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auto switch off water dispensers

Discussion in 'General Electronics Discussion' started by andrewsymonds, Nov 15, 2012.

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  1. andrewsymonds

    andrewsymonds

    4
    0
    Nov 15, 2012
    hello everyone,

    I am planning to make a water dispenser. This is supported by an automatic switch off mechanism. Switching it on is not a problem but i don't know how to switch it off. I am a beginner in electronics and don't have much idea. However i don't want to use devices that float in the cup/bottle by which i can turn it off. I want some other sensors by which i can detect the water level of cups/bottles of different sizes and turn it off. So cannot attach any thing to the bottle also. i plan do it for only one type of liquid and i will highly encourage if someone can help me do it for different liquids also. I am making this so that it can help me in daily life also. I wish to design it by myself. Can somebody help me how do i continue to work on my project.

    Note: i had planned to use photoelectric sensors. I thought of throwing a beam of light via a laser on the liquid and then catch the beam of light via the sensors and by this i can detect the level of water. But the problem is that the result is inconsistent for different sizes of bottles (also for different liquids).

    Doubt: i am thinking of using position sensors at the corners (of the place below the tap to that at the extreme bottom) by which i can calculate the exact position of the liquid and by using several of them i can calculate the approximate volume and then pour the liquid of that quantity.

    Here is a rough sketch of the plan that i have made using position sensors:(there as an attachment-note: i will use anyone between the tap an button).

    Please help me with my project as soon as possible.
    Looking forward for your valuable remarks.:)
     

    Attached Files:

  2. wingnut

    wingnut

    242
    9
    Aug 9, 2012
    Place your container on an electronic scale or switch that when it is full it weighs enough to press on the switch with enough force (a bell switch) to switch it off.

    Good luck
     
  3. andrewsymonds

    andrewsymonds

    4
    0
    Nov 15, 2012
    hey this is for the the reply given by wingnut,

    I wanted to say that the weight for different containers are different and as i had stated before i wanted to make my project valid for containers of different sizes. Obviously the weight for a container made of plastic will be less than the weight of a thermos. so how can we apply the method stated by you.
    Also it cannot be valid if the liquid is different as the weight/mass of 20L of coke is different than that of 20L of water. Even though that is not my primary focus i have just given this example to illustrate my point.

    If it can work via mass/weight of the container please explain your procedure more precisely because in that case i have misunderstood you. My sincere apologies for this case.
     
  4. wingnut

    wingnut

    242
    9
    Aug 9, 2012
    Say you take a Coke bottle full of water and invert it into a glass. Water will flow out of the bottle till the water in the glass rises to reach the mouth of the bottle. You dont need anything to regulate the level of the liquid, (used in automatic pet waterers and water coolers).

    The simplest electronic way to detect water height is to have two upside down probes, which, as the water rises, will close a circuit. Water conducts electricity - even distilled water does slightly.

    Using your laser suggestion, or any light beam shone at an angle into a liquid will diffract (bend) the beam more than air would. If you had light sensors and a base (reference) light intensity, then as the water reached the level of the sensor, it would diffract light away from the sensor. With a microprocessor you could get a reference light intensity and at a certain height (with a liquid refracting) you would get a different light intensity (presuming a transparent container).

    Another thought is to shine light at an angle from above. Light reflects off the surface of a liquid. A light sensor at the correct angle could determine liquid level. I tried this with a flashlight, slowly raising a bowl of water and watching the reflection against my refrigerator. It worked surprisingly well.
     
    Last edited: Nov 15, 2012
  5. andrewsymonds

    andrewsymonds

    4
    0
    Nov 15, 2012
    hmm all right

    i think your method is extremely reasonable. Thanks a lot.
    I will give it a try for sure.
    I will post whatever my result is as soon as possible (probably one one or two weeks later).

    However i will be in touch with all other people so that i can find many methods to solve this problem. This will surely help me in the future.

    Thanks
     
  6. wingnut

    wingnut

    242
    9
    Aug 9, 2012
    Thanks for the feedback. Keep in touch.
     
  7. andrewsymonds

    andrewsymonds

    4
    0
    Nov 15, 2012
    oh this is for wingnut again,

    I actually didnt know what actually a probe is. After i read your reply i searched it on the internet and found that what u said was actually a great method.

    However i have no idea how to program the probe. I dont know which software should i use.
    Can i use Arduino?
    This is because i just know the programming for this software.
    Please let me know if i need to use other softwares
     
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