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Engineering project 2013

24

Comments

  • #32
    kirving
    Registered Users Posts: 5,874 ✭✭✭kirving


    Don't go with a hoover attachemnt. It might work, but you've used something else to solve a problem. While this is generally a great idea in engineering(keep it simple), the task here is to solve a problem yourself, showing off as much engineering innovation and workmanship as you can.

    I'd be using a bellows, connected to a piston powered by a solenoid. The air line would be flexible and the piston would not move. It would have to be very refined to work, but it's doable.


  • #33
    chloe04
    Registered Users Posts: 9 ✭chloe04


    i didnt even do metalwork for the junior cert, flying with the higher theory but havent a clue what to do about the project at all, help :(


  • #34
    Wils110
    Closed Accounts Posts: 548 ✭✭✭Wils110


    Mini USB Hoover thing for office desks


  • #35
    chloe04
    Registered Users Posts: 9 ✭chloe04


    Wils110 wrote: »
    Mini USB Hoover thing for office desks

    doubt thatd work, suction is too weak


  • #36
    Wils110
    Closed Accounts Posts: 548 ✭✭✭Wils110


    Engineering....ramp it up wouldn't need much suction it's only a table tennis ball


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  • #37
    partyatmygaff
    Registered Users Posts: 10,992 ✭✭✭✭partyatmygaff


    Potentially a very difficult project compared to past years. Depending on how you hack it, it may need a lot of fine-tuned and precise motor control.

    Suction is an option but it's fraught with complications and very difficult to achieve enough suction with just 9V. Not only that but you still have to design a mechanism capable of moving around in at least two axes.

    Personally, i'd start looking in to two solutions:
    A)
    Get four high torque servo motors and make a three-fingered "grabber" than can move in three axes and close/open with four potentiometers/555 timer servo controller circuits.

    One geared to a chain/belt to control the X axis, another to control the Y axis and another with a rack and pinion (Or something similar) control movement along the Z axis. Then devise some kind of mechanism to open and close the three-fingered grabber and control that with the fourth servo.

    It's not a very elegant way of doing things and you'll need to center your design around the mechanism to prevent problems down the line but it's definitely functional.

    B)
    Do something similar but with stepper motors and a PIC/AVR microcontroller and a tennis-ball sized scoop rather than a fingered grabber. Link the X, Y values of a joystick (Like this) to the stepper motors controlling the X and Y axes of your mechanism. Once you've got that sorted, get a switch and program that switch to drop the scoop by a variable distance. What I mean by that is if you need your scoop to drop by 50mm to successfully pick up a ball, program the microcontroller to lower the scoop by 10-20-15-30-25-40-50cm depending on your number of attempts and then release it over the hatch. Essentially what you're doing is making it successfully pick up the ball 1/7 times.

    It's very elegant and quite a bit easier to work with from a mechanical point of view but definitely not for everybody. Without any experience, you'll have to learn it as you go along using internet tutorials and the like. Doable but unless you're already familiar with some of the fundamentals you'd be better off sticking with discrete components and at most simple ICs like the 555.


  • #38
    Supermensch
    Registered Users Posts: 270 ✭✭Supermensch


    Just to clarify, all the electrical constraints entail is that the potential difference at any two points in the circuit does not exceed 9 volts. The brief is rather misleading with its' "Electric power does not exceed 9 volts", mainly because voltage is not a measure of electric power :rolleyes: , but also because when people see the 9 volts they think one nine volt battery. 9 volts is only the largest potential difference you are allowed to have in your circuit, so it is permissible to have a number of 9V batteries in your design, or indeed to connect a number of 9V batteries together in parallel.

    Can anyone find alternative existing claw crane designs? All I can find is the standard square container with the claw sitting on rails design for my research for the Investigation of Solutions bit.


  • #39
    chosen1
    Registered Users Posts: 411 ✭✭chosen1


    padraig100 wrote: »
    a hoover that runs off 9 volts?? good luck son..
    It's not that difficult to achieve that suction on 9v. I have a working model done up already that lifts the ball.


  • #40
    TheHardyViper
    Registered Users Posts: 18 ✭TheHardyViper


    Just a reminder, the brief says there has to be skill involved, so if your project involves suction you'll need some kind of objective other than turning on and off a pump


  • #41
    chloe04
    Registered Users Posts: 9 ✭chloe04


    i really think suction would be the hardest option, im choosing grab for mine, the over and back will be grand with 2 different switches, but anyone have any idea how ill make it move down and grab the ball?


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  • #42
    TheHardyViper
    Registered Users Posts: 18 ✭TheHardyViper


    I think a motor with a pulley is the simplest option for how to make it move down. As for grabbing, that's pretty difficult. Something designed to simply 'pick up' the ball might be easier


  • #43
    iFreeley
    Registered Users Posts: 73 ✭✭iFreeley


    How long is everyone elses claws? Afraid i wont have much room for moving up and down?


  • #44
    DMC1230009
    Registered Users Posts: 3 ✭DMC1230009


    anyone know where to get a 9 volt vacuum pump?


