Robert Cailliau

Eurobricks Vassals
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Everything posted by Robert Cailliau

  1. Robert Cailliau

    Duplo Trains discussion

    It is a funny piece in more ways than one. It follows the old style, where they could not be put on top of bricks or plates because the coupling bits went down too far, getting in the way of the studs of the plates or bricks. Therefore they cannot be used to build on supported slopes or bridges, only laid out flat. You may wish to explore /L/Lego/Duplo/Train/Rails/Dimensions/ (on first visit you may have to click the "Englsih" button and then reload the link; I'll change that asap) So who wrote the track planning app? Can I get it? BTW, also note this: /M/Mathematics/APR/Description/
  2. Robert Cailliau

    Duplo Trains discussion

    Goede middag Edge_nl, For some reason I did not see your thank-you (thanks!) nor your very interesting 3D printing suggestions for more rail formats. Sorry for that, I just saw them this morning. And yes, a topic for 3D printing of compatible parts is a very good idea. I have a printer (Ultimaker-2), but the grandchildren have outgrown Duplo… Does a 3D group of topics not already exist? I have not looked. In any case, Duplo rails do not require the same precision in 3D printing as standard Lego pieces do. Unless parhaps for sticking to Duplo bricks. Thanks! (I've got OpenSCAD too)
  3. Robert Cailliau

    Duplo Trains discussion

    There you go: So it's three studs by four. These bits are useful to close some layouts with tracks at angles other than 90º. However, they do not stick to plates or blocks and there is quite a lot of play. The answer then is: 3x8=24, so 8 small ones will have the same length as 3 standard ones. Nothing in between.
  4. Yes, "someday" is also on many of my lists… ;-) Anyway, perhaps I should research techniques for getting 0.5 unit distances with the studless beams. Another "someday": publish a list of parts that would be useful but do not exist. Many of them are connectors.
  5. I did not find this set so very good. The pneumatics don't really work as well as I would expect, probably due to the not so very good compressor, but also due to the hoses to the pistons. The gearbox that drives it all is complex and has a lot of friction. The geometry of the steering is good though. But I would certainly not rate it as the best Technics set ever. There are some excellent sets, and some that are rather disappointing. Admittedly, it's very difficult to make Technics sets that work well and in the end are also good-looking. The Arocs gets 5 out of 10 from me. The bucket wheel excavator (42055) is the best one I have built: everything works well and all dimensioning is correct (*) Then there is the whole issue of creativity: building a mechanism with the new-fashion beams that have no studs is sometimes frustrating, as there is no easy way of getting a half-unit offset. (**) But that has nothing to do with this particular set, it's a general remark. Robert. (*) the ferris wheel, 10247, has Pythagorean triangles that are wrong, one of them has a side that is off by 2.77mm (implemented: 132mm, Pythagoras: 129.2308mm); there are several Pythagorean triangles in the bucket wheel excavator but every one of them is correct! (If you need elucidation: a Pythagorean triangle is a right-angled triangle in which all sides have integer lengths, such as 3-4-5 (because 3x3+4x4=5x5), which is needed in the case of Lego where everything has to fit a discrete grid). (**) For example: making a 40 tooth wheel mesh with a 16 tooth is difficult: the axles need to be (40+16)/16 = 3.5 units apart. 3.5 is easy with the bricks with studs but not with the studless beams. I'm trying to design an astronomical clock that's as good as John Stouffer's (https://www.buildsteam.com/home/introduction-to-the-lego-astronomical-clock) but will sit on a table top instead of needing a large drop. Using only the "new" Technics "religion" of studless beams is very difficult, and I have actually given up and reverted to the beams with studs.
  6. Robert Cailliau

