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I'm new - I want to build me a DC2

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  • sq_ocelot
    Hello, everyone. I only found out about the digicomp II pretty recently, and I must say that I am fascinated by it. So much so that I ve decided I would like
    Message 1 of 21 , Nov 12, 2009
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      Hello, everyone. I only found out about the digicomp II pretty recently, and I must say that I am fascinated by it. So much so that I've decided I would like to build my own.

      I probably won''t be doing anything construction-wise for a month or so, until I go on winter break from school, but at that point I'll have plenty of time to work on it.

      Here as some initial thought on how I'd like to do it:

      I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks, and other stuff like that, powered by marbles. I thought the LEGO one that first drew me into this fascinating contraption was pretty awesome, but I don't have the resources to use that kind of material. I have some preliminary ideas for gate design and such, but they're not developed enough to bother detailing them here.

      Also, I had the notion to put the second layer next to the first instead of behind it, with channels for marbles connecting the two. I feel like if the second layer was behind the first, it would be blocked and so it wouldn't be as fun or interesting to watch. If they were placed side by side, then I would have to employ a wire or something connecting the gates so that a flip of one also affects the other.

      I'm coming up with these ideas using the manual and the patent as guides, and I don't imagine I'll really know how I'm going to work everything until I start really working on it in a month or so, but I thought I'd get this out there in case anyone has any comments or advice, or anything else to share.

      Anyone?
    • Bob S.
      Search the messages for enhancements . For communications from the inventor of Digi-Comp II, search for godfreyjohnt . I ve been playing with single plane
      Message 2 of 21 , Nov 13, 2009
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        Search the messages for "enhancements". For communications from the
        inventor of Digi-Comp II, search for "godfreyjohnt".

        I've been playing with single plane ideas for some time. Contact me
        directly if you want: PasoDad at aol.com.

        -Bob S.


        -----Original Message-----

        I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks, and
        other stuff like that, powered by marbles.

        Also, I had the notion to put the second layer next to the first instead of
        behind it, with channels for marbles connecting the two.

        I thought I'd get this out there in case anyone has any comments or advice,
        or anything else to share.

        Anyone?
      • bdavis61856
        ... I understand - the LEGO one took a lot of materials, and is big and bulky, and limiting myself to pure LEGO made it very difficult to reliably flip gates
        Message 3 of 21 , Nov 13, 2009
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          sq_ocelot wrote:

          > I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks,
          > and other stuff like that, powered by marbles. I thought the LEGO
          > one that first drew me into this fascinating contraption was pretty
          > awesome, but I don't have the resources to use that kind of material.

          I understand - the LEGO one took a lot of materials, and is big and bulky, and limiting myself to "pure LEGO" made it very difficult to reliably flip gates (the soccer balls are very light). However, it's a great way to prototype.

          Ideally I want to make a DCII & Dr Nim out of wood: take a thick board and a router to do all the channels, with small pins pivoting the gates. The gates themselves could be made out of wood as well, but I'd probably go with plastic (clear lucite or acrylic would look good, and you could color them to suit, or have them cover and obscure numbers written under them). The denser the balls, the easier it is to get them to throw gates, so I'd use marbles, or even ball bearings... but every time you change the size or weight, you'll change the way the gates act as well, so expect some tuning.

          As to a quicker cheaper way (the LEGO one was about $700 if I remember), you might use pegboard, allowing you to adjust supports for the ramps and guides, as well as a mounting place for the gates. It will be *big*... but start small. When I built it out of LEGO, I did it as a series of repeated units (almost all the accumulator registers are identical, for instance), so I built a couple and cascaded them, adjusting until it was working well, and then stretched it to the entire thing. I'd suggest something fairly stiff for the backing... probably not cardboard, unless it's supported by wood or similar behind. Popcicle or kraft sticks sound like a possibility for guides, or even disposable drinking straws for a 1st attempt... it the gates that are a bigger issue I suspect. For a long calculation, DCII has to throw a *lot* of gates... and if even one flips wrong, the result is garbage.

          > I have some preliminary ideas for gate design and such, but they're
          > not developed enough to bother detailing them here.

          I'd still love to hear them.

          > Also, I had the notion to put the second layer next to the first
          > instead of behind it, with channels for marbles connecting the
          > two.

          I agree it would be neater if you could see that. I actually tried what you mention for the LEGO version, but the friction of moving two gates on two pivots with a bit of string between them was much too great... but I was limited to those light balls. With heavier balls, this might be doable, but I've not figured out the design this way as yet. BTW, on the LEGO version the toughest thing to get correct was the ball release, which is the only place I used string to activate something. It's slightly tricky to get a ball to reliably release another of the same mass.

