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Hello ! Some of us are looking for new Lego-challenges. So, I created this one, which is called : "the Labyrinthus challenge". "The goal is to build a robot which could enter into a labyrinth (made of black tape on white floor or so) and find it's (...) (25 years ago, 12-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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Got it figured out. Using the principles of right handed recursion, you can have the robot follow the right wall and it will eventually get to the light and also get out of the maze again. Incidentally, right handed recursion will get you out of any (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) Mike> Got it figured out. Using the principles of right handed Mike> recursion, you can have the robot follow the right wall and Mike> it will eventually get to the light and also get out of the Mike> maze again. Mike> Incidentally, right (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) Yes, unfortunately the current firmware implementation from LEGO doesn't have a call stack, so you can not build recursive routines. :-( On the other hand I can imagine labyrinths where that bot would never be able to do anything out of them. (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) True. From what I know the right hand (and left hand) rucursion always works in flat labyrinths (no bridges, stairs, tunnels etc). However, I like Philippe's challenge and think it would be nice to look at a small robot finding its way inside (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) Actually you don't need a recursive algorithm to apply the right hand rule. Simply follow either the right (or left) wall and you'll arrive at the exit. For a maze with no exit but a "special point" to reach inside (like Philippe's one), the (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | RE: New Lego challenge !
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(...) Hmm, maybe it is finally time to try a real application with pbFORTH. With it's large memory space, you can map out the maze and represent it as a bitmap, or tree of paths. You CAN do recursion in pbFORTH, but it's ugly. I rememeber a thread a (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | RE: New Lego challenge !
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(...) This may be a good idea, and in fact it may be a good jump start to many people out there that never tried pbFORTH because the inertia of learning a new language (like me!!). If you can provide a nice implementation of this and explain it to (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) A call stack is not an absolute requirement to do recursive processing, it just makes it easier. I have written recursive processes with only an array. -Wes (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) To be more specific, the "right hand rule" is not a recursive algorithm at all in the classic sense. We like to think of it that way because the "traveler" will traverse parts of the maze repeatedly, in the worst case the whole maze. However, (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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Hi, This sounds like a great challenge! One quick question, is the square containing the light beacon marked in any way? Perhaps a different color floor for that square. It would make goal determination much easier. Or is part of the challenge (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) The right (or left (-: ) -hand rule seems to be simple but not the most efficient. That's why I included the light beacon. Providing you have the right beacon detector (let's build one!), and you don't know which direction is the best, you can (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) light (...) in (...) able to do anything out of them. (...) Unfortunately, the default RCX firmware doesn't support arrays, either. Also, the assertion that you can simply follow a wall in order to traverse an entire labyrinth actually depends (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | RE: New Lego challenge !
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This is a REALLY good idea. Here's something I had kicking around in my head... 1. Making a maze that we can all use is kinda hard. 2. Making a bot small enough to fit a standard buildable maze is really hard. I propose we invert the problem a (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | RE: New Lego challenge !
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At 12:52 PM 9/13/99 +0000, you wrote: <snip> (...) The argument quickly turned into one of our definition wars about what exactly is recursion. Joel Shafer joel@connect.net (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | RE: New Lego challenge !
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<snipped discussion about recursive vs non-recursive> (...) Joel, could you please define definition war more exactly? And maybe give an example of why it's not recursive... Cheers, Ralph Hempel - P.Eng ---...--- Check out pbFORTH for LEGO (...) (25 years ago, 13-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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Ralph Hempel wrote in message <000001befe2a$c62ef4...pro150>... (...) <snip> Excellent Idea! That way, the light sensor could 'hover' over the maze, and be moved in an X and Y direction to 'traverse' it. I may attempt this, as I have very limited (...) (25 years ago, 14-Sep-99, to lugnet.robotics)
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| | Re: definition war definition war (was: New Lego challenge !)
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(...) Rudimentary*) BNG form: definition war ::= [definition war] war definition ::= {I say so} war ::= {You're wrong} Braces denote atoms. Non-recursive as it never calls itself. It just sends telegrams. Cheers, Martin "sorry for bargin' in" E. (...) (25 years ago, 15-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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Richard wrote : (...) Depending on the number of sensors used, there will be no more sensors inputs to add a "beacon detector". My first idea was to use some kind of rotating sensor to detect where the beacon is, and to decide when we are near (...) (25 years ago, 15-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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Ralph Hempel wrote : (...) This is a great idea, and this could be usefull for at least two reasons: -If you don't have room to create a real maze -We don't have an easy way to make a real bot move in either precise x or y direction (because of (...) (25 years ago, 15-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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(...) Actually, a synchro-bot is pretty good at this. In case you missed previous threads, this 'bot is one that the direction of all of its wheels are synchronized. The robot can drive in any direction but its orientation never changes. With a (...) (25 years ago, 15-Sep-99, to lugnet.robotics)
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| | Re: New Lego challenge !
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On Wed, 15 Sep 1999, Paul Speed wrote: <snip> (...) <snip> (...) Depending on how you define "stock Mindstorms parts", you _can_ make a synchro-bot. You can use a differential instead of the turntable, hence you need one RIS for each wheel! This (...) (25 years ago, 16-Sep-99, to lugnet.robotics)
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