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Re: Jim's Project

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  • JIM
    Hi Jo, Thanks again for the interest. I beleive i have the timings figured out but wont know until the chassis and legs have been constructed. Thanks for the
    Message 1 of 9 , Jun 30, 2007
      Hi Jo,
      Thanks again for the interest.
      I beleive i have the timings figured out but wont know until the
      chassis and legs have been constructed. Thanks for the links, I
      haven't read through these yet but the paper from Fraunhofer Institut
      was where i got about 80-85 percent of my information.
      Actually the hardest part to this point has been the muxes as they
      dont simply affect legs down one side, some sensors need to affect
      all legs, some affect legs down one side and other sensors affect leg
      groups (i.e. left4 right3 left2 right1 or right4 left3 right2 left1).
      Deciding which sensor to use for the bots "Lift Legs Higher" mode is
      another problem im still looking at but probably wont be able to do
      much until the legs and chassis are built.
      Another thing I plan on doing because the body will be covered with
      Litho plate (aluminium) is to use a couple of plates as the antenna
      for wilfs E-field detectors and use another plate for a touch
      on/touch off switch for the power supply.
      As for the processor again thanks for the link. I have been in the
      shadows in the Picaxe forum for a while. The thing is I don't know
      how the picaxe base program takes up the PiC and if it looses any
      processing or storage because of this. The Picaxe would be my first
      choice for ease of programming and although it (mainly) only has to
      influence the beam circuits I intend to use the rider to control the
      tail and arms (I dont plan on anything too complex for the arms and
      tail at this point, I just want them to move).I also need to figure
      out how best to use QTC Pills or Pipe for semsors.
      Looking forward to your K9 project being completed and I hope my
      scorpions body is half as good as your K9's.
      Have to go to work now but I'll keep you updated on new developements.

      Jim
      Jo Charles" wrote:

      Blimey, Jim, you've got your work cut out for you! This is very
      interesting work; the replication of the gaits will certainly
      mean a lot of thinking, and fine-tuning.

      I assume you know of these pages, but I'll include them nonetheless:

      http://www.oricomtech.com/projects/legs.htm#Simp2

      http://www.oricomtech.com/projects/leg-time.htm

      A very interesting read.

      On the processor side, I don't know what experience you have
      (I have practically zero), but you might want to look at the
      Picaxe range. They are very easy to program using a BASIC
      variant, and the programming interface is essentially a three
      wire serial connection to your PC, and two resistors. Programming
      software is a free download. Friendly and knowledgeable
      forum, too.

      http://www.rev-ed.co.uk/picaxe/

      Thanks for sharing the details. All I can do is wish you luck!
      Please keep us informed of your progress.

      Jo
    • Joseph Charles
      Hi Jim, The Picaxes certainly aren t as powerful or quick as a raw Pic or AVR, as the preprogrammed interpreter takes up space and limits the speed, but their
      Message 2 of 9 , Jul 2 4:15 AM
        Hi Jim,

        The Picaxes certainly aren't as powerful or quick as a raw
        Pic or AVR, as the preprogrammed interpreter takes up space
        and limits the speed, but their ease of use and low cost
        (not much more than the cost of the raw Pic) more than makes
        up for that in a lot of applications.

        There have been additions to the range recently with increased
        capabilities.

        I'm using an 18A (based on the Microchip PIC 16F819) to control
        the LCD in K9. I know bugger all about this, but had data readings
        up on the LCD in couple of hours, including reading datasheets and
        setting up the breadboard. It actually might have been faster than
        that! Trying with a raw Pic, and my limited knowledge, I could still
        be here next year trying to do it.

        I'm using a transmitter and receiver from an RC car
        for radio control, but could quite easily make my own, more
        powerful, control with a couple of cheap 8 pin picaxes and a
        433MHz Tx/Rx set.

        Their low cost makes using a few of them for distributed control
        quite a viable proposition.

        Anyway, enough of the advertising, but I really am sold on these
        little chips.

        Still love my analogue 'bots, though!

        Jo


        --- In beam@yahoogroups.com, "JIM" <lightninjim1@...> wrote:

        > The thing is I don't know how the picaxe base program takes up
        > the PiC and if it loses any processing or storage because of this.
      • JIM
        Hi Jo, currently I m undecided on a path to follow: I like the idea of their simple programming language but I think a decent compiler could do just as good a
        Message 3 of 9 , Jul 2 11:14 AM
          Hi Jo,
          currently I'm undecided on a path to follow: I like the idea of
          their simple programming language but I think a decent compiler could
          do just as good a job and it would save the sacrifice in speed (not
          too important as the Picaxe is more than quick enough) and memory.