          > I'm coming up with these ideas using the manual and the patent as
          > guides, and I don't imagine I'll really know how I'm going to work
          > everything until I start really working on it in a month or so...

          Someone here (Bob?) had some photographs of the bottom layer that proved critical - while I could see how it was supposed to work, sort of, from the patent, the picture really helped.

          And any further discussion you want to have on this, you can certainly contact me off-group as well (brdavis@...), but I'd really appreciate it if you did as much as possible "out in the open" on the group, so the rest of us can live (& learn!) vicariously :).

          --
          Brian Davis
        • Kurt Kammeyer
          In my mind, the DigiComp I is the only true mechanical computer. I bought one of the new $65 cardboard ones a couple years ago and assembled it, but it
          Message 4 of 21 , Nov 13, 2009
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            In my mind, the DigiComp I is the only "true" mechanical computer. I bought one of the new $65 cardboard ones a couple years ago and assembled it, but it doesn't work nearly as smoothly as the original plastic ones (I had one back in the late 60's, and I still kick myself for giving it away to a friend).

            I have been thinking of using my cardboard DigiComp as a template to make a DigiComp IV. It would work just like the DigiComp I, except I would add an extra row and column to the matrix so it would have a 4-bit memory, allowing it to count up to 15 instead of just 7. Could the Harvard Mark I be far behind?

            I think the best material for this kind of project is plexiglass. If you have a router table you can easily trim the plastic to any shape you want, and it looks really nice too.

            Kurt Kammeyer

            --- On Fri, 11/13/09, bdavis61856 <brdavis@...> wrote:

            From: bdavis61856 <brdavis@...>
            Subject: [Friends of DigiComp] Re: I'm new - I want to build me a DC2
            To: friendsofdigicomp@yahoogroups.com
            Date: Friday, November 13, 2009, 1:49 PM







             









            sq_ocelot wrote:



            > I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks,

            > and other stuff like that, powered by marbles. I thought the LEGO

            > one that first drew me into this fascinating contraption was pretty

            > awesome, but I don't have the resources to use that kind of material.



            I understand - the LEGO one took a lot of materials, and is big and bulky, and limiting myself to "pure LEGO" made it very difficult to reliably flip gates (the soccer balls are very light). However, it's a great way to prototype.



            Ideally I want to make a DCII & Dr Nim out of wood: take a thick board and a router to do all the channels, with small pins pivoting the gates. The gates themselves could be made out of wood as well, but I'd probably go with plastic (clear lucite or acrylic would look good, and you could color them to suit, or have them cover and obscure numbers written under them). The denser the balls, the easier it is to get them to throw gates, so I'd use marbles, or even ball bearings... but every time you change the size or weight, you'll change the way the gates act as well, so expect some tuning.



            As to a quicker cheaper way (the LEGO one was about $700 if I remember), you might use pegboard, allowing you to adjust supports for the ramps and guides, as well as a mounting place for the gates. It will be *big*... but start small. When I built it out of LEGO, I did it as a series of repeated units (almost all the accumulator registers are identical, for instance), so I built a couple and cascaded them, adjusting until it was working well, and then stretched it to the entire thing. I'd suggest something fairly stiff for the backing... probably not cardboard, unless it's supported by wood or similar behind. Popcicle or kraft sticks sound like a possibility for guides, or even disposable drinking straws for a 1st attempt... it the gates that are a bigger issue I suspect. For a long calculation, DCII has to throw a *lot* of gates... and if even one flips wrong, the result is garbage.



            > I have some preliminary ideas for gate design and such, but they're

            > not developed enough to bother detailing them here.



            I'd still love to hear them.



            > Also, I had the notion to put the second layer next to the first

            > instead of behind it, with channels for marbles connecting the

            > two.



            I agree it would be neater if you could see that. I actually tried what you mention for the LEGO version, but the friction of moving two gates on two pivots with a bit of string between them was much too great... but I was limited to those light balls. With heavier balls, this might be doable, but I've not figured out the design this way as yet. BTW, on the LEGO version the toughest thing to get correct was the ball release, which is the only place I used string to activate something. It's slightly tricky to get a ball to reliably release another of the same mass.



            > I'm coming up with these ideas using the manual and the patent as

            > guides, and I don't imagine I'll really know how I'm going to work

            > everything until I start really working on it in a month or so...



