mini water pump circuit?

Discussion in 'The Projects Forum' started by jsca, Apr 30, 2007.

  1. jsca

    Thread Starter New Member

    Apr 30, 2007
    i'm currently working on a project that involves designing a mechanism that would allow water to be sucked out of a tank and pumped back into it. so this is kinda how it works:

    - there's a small container of water (about 50ml)
    - there's a motion sensor connected to it
    - when it detects a movement, water is automatically drawn out of the container
    - after 2 minutes, water (the same water that was drawn out) is automatically pumped back into the container

    i was told by a friend that a motor might be needed to operate the pump? i'm just unsure of how i'm going to make this mechanism/circuit...i have no experience in designing whatever help will be very much appreciated! thanks!
  2. recca02

    Senior Member

    Apr 2, 2007
    what sort of motion is detected,
    i mean is it some disturbance in the water or something else,
    why is the motion caused, based on this a sensor/transducer will be required,
    also is the disturbance large or small?
    u might require a motor to pump the wter out or in but if apt designing is done for water flow u wont need a pump for both.
    of course all pumps req motor unless u are going to use fluid flow to turn the rotors as in case of turbines.
    a valve can be actuated after 2 min of whole water evacuation.
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    You'll need a means of controlling the pump motor, such as relay, MOSFET, SCR, or triac. You might need some solenoid valves, depending on your exact setup. You'll need a circuit to monitor your sensor and provide current to the relay (or whatever) - this can be as simple as a transistor switch, depending on the specifics of your sensor. You'll need a timer for your two minute interval.

    I suggest you start by looking at the needs of your pump motor and your motion sensor. Do you have any information on either one?
  4. jsca

    Thread Starter New Member

    Apr 30, 2007
    well what i'm trying to design is this: a mini fish bowl attached onto a bathroom faucet. when the tap is turned on, water from the fish bowl is drained (into a container). after 2mins, water is pumped back into the fish bowl.

    i'm designing this for kids to be used in a childcare centre
    this whole system with the fishbowl (which has a toy fish in it) is meant to teach kids not to waste water and only use whatever's needed.

    recca02, thingmaker3: i was just wondering whether there's a simple, straightforward way to make this work? from what you both have suggested, it seems like this won't be an easy system to make...:(

    (and no, sorry, i don't have any tech specs on any parts)
  5. recca02

    Senior Member

    Apr 2, 2007
    well this will very much depend on your knowledge of electronics and whether u
    have worked on something similar before.
    best wud be to take some help from an experienced person on this.
    from what i understand abt the project.
    u may require a water level indicator so that a minute change in the water level can be sensed when water comes from the tap.
    this level will need to be compared using opamp as comparator to some set point and a relay contact can be made to operate the pump motor to pump out the might also require a bistable multivibrator .
    another pump might be required if you dont want the piping system to get complex with valves. this pump will also use a relay switch whose contact
    wud be triggered by a timer ckt which will be again triggered by the same comparator to run after certain time that u wud desire (the comparator's
    set point wud have to be different if the motor is to operate after complete drainage.
    all this may seem complicated but is very easy for a person who knows abt electronics. he might also be able to come up witha much better idea.
    all in all it wud only be hard if u attempt this on your own try to bother someone else too.

    i really appreciate the work u are doing.
    wish u luck.
  6. jsca

    Thread Starter New Member

    Apr 30, 2007
    yea i was originally planning to do this on my own...but now that you've laid out the details it seems like i'll most likely be needing some help from someone else with my project!

    thanks heaps for your help! it was very much appreciated :)
  7. kender

    AAC Fanatic!

    Jan 17, 2007
    For such a small quantity of water I would use a peristaltic pump.
    The motion sensor depends on the environment and scenario. Look into passive IR (PIR) or beam-interruption sensors.