    Duplo Trains discussion

    I never see a reason why an old thread would necessarily mean it's inferior. As to your observations, I may have posted the url https://www.cailliau.org/Alphabetical/L/Lego/Duplo/Train/Rails/Dimensions/ before, or not. And yes, my (my granddaughter's) locomotives can also pull many carriages. The locomotives have changed. It also depends on the wear on the rubber tyres, the state of the batteries etc. Many parameters. Have fun, Robert.
  7. Jim, you wrote: In the thoughts below I used the part numbers as they appear on pages 481 and following of the construction manual. (1) In the construction manual on page 163, on the frame, the rubber liftarms (4198367 rubber liftarm length 2) lie horizontally. They connect to vertical black beams (4142822 beam length 3) that can rotate around fixed blue pins that go through their centre hole. (2) On page 200 the bottom holes of these black vertical beams each get a suspension arm (6055628 steering arm with ball socket) connected to them (the picture on page 200 shows the assembly downside-up, so the bottom holes are at the top in that image). Note that these arms are shown at an angle in all illustrations. Geometrically the sockets for the ball heads are therefore closer together than they would be if the arms were horizontal. They need to be pulled apart slightly if they are to adjust to the Lego grid. (3) On page 218 these arms get the ball heads of the four pegs (4184169 pin with ball head) of the double differential. (4) On page 219 the "shock absorbers" (they are only suspension springs really) are attached and they push the differential away from the frame. That distance puts the steering arms at the angle they were already depicted at, which pulls outwards on the vertical beams. The necessary flexibility can only be achieved by the stretching of the rubber liftarms. If you replace the rubber ones with normal, stiff ones (4211741 for example) then it all feels very different. There is an image at http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/RubberLiftarms.jpeg The distance between the black ball heads indicated by the red line with arrows is a fixed distance (on the differential assembly)
  8. OK. Sorry, I did not know there was more about this specific thing elsewhere. The only reason I wrote anything at all was to point out that the different angles Jim mentioned in his review are indeed desired and not a design mishap in the Arocs. Off for now, R.
  9. Well, I did have a go at Ackerman steering in Lego. Competion: anyone can do it nicer, more robust, more compact? See this page: http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/AckermanSteering/'>http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/AckermanSteering/ There is a link to an .lfx file so those who want to try it may use buiding guide mode in LDD to see how I did it. I'll put some real photos up too, and will make it into a remote-controlled car. (you can also watch http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/ and http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/Steering/ ) to Starmort: it's all a matter of local taxes, people getting money off you just for postage, and other weird things, nothing to do with an open market. That needs a lot more hammering from the European Commission.
  10. To wildboar: coop :-) To 750ACE: thanks, actually I did not know the name! I only remembered the text and diagrams from the Meccano instructions (back in 1955…) Yes, I should have looked for it on Wikipedia & sent the link. I found this: https://en.wikipedia.org/wiki/Ackermann_steering_geometry (quite incomprehensible article in fact) There is a lot more, not to mention suspension methods. To LXF: Hope you found my page & were able to read it. In the intervening hours, I have attempted that steering with Lego, with moderate success. I may publish it. Or not.
  11. Hi LXF: How about this: http://www.cailliau.org/Alphabetical/L/Lego/Models/42043-Arocs/Steering/ (there is nothing else yet about this model though) (And to make some of you jealous: I got my box for 85CHF = 77€ in an after-Christmas sale where I spotted it at 170CHF but was told at the checkout it was 50% off…)
  12. Congratulations on highly professional photos! I was even fooled by some of the outdoor pictures! Just a small thing: you write "Using different links results in different steering angles for both axles." Yes, and you might add that that is desired. In fact when I decided to buy it I was wondering how they would deal with the problem of making all wheels point to the same centre of rotation. Unfortunately the rear wheels do not turn, and at the front wheels in each pair are always kept parallel whereas they should not be. The latter problem is easy to solve in Meccano and almost impossible in Lego. I'd upload a picture, but I'm out of attachment space. For those who are interested: draw a top view of the truck, with rectangles for the wheels. Then draw a line extending one of the two rear axles, say to the left. Choose a point on that line, the point of rotation. From that point, draw lines to the centres of all other wheels. Then rotate the rectangles that represent the wheels so that each is perpendicular to the line that goes through it. Those are the only positions of the wheels that will make the truck steer a circle around the point of rotation without making the tyres slip and therefore wear out. You will notice that the first pair of wheels must turn a little more than the second pair and that at least some of the rear wheels should also turn. I have seen real platforms with four rear axles, all of which turn correctly as well as the double front axle. You will also notice that in each pair the wheel closer to the point of rotation needs to swivel a little more than the wheel on the other side. I know of no Lego set in which steering wheels do that (but there may be some).
  13. Robert Cailliau

    Duplo Trains discussion

    GallardoLU, it is hard for fathers to wait, but you will have to… It's even harder for grandfathers :-)
  14. Robert Cailliau