          Many moons ago during my apprenticeship I had to learn C and Hex in
          order to retrive data from corrupted memory. Like I've already stated
          I hate debugging programs especially in either of these languages and
          so I may opt for the Pic/Compiler route or I may opt for the Picaxe
          route.
          For now I'm going to stick to working on my scorpion in beam form
          (between other projects like frog etc.) and try to prove to myself I
          haven't lost the plot altogether.
          After studying a leg I can tell it's not got the right articulation
          or the correct angles in relation to the servo mounting points in
          order to work correctly. Back to the drawing board again :C
          >
          In beam@yahoogroups.com, Jo wrote:
          > The Picaxes certainly aren't as powerful or quick as a raw
          > Pic or AVR, as the preprogrammed interpreter takes up space
          > and limits the speed, but their ease of use and low cost
          > (not much more than the cost of the raw Pic) more than makes
          > up for that in a lot of applications.
          >
          > Still love my analogue 'bots, though!
          >
          > Jo

          Yeah I know. They've grown on me too;D

          Jim
        • Joseph Charles
          You re obviously far more experienced than me in these matters, Jim, so I ll spare you my advice! :) I ve been playing with a 16F628a Pic for the last few
          Message 4 of 9 , Jul 3 3:38 AM
            You're obviously far more experienced than me in these
            matters, Jim, so I'll spare you my advice! :)

            I've been playing with a 16F628a Pic for the last few months,
            in between other projects (not all robotics!) and it's quite
            good fun. Assembler wasn't as hard to get to grips with as I
            thought it would be, but I'm only flashing LEDs and getting
            them to run in sequence, etc. Much more to learn, yet! I'm
            also teaching myself C from a great big book entitled, "Teach
            Yourself C in 21 Days". It seems to be taking me a little bit
            longer than that! Still, lots of fun trying.

            Hooroo,

            Jo

            --- In beam@yahoogroups.com, "JIM" <lightninjim1@...> wrote:


            > Many moons ago during my apprenticeship I had to learn C and Hex in
            > order to retrieve data from corrupted memory.
          • JIM
            ... That depends upon perspective ;) and advice is always appreciated. ... Debugging Assembler is a bleedin nightmare and it took me over two years to become
            Message 5 of 9 , Jul 3 1:37 PM
              --- In beam@yahoogroups.com, "Joseph Charles" <jodicalhon@...> wrote:
              >
              > "You're obviously far more experienced than me in these
              > matters, Jim, so I'll spare you my advice! :) "

              That depends upon perspective ;) and advice is always appreciated.

              > "I've been playing with a 16F628a Pic for the last few months,
              > in between other projects (not all robotics!) and it's quite
              > good fun. Assembler wasn't as hard to get to grips with as I
              > thought it would be, but I'm only flashing LEDs and getting
              > them to run in sequence, etc. Much more to learn, yet! I'm
              > also teaching myself C from a great big book entitled, "Teach
              > Yourself C in 21 Days". It seems to be taking me a little bit
              > longer than that! Still, lots of fun trying."

              Debugging Assembler is a bleedin nightmare and it took me over two
              years to become barely competent. I still seek advice, guidance and
              assistance from one of my dads friends everytime I go near it. The
              same applies to C although I think it's a bit easier to debug. If I
              use a raw Pic I was thinking of writing in basic and using a compiler
              to convert it to C. Although after reading what I've just wrote that
              would seem to defeat the purpose of using a raw Pic.
              Ye God's I'm getting confused easily these days. I'll look closely at
              this subject nearer the time.
              As for the book, when I was learning I remember reading a book
              called "C The Easy Way" (I think). I can tell you the book would
              probably have been easier to physically digest than it was mentally
              and if memory serves correctly I believe it was about as thick as the
              yellow pages (Do you have them in Oz??)

              Jim
            • JIM
              Just a bit of an update. I ve simplified the design slightly. But the terms simplified circuit and simplified mechanics are oxymorons. Im up to about 40 chips
              Message 6 of 9 , Jul 18 12:19 PM
                Just a bit of an update.

                I've simplified the design slightly. But the terms simplified circuit
                and simplified mechanics are oxymorons. Im up to about 40 chips and 35
                transistors, without sensors and complete power distribution systems.
                I've reduced the movemnt by 1 DOF on each leg too.
                Everything seems to be working ok at the moment but its not finished.
                I've tested most circuits individually but none have been tested
                together as yet.
                I can see a very dim candle at the end of the tunnel but its still a
                long long long way off :(

                Jim
              • Joseph Charles
                Keep goin , Jim! Good luck. Jo
                Message 7 of 9 , Jul 19 6:07 AM
                  Keep goin', Jim! Good luck.

                  Jo

                  --- In beam@yahoogroups.com, "JIM" <lightninjim1@...> wrote:

                  > I can see a very dim candle at the end of the tunnel but its still a
                  > long long long way off :(
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