            Someone here (Bob?) had some photographs of the bottom layer that proved critical - while I could see how it was supposed to work, sort of, from the patent, the picture really helped.



            And any further discussion you want to have on this, you can certainly contact me off-group as well (brdavis@iusb. edu), but I'd really appreciate it if you did as much as possible "out in the open" on the group, so the rest of us can live (& learn!) vicariously :).



            --

            Brian Davis

























            [Non-text portions of this message have been removed]
          • Kurt Kammeyer
            In my mind, the DigiComp I is the only true mechanical computer. I bought one of the new $65 cardboard ones a couple years ago and assembled it, but it
            Message 5 of 21 , Nov 13, 2009
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              In my mind, the DigiComp I is the only "true" mechanical computer. I
              bought one of the new $65 cardboard ones a couple years ago and
              assembled it, but it doesn't work nearly as smoothly as the original
              plastic ones (I had one back in the late 60's, and I still kick myself
              for giving it away to a friend).

              I
              have been thinking of using my cardboard DigiComp as a template to make
              a DigiComp IV. It would work just like the DigiComp I, except I would
              add an extra row and column to the matrix so it would have a 4-bit
              memory, allowing it to count up to 15 instead of just 7. Could the Harvard Mark I be far behind?

              I
              think the best material for this kind of project is plexiglass. If you
              have a router table you can easily trim the plastic to any shape you
              want, and it looks really nice too.

              Kurt Kammeyer

              --- On Fri, 11/13/09, sq_ocelot <no_reply@yahoogroups.com> wrote:

              From: sq_ocelot <no_reply@yahoogroups.com>
              Subject: [Friends of DigiComp] I'm new - I want to build me a DC2
              To: friendsofdigicomp@yahoogroups.com
              Date: Friday, November 13, 2009, 2:33 AM







               









              Hello, everyone. I only found out about the digicomp II pretty recently, and I must say that I am fascinated by it. So much so that I've decided I would like to build my own.



              I probably won''t be doing anything construction- wise for a month or so, until I go on winter break from school, but at that point I'll have plenty of time to work on it.



              Here as some initial thought on how I'd like to do it:



              I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks, and other stuff like that, powered by marbles. I thought the LEGO one that first drew me into this fascinating contraption was pretty awesome, but I don't have the resources to use that kind of material. I have some preliminary ideas for gate design and such, but they're not developed enough to bother detailing them here.



              Also, I had the notion to put the second layer next to the first instead of behind it, with channels for marbles connecting the two. I feel like if the second layer was behind the first, it would be blocked and so it wouldn't be as fun or interesting to watch. If they were placed side by side, then I would have to employ a wire or something connecting the gates so that a flip of one also affects the other.



              I'm coming up with these ideas using the manual and the patent as guides, and I don't imagine I'll really know how I'm going to work everything until I start really working on it in a month or so, but I thought I'd get this out there in case anyone has any comments or advice, or anything else to share.



              Anyone?

























              [Non-text portions of this message have been removed]
            • Bob S.
              ... Whoa there pardner! Leaving out Babbage s Engines, Zuse s Z1, adding machines, old gas pumps and all mechanical analog computers; I suppose you re only
              Message 6 of 21 , Nov 13, 2009
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                > In my mind, the DigiComp I is the only "true" mechanical computer.

                Whoa there pardner!

                Leaving out Babbage's Engines, Zuse's Z1, adding machines, old gas pumps and all mechanical analog computers; I suppose you're only comparing DC1 to DC2. Neither actually qualifies as a computer but the DC2 has greater similarity. It even includes a programming language (DIGITRAN).

                That said, I think the DC1 was the more interesting machine. Too bad it wasn't represented as what it truly was -- a Programmable Logic Device (PLD).

                -Bob S.
              • sq_ocelot
                ... Well, I m a college student without a whole lot of funds to work with, and I m trying to do this on as small a budget as possible, so I m gonna go ahead
                Message 7 of 21 , Nov 13, 2009
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                  --- In friendsofdigicomp@yahoogroups.com, "bdavis61856" <brdavis@...> wrote:
                  >
                  > sq_ocelot wrote:
                  >
                  > > I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks,
                  > > and other stuff like that, powered by marbles.

