <tloleksy@y...>
    wrote:
    > >
    > > A handicap friend has asked my help to build a circuit to control
    a
    > 3
    > > level home brew elevator. I have designed a logic circuit
    > consisting
    > > of several logic IC's but have finally decided to look into
    > applying
    > > a microchip to replace the numerous logic chips. Due to the large
    > > number of Microchips available and the necessity to now teach
    > myself
    > > programming, I'm stumped at where to begin to choose what
    Microchip
    > > to use. Can anyone help?
    .
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-12 20:52
    Hi Terry,
    I got into Basic Stamps designing devices for a handicapped friend also.

    If you don't already have a programmer for PICs, AVRs etc., you will come
    out way ahead on cost and especially time by going with one of the basic
    Stamps. Any of the stamps can handle your chore but I would probably start
    with a BS2 if for no other reason than pin count. If you want to produce
    your project commercially in the future, you can always port it to one of
    the cheaper chips or buy the interpreters etc. from Parallax and roll your
    own.

    Jeff
    Original Message
    From: Terry Oleksy [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=pYnRjFZrBuT1QEsCRCgY9iEv2-dxIE2Jbc5jR-C2kHJKbG70h0LsSDjEMVRX1Ud1PhmfQfoEbLk]tloleksy@y...[/url
    Sent: Monday, January 12, 2004 2:55 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] what chip to use?

    Thanks for the fast response, how ever there are
    still many to choose from ( which one? ) and would
    seem like over kill if it were possible to put
    together a pic or microprocessor circuit that was
    capable of the task, cost is a big issue for many
    handicap individuals. Thanks T.O.
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-13 01:32
    The following is a quote from Parallax Elements of Digital Logic. Chapter #8
    page 99
    "The first step in solving any problem is to clearly define the task to be
    accomplished
    The next step is to break that task into sub-functions.
    This process continues until all the sub functions are reduced to the point
    where they seem easy to implement.
    Then, each sub-function is meticulously implemented and individually tested.
    Once all the sub-functions are complete and work perfectly, they are then
    combined and tested as a whole.
    Of course it never works the first time through. And, after the panic wave
    ripples through the fabric of your soul because your deadline is about to
    expire, the troubleshooting begins. The trouble, invariably, is caused by a
    ubiquitous computer bug: the PEBCAC, (Problem Exists Between Chair and
    Computer.)"
    The Parallax site has loads of documentation you can download to broaden
    your level of understanding. An excellent book for help and reference is
    "The Art of Electronics" by Paul Horowitz and Winfield Hill, 2nd edition
    Publisher Cambridge.
    When you invest time in your own learning process, Then you will see more
    rewarding results in your projects.
    Regards, Steve Chapman

    Original Message
    From: "tloleksy" <tloleksy@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, January 12, 2004 11:12 AM
    Subject: [noparse][[/noparse]basicstamps] what chip to use?


    >
    > A handicap friend has asked my help to build a circuit to control a 3
    > level home brew elevator. I have designed a logic circuit consisting
    > of several logic IC's but have finally decided to look into applying
    > a microchip to replace the numerous logic chips. Due to the large
    > number of Microchips available and the necessity to now teach myself
    > programming, I'm stumped at where to begin to choose what Microchip
    > to use. Can anyone help?
    > The logic circuit I have put together will monitor the ON - OFF state
    > of five inputs to control three separate outputs, 1 for a brake, 2
    > for the 110v AC motor, 15 amp max (two separate wires for one
    > direction two for the other reverse direction ). I plain on
    > connecting 2 solid state relays (SST-240D25) to the outputs of a
    > microchip to switch AC. Also, would like to use three infrared or
    > such from elevator to eliminate any need for wires from elevator
    > although we do have two wire ( 110v ) coming off of a spring spool to
    > elevator.
    > I hope to be able to program a chip to distinguish the latch on off
    > state of the outputs based on the state of the 5 inputs.
    > The output of my present logic circuit controls to JK flip-flops used
    > for latching on - off (one up direction the other down ) and
    > feeding the AND gate that controls the brake action. I hope using a
    > Microchip wont be as much trouble as the countless hours spent
    > designing the logic circuit that at first seemed simple. Any input
    > will be greatly appreciated. Thanks T.O.
    >
    >
    >
    >
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  • ArchiverArchiver Posts: 46,084
    edited 2004-01-13 01:52
    I've been oscillating about posting this concern, but my first reaction to
    this question about controlling an elevator for a handicapped friend caused
    an immediate involuntary clenching of that special pucker muscle. Please be
    aware that most parts for elevators need to be certified, licensed, and
    inspected by a local authority. This is to prevent accidents from happening,
    and liabilities from occurring. It's one thing to write your own program for
    a data logger or a robot or even an industrial process, but quite another
    when a human can be injured or worse from a program bug. Please, please,
    please, review this with any local authorities before you build it. And if
    you do build it, make sure you test, test, test, and put in fail safes. I
    understand wanting to save money and build helpful things for those who
    can't afford the big stuff, but that will all be worthless if someone gets
    hurt. We all joke about Murphy's Law, but it's one of those universal
    constants that we'll never get around.

    Let's be careful out there...

    Mike Sokol

    " One should not increase, beyond what is necessary,
    the number of entities required to explain anything"...
    -William of Occam-


    Original Message
    From: "tloleksy" <tloleksy@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, January 12, 2004 2:12 PM
    Subject: [noparse][[/noparse]basicstamps] what chip to use?

    Ref: A handicap friend has asked my help to build a circuit to control a 3
    level home brew elevator.
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