  • #45
    Supermensch
    Registered Users Posts: 270 ✭✭Supermensch


    DMC1230009 wrote: »
    anyone know where to get a 9 volt vacuum pump?

    Have a look at USB Vacuums. The USB standard is 5 Volts, and 500mA (I think).

    Quick search on Amazon;
    http://www.amazon.com/CablesToBuy-Black-Powered-Vacuum-Cleaner/dp/B000VXOPLQ/ref=sr_1_1?ie=UTF8&qid=1352505768&sr=8-1&keywords=usb+vacuum
    iFreeley wrote: »
    How long is everyone elses claws? Afraid i wont have much room for moving up and down?

    Height of a ping pong ball is about 50mm. Full raised, the claw in my design is only 100mm above the area where the ball sits.


  • #46
    DMC1230009
    Registered Users Posts: 3 ✭DMC1230009


    thanks but i dont think it would be powerful enough.


  • #47
    chloe04
    Registered Users Posts: 9 ✭chloe04


    i chose to use something to scoop up the ball instead, the lowering and scooping up will be fine but does anyone have any ideas how to drop the ball?


  • #48
    EoinLoook
    Registered Users Posts: 2 ✭EoinLoook


    I'm using a suction mechanism that actually seems to be the simplest option regarding circuitry. I've tried a simple fan and motor job in a plastic bottle or tube works perfectly. It works off 9v of power too.


  • #49
    DMC1230009
    Registered Users Posts: 3 ✭DMC1230009


    That would be good but how could you harnass it to use in the project?


  • #50
    BrendonB
    Registered Users Posts: 2 ✭BrendonB


    So what is everyones take on the scoring system?


  • #51
    BrendonB
    Registered Users Posts: 2 ✭BrendonB


    chloe04 wrote: »
    i chose to use something to scoop up the ball instead, the lowering and scooping up will be fine but does anyone have any ideas how to drop the ball?

    How are you lowering and scooping the ball? If you are using a motor,im sure you can reverse motion and drop the ball? just a suggestion. :)


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  • #52
    sailordog13
    Registered Users Posts: 90 ✭✭sailordog13


    From reading the brief, I don't believe it would breach the guidelines by using an external transformer to supply your 9V, freeing up valuable space.

    SD13


  • #53
    EoinLoook
    Registered Users Posts: 2 ✭EoinLoook


    DMC1230009 wrote: »
    That would be good but how could you harnass it to use in the project?


    I'm thinking of putting the fan in a tube and then connecting that by string to a motor and spool that can lower it up and down. That motor would be on a trolley that will move on one axis across one side of the project.


  • #54
    iFreeley
    Registered Users Posts: 73 ✭✭iFreeley


    How's everyone else gettin on with the project?


  • #55
    chloe04
    Registered Users Posts: 9 ✭chloe04


    still havent started, totally clueless


  • #56
    jamo2oo9
    Registered Users Posts: 5,780 ✭✭✭jamo2oo9


    Have the parts nearly finished and ready for assembly. Aiming to get the structure finished by Christmas and then start the electronics and tidying it up in the New Year.

    It's not a difficult project if you do the research and investigation. Want the A's? Get working lad!


  • #57
    iFreeley
    Registered Users Posts: 73 ✭✭iFreeley


    You gonna use a joystick for the x and y axis? or just use 2 seperate 2 way switches?


  • #58
    CWF
    Registered Users Posts: 1,052 ✭✭✭CWF


    jamo2oo9 wrote: »
    Have the parts nearly finished and ready for assembly. Aiming to get the structure finished by Christmas and then start the electronics and tidying it up in the New Year.

    It's not a difficult project if you do the research and investigation. Want the A's? Get working lad!

    Hate you.


  • #59
    Daniel L
    Registered Users Posts: 73 ✭✭Daniel L


    Does any1 have any good ideas on a grab mechanism? i have the manouvers of the crane pretty much down its just grabbing that table tennis ball is the hardest part.


  • #60
    jamo2oo9
    Registered Users Posts: 5,780 ✭✭✭jamo2oo9


    CWF wrote: »
    Hate you.
    Hard work pays it off!
    Daniel L wrote: »
    Does any1 have any good ideas on a grab mechanism? i have the manouvers of the crane pretty much down its just grabbing that table tennis ball is the hardest part.

    Have a look at the grab mechanisms used by cranes in scrapyards. That will help you a lot. My Engineering teacher said that the more you study how it opens and closes its jaws, the better the idea you will have for your design.

    Mine's done from mind, really simple. Requires no motors to grab or release the table tennis ball. Does require a little bit of complex drawings on the plastic sheeting. Just think outside the box. :)


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  • #61
    Daniel L
    Registered Users Posts: 73 ✭✭Daniel L


    yeh i have done that :) its the timing that really puts us under pressure because id like to work on a design that i know how to make instead of 1 the teacher gives us and your there goin how do we do this :s thanks anyway, :)


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