                  >I'd suggest something fairly stiff for the backing... probably not cardboard, unless it's supported by wood or similar behind. Popcicle or kraft sticks sound like a possibility for guides, or even disposable drinking straws for a 1st attempt... it the gates that are a bigger issue I suspect. For a long calculation, DCII has to throw a *lot* of gates... and if even one flips wrong, the result is garbage.
                  >

                  Well, I'm a college student without a whole lot of funds to work with, and I'm trying to do this on as small a budget as possible, so I'm gonna go ahead and use cardboard from around my house (probably to be reinforced with wooden skewers or something like that) and not out of wood that I'd have to go buy. I've actually started some construction (just basic surface and guides stuff; I was too excited to wait!), and I'll talk about that below.

                  > > I have some preliminary ideas for gate design and such, but they're
                  > > not developed enough to bother detailing them here.
                  >
                  > I'd still love to hear them.

                  Well, I've done some more considering since last night, and what I figured is I'd take three short pieces cut from a popsicle stick and arrange them in an upside-down Y shape for the flip-flops, reinforcing them from the front with other pieces of stick glued on (this would serve both to help the Y retain its shape and to keep balls from falling out the front -- though I have no idea if the latter is going to be an issue). Right between the 'legs' of the Y, I would glue a wooden skewer (cut to an appropriate length), which would be stuck through the cardboard and serve as the pivot for the gate.

                  Other gates would be similar, but shaped differently depending on what kind it is (like, just a line, or a checkmark-shape for the half flip-flops, etc.)

                  >
                  > > Also, I had the notion to put the second layer next to the first
                  > > instead of behind it, with channels for marbles connecting the
                  > > two.
                  >

                  So, the basic structure for the design that I'm thinking about involves one large sheet of cardboard to serve as the back of the entire structure, with two raised panels, one being the top layer of the original, the other being the lower layer. The two panels would be side-by-side, with a few inches gap between. Where the holes in the front appear, there would be two wooden skewers close enough to carry the marble right behind the hole, but angled outwards so that the marble drops through them onto a rail (which I'm thinking would just be another wooden skewer set away from the back piece of cardboard a bit, so that the marble would roll between the skewer and the back wall), then the marble would roll out onto the second layer via a similar (but reversed) mechanism (which I haven't thought entirely through yet, I don't know where I'll have to throw up walls so that the marble doesn't fall out or anything, but I'll see how it goes when I construct that part), then once it does it's stuff, it would go back to the original panel by way of the same kind of thing.

                  About the gate design (which I explained above), I would stick the skewer through both layers of cardboard to keep it from going out of line. Then, I thought that to make a movement in a switch on the second layer transfer to the first (and vice versa) where it's supposed to, I could put a gear or a wheel on those skewers and connect them with a loop of string or elastic, so that one turns the other (if I glue the string in a single dot on the 'outside' part of each wheel, would that make the wheels guaranteed to turn each other? I feel like it would, but I'm not entirely sure).

                  Like I said, I've begun some preliminary construction, which simple included finding a good piece of cardboard for the top-level panel, and tracing all the guides from the figure in the manual onto it, and hot-gluing (which I've decided will be my primary binding agent, it works surprisingly well, better even than I thought it would) some popsicle sticks onto those lines that I'm sure are correct and don't need messing with to make them work. Is that a good idea, to just copy the design of that figure from the manual onto the cardboard, or will it turn out to be problematic? I feel like it should be fine, but then again I'm a total novice at all of this and I have very little clue.

                  I've got a question, though, about the holes in the front panel, though: how many are there, and where are they? The patent shows, I believe, six (excluding the return ramp), one behind each of the four M registers, and then two at the top (whose purpose I don't entirely understand, could someone explain please?). The figure from the manual doesn't show any, but I'm guessing that the four behind the Ms are still there just obscured, but I can't see where those two higher holes are supposed to be. Then, in the pictures on this group of the wooden DC2, I see six holes again, but only one where the two pictured on the patent are supposed to be, and another one that is somewhere directly above the four for the Ms. I'm a little confused, so if someone could explain all this that would be great.
                • Bob S.
                  ... OK -- Pictures of the boards with most parts removed are now in the Digi-Comp II folder of the group s pictures. There is also a folder for a wooden DCII
                  Message 8 of 21 , Nov 13, 2009
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                    > Someone here (Bob?) had some photographs of the bottom layer
                    > that proved critical - while I could see how it was supposed to
                    > work, sort of, from the patent, the picture really helped.

                    OK -- Pictures of the boards with most parts removed are now in the
                    Digi-Comp II folder of the group's pictures. There is also a folder for a
                    wooden DCII showing back details.

