PLEASE HELP, TRYING TO DO SENIOR PROJECT DUE TOMORROW

Discussion in 'Homework Help' started by Yarely, Mar 11, 2015.

  1. Yarely

    Thread Starter New Member

    Mar 11, 2015
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    So I have this circuit built (shown in the attachments) what it does is that you plug the battery in, turn the switch on, put it in a dark room, and once light hits the photo cell the buzzer starts going off. However, I want to modify the circuit so that I can put a weight sensor on it so that it will go off when someone steps on the two aluminum rectangles. I haven't finished making the weight thing yet but I was putting it off because I didn't even know if it was possible to put a weight sensor switch on this circuit, and if so, can someone explain to me how it is possible, thank you! :)
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    A picture of an assembled circuit, especially one in which all of the traces are on the other side of the board, doesn't give us much to go on.

    Do you know HOW the existing circuit works? Or is it just a circuit that you built from a kit or from a schematic?

    What are the conditions, from an electrical standpoint, that result in the buzzer sounding and not sounding?

    What is the physical mechanism by which you were planning to detect someone stepping onto the aluminum rectangles?

    Is this only a small part of your Senior Project, or is this the major portion?
     
  3. Yarely

    Thread Starter New Member

    Mar 11, 2015
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    I built it from a kit, and it's a small portion its due tomorrow, but the presentation isn't due until May so I was thinking of something else, but what I need help on is due tomorrow
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    Okay, so if you are going to modify a circuit, you need to have an fair understanding of the circuit being modified -- at least the part you are interfacing to.

    Do you know how that kit works? What happens when light hits the photocell and how that then results in buzzer going off?

    If you replace the photocell with a custom sensor circuit X, what behavior does X have to exhibit in order to make the buzzer circuit work as desired?

    How are you planning to turn these two aluminum plates into a weight sensor?
     
  5. Yarely

    Thread Starter New Member

    Mar 11, 2015
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    I don't know all the aspects, but from what I can tell, the photocell makes the buzzer go off, because it's a light sensitive switch? and I plan on separating the two aluminum plates with wood after I sand paper it down so that when someone steps on it, the plate goes down, and touches the other plate thus closing the circuit, but it's aluminum flashing so its flexible enough to be stepped on so that the two plates can touch, then when the person steps off, they stop touching
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    Have you looked at the data sheet for the photocell to see how it works and what its characteristics are?
     
  7. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Can you post a schematic?
     
  8. WBahn

    Moderator

    Mar 31, 2012
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    This is a Senior Project for what degree? What level? What major? That will help us give more appropriately targeted advise.
     
  9. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Just put the weight switch across the light sensor terminals.
     
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