    Duplo Trains discussion

    Hi GallardoLU, 9 months seems very young indeed! I just looked back into our photo/movie archives: our granddaughter Nora had Duplo when she was 1 year old. At that point she could not put blocks on each other, but thouroughly enjoyed the "dolls", especially the very old type (that were only "heads", see http://alpha.bricklink.com/pages/clone/catalogitem.page?M=dupfig030#T=S&O={"ii":1} ). She played a lot with figures and with separate objects such as cars and the plane until she was 3 or 4. She got her first Duplo train set at her second birthday, and the school (kindergarten) where she went in Paris also had a duplo train set. At 2.5 she discovered her grandmother's normal Lego, which is very neatly kept in a storage box with little trays, all types and colours sorted. She loved that, but only because it was a lot of orderly stuff with lots of the same pieces, not because she constructed much with it. (unfortunately my status here does not allow me to post more pictures). She walked at just under 1 year, and talked (a lot) from somewhat later. She is now 6 and still gets the train out to play with, as well as the farm animals, cars, and things, but for construction she is now into the Lego Friends series and of course did the Ice castle from "Frozen" (41062). The locomotives have a big button on top to make them go, and that was fun when she had enough hand coordination to push that button accurately even when the train was moving. So maybe that is a "turning point": sufficient eye-hand coordination. It's also not easy to put trains onto the rails (see http://www.cailliau.org/Alphabetical/L/Lego/Duplo/Train/Rails/Dimensions/ ) We have 5 locomotives, but two are certainly sufficient, as it all takes a lot of room on the floor. There are some older style railway cars with roofs that open so little figures can be put in, and she also loved to do that, as well as making long trains with lots of figures on them.
  15. Robert Cailliau