                    -Bob S.
                  • sq_ocelot
                    Thanks. Those board pictures help quite a bit in terms of getting my brain to picture how it all goes.
                    Message 9 of 21 , Nov 13, 2009
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                      Thanks. Those board pictures help quite a bit in terms of getting my brain to picture how it all goes.

                      --- In friendsofdigicomp@yahoogroups.com, "Bob S." <pasodad@...> wrote:
                      >
                      > > Someone here (Bob?) had some photographs of the bottom layer
                      > > that proved critical - while I could see how it was supposed to
                      > > work, sort of, from the patent, the picture really helped.
                      >
                      > OK -- Pictures of the boards with most parts removed are now in the
                      > Digi-Comp II folder of the group's pictures. There is also a folder for a
                      > wooden DCII showing back details.
                      >
                      > -Bob S.
                      >
                    • Bob S.
                      Friction of wood to cardboard may be a problem. If you glue the gate to the shaft, the shaft will rotate through two layers of cardboard. If you link two
                      Message 10 of 21 , Nov 13, 2009
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                        Friction of wood to cardboard may be a problem. If you glue the gate to the
                        shaft, the shaft will rotate through two layers of cardboard. If you link
                        two gates the friction doubles.

                        The original machine was nearly as compact as the gates would allow. The
                        metal shafts had little friction against the plastic bushings so little
                        torque was needed for rotation. Your gates may need to have longer arms or
                        use steel marbles (or both).

                        When linking reset gates to flip-flops, string will work because the action
                        only goes one direction. You'll need rigid links or pairs of string links
                        for an inverter function between gates.

                        IF you have the layers side to side, there is no need for marbles to cross
                        side to side. Most of the time a marble goes into a hole it is just to exit
                        without hitting gates on the way down.

                        Search for the enhancements suggested for inverting the accumulator.

                        Consider spending about $5 for a half or quarter sheet of 1/4" or thicker
                        Masonite. If you don't use the hidden layers you don't need the shaft to
                        rotate with the flip-flop. Use wire nails (brads?) and you have wood to
                        metal bearing surfaces, you don't need an extra layer to stabilize the
                        shafts, and your finished machine may last longer. Rent time on a drill
                        press (mooch from a friend) to get the pilot holes perpendicular to the
                        surface. Test ideas one element or group at a time on scrap.

                        My first marble adder used toothpicks and a shoebox. My second marble adder
                        used wire shafts (paperclips), sheet metal gates (food cans) soldered to the
                        shafts, and layers of Plexiglas to separate layers.

                        -Bob S.
                      • Neil Morrison
                        Try to add Teflon tape to rubbing parts. Neil From: Bob S. Friction of wood to cardboard may be a problem. If you glue the gate to the shaft, the shaft will
                        Message 11 of 21 , Nov 14, 2009
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                          Try to add Teflon tape to rubbing parts.

                          Neil



                          From: Bob S.

                          Friction of wood to cardboard may be a problem. If you glue the gate to the
                          shaft, the shaft will rotate through two layers of cardboard. If you link
                          two gates the friction doubles.



                          [Non-text portions of this message have been removed]
                        • bdavis61856
                          ... I d have to agree - neither is as yet a computer, but I can see ways of getting DC2 there a lot clearer than DC1 (and if I ever find the time, I ll try to
                          Message 12 of 21 , Nov 14, 2009
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                            "Bob S." <pasodad@...> wrote:

                            >> In my mind, the DigiComp I is the only "true" mechanical computer.
                            >
                            > Whoa there pardner!
                            >
                            > Leaving out Babbage's Engines, Zuse's Z1, adding machines, old gas
                            > pumps and all mechanical analog computers; I suppose you're only
                            > comparing DC1 to DC2. Neither actually qualifies as a computer but
                            > the DC2 has greater similarity.

                            I'd have to agree - neither is as yet a computer, but I can see ways of getting DC2 there a lot clearer than DC1 (and if I ever find the time, I'll try to move that way: it needs an addressable memory and a few very simple instructions with a decoder). There are a *lot* of amazing mechanical & analog computers; the Deutschs Museum in Munich actually has a section of a floor dedicated to such machines, I just wish I would have had enough time to really look through it when I was there this summer (I suspect a couple days might have been sufficient :) ).

                            Zuse's Z1 is one of the most inspired mechanical examples I've ever seen (on the web)... and I'd never even heard of it until this group.

