Why elevator problems are good

Discussion in 'General Electronics Chat' started by KL7AJ, May 5, 2009.

  1. KL7AJ

    Thread Starter AAC Fanatic!

    Nov 4, 2008
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    Way back when I was taking engineering in college (won't tell you how long ago that was) we were griping about these unsolvable elevator problems.

    Is there a conspiracy afoot to make life miserable for engineering students?

    Of course there is. But it's a good conspiracy.

    What makes elevator problems special is that they have no PERFECT solution, but they have many WORKABLE solutions. This is a fact of life you need to know before you get into the engineering world. Very seldom will you have a blank slate to work on an engineering problem.
    If you're one of the very lucky few, you might get to work at JPL designing MARS rovers, which is pretty much carte blanche to do things perfectly. (The Rovers are those exceedingly rare instances of something that worked BETTER than they were designed to. They were meant to last three months. The Golden Gate Bridge is another one of those rarities)

    However, MOST engineering involves "making a silk purse out of a sow's ear." Elevator problems are fabulous practice for this. They force you to think about how best to do something with the resources you've got.

    Now you know. :)

    Eric
     
  2. Jack Bourne

    Active Member

    Apr 30, 2008
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    What exactly is the elevator problem?
     
  3. KL7AJ

    Thread Starter AAC Fanatic!

    Nov 4, 2008
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  4. PRS

    Well-Known Member

    Aug 24, 2008
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    Say you have three floors serviced by a single elevator. Right now the elevator is between the 1st and 2nd floors and moving upward, destined for the 3rd floor. At this moment someone presses the up button on the second floor. Should the elevator stop? What if he pressed the down button? The elevator needs a logical way to go about its business.

    I intend to make a scale model with pushbuttons someday. Also a traffic light. They'll make great conversation pieces for my living room.
     
  5. Jack Bourne

    Active Member

    Apr 30, 2008
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    The elevator will have defined rules, say it needs to be gien 3/4 floor warning to stop so then it would not stop in your scenario.
    I am using common sense but in this case, like the problem said, it may not be the best solution.
    It is made sooo much more difficult by the fact that you should make a general rule.

    Harder still would be to design the program for the lift in Charlie and the Chocolate Factory.
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    It all depends of the rules that you establish.

    Just go to big buildings and you will find uncountable ways of trying to economize time / resources / wear or please the users... you name it.

    Besides some theoretical and sometimes obscure / esoteric ways, I understand it is quite hard to demonstrate that a certain set of rules gives the best use. Unless you start a record to produce statistics.

    I always dreamed to build at a hobby level, a set of several small elevators with different sets of rules aimed to optimize something. I find the idea of programming the whole thing very appealing but cost and time are discouraging.

    I never passed through that kind of experience but I agree that in the long term it has benefits.

    I find this subject fascinating.
     
  7. davebee

    Well-Known Member

    Oct 22, 2008
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    My nephew learned a cool elevator trick - when he was alone, and in a hurry to get to his floor, first he'd toggle the emergency stop, then hit his floor button. The emergency stop would apparently clear every current stop request from the queue, so he'd get to go directly to his floor.

    He got so accustomed to doing this when he was alone that one day when he got into the elevator when it was full of people, he instinctively pulled his little trick before realizing that he'd just cancelled everyone's floor requests. As they all glared at him, all he could do was to stare at the wall with a red face until he was able to get off!
     
  8. Jack Bourne

    Active Member

    Apr 30, 2008
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    Very funny, I always think it will call someone.
     
  9. PRS

    Well-Known Member

    Aug 24, 2008
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    I've thought of various ways to make my model elevator. I actually made one using a long wooden box shaped like a trough. A threaded screw ran down the middle. As it turned, due to a motor, it moved a small box (representing the elevator) from one end of the box to the other. Problem was, not having a metal lathe, I made wooden gears for the motor transmission and it was just too darn loud! :(
     
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