    Lego Evolution

    This topic sprang off a discussion on Duplo trains. We were getting off-topic discussing the changes made in time of Duplo trains and the age of the kids the sets were aimed at. A few of us decided it was time to start a new topic, and as I was the one to suggest it in the frist place, here we are. Perhaps this can be incorporated elsewhere, but I could not find a suitable place easily. If it exists, we will be considering moving there. Note: this is NOT about Duplo, though the summary contains mostly references to Duplo. It is about how sets and parts evolved and what the target audiences were/are. Since I also proposed to give a summary of the thoughts expressed and make a back-link, both of these now follow. Enjoy & join. backlink to the original Duplo trains discussion Summary of the off-topic bits of that discussion: (heavily excerpted and some spelling corrections made) Adam Badura, 19 January 2013: How it was with the old “smart locomotive”? As I think it was far more “difficult” and “complex” Peter Nolan, 17 April 2014: The intelli train (http://lego.wikia.com/wiki/10052_Intelligent_Locomotive) was released in 2003. In my experience the extra features do make for more interesting play. However, I'd say that kids would have to be at least three to enjoy the set. Certainly fun for fathers though... Robert Cailliau, 17 April 2014: Yes I agree that the extra features are for older kids. They can probably enjoy the trains until much older (like 67...) IFF there are enough rails and enough switches. :-) Ambroise, 17 April 2014: ...kids were not using all the functionalities, and especially If they want the train to move backwards, they simply take it off, and put it back on the track in the opposite direction. I personally enjoy the Intelli train a lot, they have became quite rare and valuable. Peter Nolan, 19 April 2014: I think that this highlights the problem with the Intelli trains--the system is quite structured and prescriptive. For instance, if the child wants to fill the train up with fuel, they have to place the correct smart brick in the track, start the train and then wait for the train to travel over the smart brick before filling up with fuel (when the train makes the 'glug glug glug' sound). With the current model train, they just need to stop the train and start filling (and the train makes the 'glug glug glug' sound). I think that if the other Intelli functions (e.g. cargo and passenger sounds) had have been designed in a similar fashion it would have worked better as a childs toy. All that being said though, it is a great toy. Robert Cailliau, 19 April 2014: You say play with the intelli-trains is structured and prescriptive, and from what you describe I fully agree, it's too complicated even for 5 year olds. When they are old enough to play with that imaginatively, they have switched away from Duplo. It should not go too much in the other direction though: I learned that the latest issues of the locos no longer stop when they hit something. Now, that is not a "function", it is a protection, and it has been removed. The older issues have a little magnet on the axle that is not driven. It passes before a reed relay at each turn so the computer knows the axle is rotating. When the train falls over, is picked up or gets blocked, the computer stops the motor after a few seconds. That saves batteries and protects against wear and so forth. It also prevents little fingers getting caught in the driving wheels, at least for any length of time. But this feature has been removed. I find that annoying. Peter Nolan, 21 April 2014: On the subject of the latest Duplo trains having fewer features, I think that this is part of general shift in the positioning of Duplo in the market. It seems that Duplo is now being marketed to a younger market than it used to be. I've also noticed that a lot of parents see Duplo as more of a baby/toddler toy rather than something that is good for kids up to 5 years or so. It seems to be that people decide that once their child is a certain age it is time to get rid of the Duplo and then move on to Lego. (sorry if I'm repeating some of the sentiments that have been expressed earlier in this thread). At the moment I find that my son is happy playing with both Duplo and Lego and creating hybrid models (not everyone realises that Duplo and Lego are compatible it seems). When you throw in some Duplo Toolo (bought second-hand, like the Intelli trains) there are all sorts of play possibilities. Robert Cailliau, 21 April 2014: Yup, agreed. Now that you raise the point, there is also a degree of age-variety in Duplo: the big blocks are no longer very attractive after 5 or 6, but the trains certainly could go for much longer. Again, IFF there are enough rails. I consistently find that train sets of any make or scale have far too few straight rails. An oval, even with an intellitrain soon loses all attraction. And yes, few people realise that Duplo is called Duplo because it is "double size" and compatible (to some extent) with the single-size blocks. Thanks for reminding us of it. Toolo is very rare. Strange stuff, well designed. I ony have some incomplete things that Nora has "inherited" from cousins, but she does not play with it. zg0, 21 April 2014: my first try to make duplo compatible train base from lego pieces. Adam Badura, 21 April 2014: Nice! Be sure to check it with switches, crossings (both rail-rail and rail-street), and bridge. Those are places where other Duplo bases fail. For example 10558: Number Train doesn't fit on that type of track and that is sad. Yours looks like it would have no issue but it is always good to keep that in mind. zephyr1934, 22 April 2014: The intellitrain was from an era where Lego figured the under 3 set would be playing with quatro or primo. The rest of the toy industry is pushing "realism" down to an insanely young age these days. I played with Tonka trucks (the real ones, made of metal) until I was at least 10, but now the toy industry has the blue isle all figured out. First dinosaurs, then trains, the superheros, then .... With trucks falling by the wayside somewhere around 5 years of age. I think duplo has also been pushed to younger ages as a result of consumer demand. It is too bad, because the modern lego sets can't be anything more than a model for the 5-8 yr olds (as in, there is very little room to go off and build what you like with so many specialized pieces, you can build the main model and that is it). For the simplicity of the bricks my first grader still plays with duplo even though he has a room full of system bricks. Nolan ... the trains certainly could go for much longer. Again, IFF there are enough rails. As it happens, my son's train set does seem to have many more curved rails than straight. We are yet to run out of either though... BTW do you mean IFF in the mathematical sense? Robert Cailliau, on 21 April 2014 - 04:07 PM, said: Toolo is very rare. Strange stuff, well designed. Peter Nolan, 22 April 2014: Toolo is quite interesting. Some of the parts look like they would be very expensive to produce--the standard 2x4 block has screw threads on five surfaces, which would necessitate quite complex mould tooling. Although there are no retail Toolo sets available now, you can still buy two educational sets: http://education.lego.com/en-us/lego-education-product-database/preschool/45002-tech-machines http://education.lego.com/en-us/lego-education-product-database/machines-and-mechanisms/9656-early-simple-machines-set zg0, 22 April 2014: disagree. lego bricks sets long time was 3+, now 4+. creator was 4+, now 6+/7+. so lego clears 1-2 years from lego for duplo. and in 2013-2014 set we can see that duplo sets became more "constructional". cars from monolitic became consists from 4-5 pieces. and pieces became more universal. Peter Nolan, 22 April 2014: Interesting. I was skeptical to start with, so had a look at some of the new Duplo sets and can see your point. If you compare the new ambulance (10527) with the old one (4979) the new one does indeed have more parts.
  16. Robert Cailliau