                            --
                            Brian Davis
                          • sq_ocelot
                            ... Well I did some tests with this thing, and I found that if I poked a hole in the cardboard with a skewer, and then took the skewer out and made the hole
                            Message 13 of 21 , Nov 14, 2009
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                              --- In friendsofdigicomp@yahoogroups.com, "Neil Morrison" <neilsmorr@...> wrote:
                              >
                              > Try to add Teflon tape to rubbing parts.
                              >
                              > Neil
                              >
                              >
                              >
                              > From: Bob S.
                              >
                              > Friction of wood to cardboard may be a problem. If you glue the gate to the
                              > shaft, the shaft will rotate through two layers of cardboard. If you link
                              > two gates the friction doubles.
                              >
                              >
                              >
                              > [Non-text portions of this message have been removed]
                              >


                              Well I did some tests with this thing, and I found that if I poked a hole in the cardboard with a skewer, and then took the skewer out and made the hole just a tiny big bigger with an x-acto knife, the skewer could spin quite freely in it (I tested it through two layers, too, and it still worked great). So, I think that's what I'm gonna do.

                              Also, I understand more about how the two-layered thing works, and I feel like my initial plan to put them side by side would be far more trouble than it would be worth. So, I still think I'm going to do it like the real thing, and put the second layer behind the first. I would still like some explanation of what the two highest holes on the board do, though, if someone would please enlighten me.

                              And about all the crazy materials that are being suggested to me, thanks everyone, but I'm only doing this for fun. I know it may not last forever, or parts of it may work less than perfectly, but I'm okay with that. I'm going to use my cheap materials and methods, and I'm sure the result will still work just fine. Or at least, well enough for me. Maybe one day I'll make a better one. But I do appreciate the advice, and if any of you have more to add, then by all means let me know. Thanks.

                              --Andrew G.
                            • anthony2816@yahoo.com
                              ... If you re using two layers of corrugated cardboard, make sure one layer is 90 degrees to the other. Like plywood, it ll make it much stronger.
                              Message 14 of 21 , Nov 14, 2009
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                                > Also, I understand more about how the two-layered thing works

                                If you're using two layers of corrugated cardboard, make sure one layer
                                is 90 degrees to the other. Like plywood, it'll make it much stronger.
                              • Bob S.
                                ... board do, though, if someone would please enlighten me. Looking at photo of top board, highest hole is at the CLEAR switch. When the switch is on , a
                                Message 15 of 21 , Nov 15, 2009
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                                  > I would still like some explanation of what the two highest holes > on the
                                  board do, though, if someone would please enlighten me.

                                  Looking at photo of top board, highest hole is at the "CLEAR" switch. When
                                  the switch is "on", a marble drops through the hole to the lower level where
                                  it is guided to "half flip-flops" attached to each of the accumulator
                                  flip-flops to reset them all to zeros.

                                  Next hole is at CF-1 (complement flip-flop). When a marble drops through
                                  this hole to the lower level it is guided to flip-flops attached to each of
                                  the mode switches to toggle them between all left or all right. See page 33
                                  of the instruction manual for a description of the one's and two's
                                  complement operation.

                                  Best advice: Download and run the DigiComp II Emulator from our group's
                                  files section. You won't see the marble when it's on the lower level but
                                  you will see how it affects the top level.

                                  -Bob S.
                                • sq_ocelot
                                  Thanks. And yeah, I tried to download the emulator, but it wouldn t work for some reason.
                                  Message 16 of 21 , Nov 15, 2009
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                                    Thanks. And yeah, I tried to download the emulator, but it wouldn't work for some reason.
                                  • Conrad Bitzer
                                    hello Andrew, I built the wooden DC2 on the fotos.You can try other material but wood,for me its was the most easiest and cheapest way .Friction was only
                                    Message 17 of 21 , Nov 15, 2009
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                                      hello Andrew,
                                      I built the wooden DC2 on the fotos.You can try other material but wood,for me its was the most easiest and cheapest way .Friction was only particulary a problem,I worked with washers for distance and friction.
                                      A little difficulty were the dynamic effects of the balls and the gates, i had particulary to implement break elements. And it had been essential to adjust every path and dividor of the balls.
                                      The emulator is very helpful for understanding the DC2!
                                      Good luck for your work,
                                      yours Martin from Stuttgart Germany




                                      ________________________________
                                      From: sq_ocelot <no_reply@yahoogroups.com>
                                      To: friendsofdigicomp@yahoogroups.com
                                      Sent: Sun, November 15, 2009 2:06:21 PM
                                      Subject: Re: [Friends of DigiComp] I want to build me a DC2


                                      Thanks. And yeah, I tried to download the emulator, but it wouldn't work for some reason.



                                      ------------------------------------

                                      Yahoo! Groups Links






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                                    • Kurt Kammeyer
                                      You re right - I should have specified within the Digicomp line Kurt ... From: Bob S. Subject: RE: [Friends of DigiComp] I m new - I want
                                      Message 18 of 21 , Nov 15, 2009
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                                        You're right - I should have specified "within the Digicomp line"

                                        Kurt

                                        --- On Sat, 11/14/09, Bob S. <pasodad@...> wrote:

                                        From: Bob S. <pasodad@...>
                                        Subject: RE: [Friends of DigiComp] I'm new - I want to build me a DC2
                                        To: friendsofdigicomp@yahoogroups.com
                                        Date: Saturday, November 14, 2009, 2:36 AM







                                         









                                        > In my mind, the DigiComp I is the only "true" mechanical computer.



                                        Whoa there pardner!



                                        Leaving out Babbage's Engines, Zuse's Z1, adding machines, old gas pumps and all mechanical analog computers; I suppose you're only comparing DC1 to DC2. Neither actually qualifies as a computer but the DC2 has greater similarity. It even includes a programming language (DIGITRAN).



                                        That said, I think the DC1 was the more interesting machine. Too bad it wasn't represented as what it truly was -- a Programmable Logic Device (PLD).



                                        -Bob S.

























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                                      • Kurt Kammeyer
                                        I should have clarified - The only true DigiComp computer . The DC1 is really a brilliant design. I m thinking of building a DigiComp IV by increasing the
                                        Message 19 of 21 , Nov 15, 2009
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                                          I should have clarified - "The only true DigiComp computer". The DC1 is really a brilliant design. I'm thinking of building a DigiComp IV by increasing the width and height of the matrix to 4x4, so it can count up to 15 instead of just 7.

                                          Kurt

                                          --- On Sun, 11/15/09, bdavis61856 <brdavis@...> wrote:

                                          From: bdavis61856 <brdavis@...>
                                          Subject: Re: [Friends of DigiComp] I'm new - I want to build me a DC2
                                          To: friendsofdigicomp@yahoogroups.com
                                          Date: Sunday, November 15, 2009, 1:59 AM







                                           









                                          "Bob S." <pasodad@... > wrote:



                                          >> In my mind, the DigiComp I is the only "true" mechanical computer.

                                          >

                                          > Whoa there pardner!

                                          >

                                          > Leaving out Babbage's Engines, Zuse's Z1, adding machines, old gas

                                          > pumps and all mechanical analog computers; I suppose you're only

                                          > comparing DC1 to DC2. Neither actually qualifies as a computer but

                                          > the DC2 has greater similarity.



                                          I'd have to agree - neither is as yet a computer, but I can see ways of getting DC2 there a lot clearer than DC1 (and if I ever find the time, I'll try to move that way: it needs an addressable memory and a few very simple instructions with a decoder). There are a *lot* of amazing mechanical & analog computers; the Deutschs Museum in Munich actually has a section of a floor dedicated to such machines, I just wish I would have had enough time to really look through it when I was there this summer (I suspect a couple days might have been sufficient :) ).



                                          Zuse's Z1 is one of the most inspired mechanical examples I've ever seen (on the web)... and I'd never even heard of it until this group.



                                          --

                                          Brian Davis

























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                                        • Bob S.
                                          Eric Uhrhane designed a computer to use elements similar to those in DCII. He wrote his own simulator (no animation) and has much of the simulation done. This
                                          Message 20 of 21 , Nov 16, 2009
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                                            Eric Uhrhane designed a computer to use elements similar to those in DCII. He wrote his own simulator (no animation) and has much of the simulation done.

                                            This is an ambitious project with 30 instructions and a hardware multiplier. This is a spare time project for a very busy fellow. It started in 2005 and the most recent entry was May 2009.

                                            http://ballcomputer.blogspot.com/

                                            We exchanged a couple of emails but I guess I scared him off.