    Duplo Trains discussion

    It will fit: there is enough play. Most of Lego's own examples of layouts do not fit exactly and need the play. As soon as there is a piec of track at an angle the trancendental lengths of cos(L) and/or sin(L) give those problems (L being the length of a straight track). See pages linked to from http://www.cailliau.org/Alphabetical/L/Lego/Duplo/ As to the custom-built locomotives with different wheels not going up bridges, that is because the Duplo locomotives have wheels that act as pinions on the racks at the sied of the bridge slopes (see same pages). A good custom-built locomotive would probably have to use those wheels. Can be done with "destructive" techniques, meaning taking a real Duplo loco to pieces to use its parts in another construction.
  17. Robert Cailliau

    Duplo Trains discussion

    Apparently. Though I think most of our recent discussions should be under mathematics. :-)
  18. Robert Cailliau

    Duplo Trains discussion

    Guy: I looked at your javascript ("inspect source" etc) and saw it is table driven. Should not be too difficult to attempt to translate into LiveCode (if ever I get enough time again). Mechanical computation is very interesting indeed. About two years ago I was at a special presentation at the Geneva Science Museum where they showed two of the four surviving machines made by Pascal. As usual, the carry-over mechanism was the most fragile and difficult. The Science Museum in London built part of Babbage's Analytical engine; perhaps with today's crowd funding a bigger part could be built. I'm the proud owner of a Curta calculator which I bought in 1968 to help with my engineering studies. I can still extract square roots with it. Today's youngsters can't believe what they see when I take the cover off: http://www.cailliau..../zCurta-en.html Ah, and Märklin had a cross-switch which had linked points, though I have not given any thought as to whether it would be useful in your designs. Anyway it would be a sprung set. If you type "marklin double cross switch" you will find images. Perhaps this discussion should be taken to an entirely different forum, not even Lego…
  19. Robert Cailliau

    Duplo Trains discussion

    Guy: This is all rather unbelievable… IFF I go see the Grenoble guys and their machine, I'll tell you. Your interactive tracks are fantastic. I'd like to go into how you do the interactive displays, but unfortunately I'really in dire time-need right now. Best!
  20. Robert Cailliau

    Duplo Trains discussion

    As far as I can remember from my courses on finite state automata, a universal Turing machine needs only 7 flip-flops. Of course, being a universal machine, it needs to read the program defining the machine it emulates, needs to keep a record of the state of that machine, and then also needs to read the input and write the output. All of this potentially needs and infinite "tape" and an enormous amount of shifting tape back and forth. So yes, there is an "infinite" thing needed if it is only done with switches. Maybe it could be done with pushing cars around, acting as "bits" on tape, whereby the tape would be some length of straight track, sufficiently long for a given machine to emulate and a given input (potentially infinite). Each car could represent a single "bit', and have a "sense" so that it can be made to represent each of the two bit states (usually called 0 and 1, but I don't like that as it smacks of numbers). Well, something for another lifetime. :-)
  21. Robert Cailliau

    Duplo Trains discussion

    :-) There was/is a real Lego Turing machine: http://www.turing2012.fr/?p=530〈=en Note that there were a few others built around the same time (Turing 100th anniversary), like this one : http://www.legoturingmachine.org which however is NOT a Lego machine: the Turing code is inside the NXT brick, so that is cheating. The one from the people in Grenoble is the only one I know of that is entirely made of Lego components with no hidden tricks. As I live close to Grenoble, I'll go and have a look sometime.
  22. Robert Cailliau

    Duplo Trains discussion

    Peter: I may have mentioned this in an earlier post, but your son's friend's brother, the aspiring coder, might want to have a look at LiveCode, get the free system, and instantly do some interesting stuff. I have a beginner's page here: http://www.cailliau.org/Alphabetical/L/LiveCode/Annotated%20Examples/ He will probably be most interested in the fact that he can make his own apps for his smartphone (which 11 year old does not have a smartphone these days?)
  23. Robert Cailliau

    Duplo Trains discussion

    Owwww.... I need another life to explore all this. Next stop: a universal Turing machine? Maybe Douglas Adams had sensed something, except that in reality the computer the mice were building used Duplo switches. Fortunately we know the answer without having to wait for the locos to reach the end: 42. Guy, I wished I had your stamina in all this. My granddaughter has now switched to regular Lego.
  24. Robert Cailliau

    Duplo Trains discussion

    This is great! Fortunately Guy puts it all on his cr31 site. I wonder if the Duplo kids who inspired it all will be interested when they have gorwn up. :-)