                                            -Bob S.
                                          • WILLIAM
                                            You can use small or large metal paper clips with one end pointing down to bend into flip-flops. Bill Kustes
                                            Message 21 of 21 , Dec 15, 2009
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                                              You can use small or large metal paper clips with one end pointing down to bend into flip-flops.
                                              Bill Kustes

                                              --- In friendsofdigicomp@yahoogroups.com, sq_ocelot <no_reply@...> wrote:
                                              >
                                              >
                                              >
                                              > --- In friendsofdigicomp@yahoogroups.com, "bdavis61856" <brdavis@> wrote:
                                              > >
                                              > > sq_ocelot wrote:
                                              > >
                                              > > > I'm thinking I'll do it out of cardboard, popsicle sticks, toothpicks,
                                              > > > and other stuff like that, powered by marbles.
                                              >
                                              > >I'd suggest something fairly stiff for the backing... probably not cardboard, unless it's supported by wood or similar behind. Popcicle or kraft sticks sound like a possibility for guides, or even disposable drinking straws for a 1st attempt... it the gates that are a bigger issue I suspect. For a long calculation, DCII has to throw a *lot* of gates... and if even one flips wrong, the result is garbage.
                                              > >
                                              >
                                              > Well, I'm a college student without a whole lot of funds to work with, and I'm trying to do this on as small a budget as possible, so I'm gonna go ahead and use cardboard from around my house (probably to be reinforced with wooden skewers or something like that) and not out of wood that I'd have to go buy. I've actually started some construction (just basic surface and guides stuff; I was too excited to wait!), and I'll talk about that below.
                                              >
                                              > > > I have some preliminary ideas for gate design and such, but they're
                                              > > > not developed enough to bother detailing them here.
                                              > >
                                              > > I'd still love to hear them.
                                              >
                                              > Well, I've done some more considering since last night, and what I figured is I'd take three short pieces cut from a popsicle stick and arrange them in an upside-down Y shape for the flip-flops, reinforcing them from the front with other pieces of stick glued on (this would serve both to help the Y retain its shape and to keep balls from falling out the front -- though I have no idea if the latter is going to be an issue). Right between the 'legs' of the Y, I would glue a wooden skewer (cut to an appropriate length), which would be stuck through the cardboard and serve as the pivot for the gate.
                                              >
                                              > Other gates would be similar, but shaped differently depending on what kind it is (like, just a line, or a checkmark-shape for the half flip-flops, etc.)
                                              >
                                              > >
                                              > > > Also, I had the notion to put the second layer next to the first
                                              > > > instead of behind it, with channels for marbles connecting the
                                              > > > two.
                                              > >
                                              >
                                              > So, the basic structure for the design that I'm thinking about involves one large sheet of cardboard to serve as the back of the entire structure, with two raised panels, one being the top layer of the original, the other being the lower layer. The two panels would be side-by-side, with a few inches gap between. Where the holes in the front appear, there would be two wooden skewers close enough to carry the marble right behind the hole, but angled outwards so that the marble drops through them onto a rail (which I'm thinking would just be another wooden skewer set away from the back piece of cardboard a bit, so that the marble would roll between the skewer and the back wall), then the marble would roll out onto the second layer via a similar (but reversed) mechanism (which I haven't thought entirely through yet, I don't know where I'll have to throw up walls so that the marble doesn't fall out or anything, but I'll see how it goes when I construct that part), then once it does it's stuff, it would go back to the original panel by way of the same kind of thing.
                                              >
                                              > About the gate design (which I explained above), I would stick the skewer through both layers of cardboard to keep it from going out of line. Then, I thought that to make a movement in a switch on the second layer transfer to the first (and vice versa) where it's supposed to, I could put a gear or a wheel on those skewers and connect them with a loop of string or elastic, so that one turns the other (if I glue the string in a single dot on the 'outside' part of each wheel, would that make the wheels guaranteed to turn each other? I feel like it would, but I'm not entirely sure).
                                              >
                                              > Like I said, I've begun some preliminary construction, which simple included finding a good piece of cardboard for the top-level panel, and tracing all the guides from the figure in the manual onto it, and hot-gluing (which I've decided will be my primary binding agent, it works surprisingly well, better even than I thought it would) some popsicle sticks onto those lines that I'm sure are correct and don't need messing with to make them work. Is that a good idea, to just copy the design of that figure from the manual onto the cardboard, or will it turn out to be problematic? I feel like it should be fine, but then again I'm a total novice at all of this and I have very little clue.
                                              >
                                              > I've got a question, though, about the holes in the front panel, though: how many are there, and where are they? The patent shows, I believe, six (excluding the return ramp), one behind each of the four M registers, and then two at the top (whose purpose I don't entirely understand, could someone explain please?). The figure from the manual doesn't show any, but I'm guessing that the four behind the Ms are still there just obscured, but I can't see where those two higher holes are supposed to be. Then, in the pictures on this group of the wooden DC2, I see six holes again, but only one where the two pictured on the patent are supposed to be, and another one that is somewhere directly above the four for the Ms. I'm a little confused, so if someone could explain all this that would be great.
                                              >
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