555 water level alarm

Discussion in 'General Electronics Chat' started by @android, Jan 4, 2012.

  1. @android

    Thread Starter Member

    Dec 15, 2011
    178
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    Guys will this work?
     
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  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Not very loud, and not for very long, as the wires will become anode and cathode, increasing their resistance.

    If the ater is pure or deionized, it won't work at all.

    What 'grade' of water are you trying to get the level of?

    Sometimes an ultrasonic rangefinder works best, when looking down.

    Other times, "normal" water will close contacts similar to the one above to turn on an alarm or bilge pump.

    Click "Search" in the userbar at top and type in "water level" to find many solutions that have been in use and work well.
     
  3. Maged A. Mohamed

    Member

    Apr 6, 2011
    18
    1
    The problem with this cct is the load current must flow through the probes and water, so the resistance must be very low
    it is better to put the probes between the reset pin 4 and GND and use the 7555 CMOS version
    Another idea to connect the probes between threshold pin 5 and VCC so the sound (frequency) will vary as water builds up
     
  4. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    I'm not gonna use this for pure water. This is for normal tap water. Will 6V suffice current requirements? Because water will offer much resistance. Right?
     
  5. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    you can try this simple circuit........

    [​IMG]
     
    Last edited: Jan 4, 2012
  6. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    What about my question?
     
  7. KASSIMSAMJI

    New Member

    Dec 30, 2011
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    0
    Sound nice
     
  8. Maged A. Mohamed

    Member

    Apr 6, 2011
    18
    1
    well, tab water differ from town to town and country to country, if the probes are large enough, they will be ok, but remember what thatoneguy said about ionization, the more current the quicker things go bad unless you use stainless steel or Carbon rods or anything that will not react chemically
     
  9. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    Large probes? Means how big?
     
  10. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    Most probably, I'm looking forward to implement similar kind of design. Anything to improve reliability will help. But the basic question remains....'will this work correctly?'
     
  11. Maged A. Mohamed

    Member

    Apr 6, 2011
    18
    1
    I can't say, either measure its ohm with DMM or try and measure the voltage across your circuit
     
  12. Maged A. Mohamed

    Member

    Apr 6, 2011
    18
    1
    if you insist on this design to improve reliability, use piezo speakers, they do not consume much power
     
  13. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    theres no reason why you cant run it at 6v.......but there are better ways to do it
     
    Last edited: Jan 4, 2012
  14. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    Yeah. But I already built similar circuit.
     
  15. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    A small modification for your alarm pulser. This works. Don't worry to much about the electrodes corroding due to electrolysis . They will only be in the water on the rare occasion of an alarm condition. I would still opt for stainless steel if continually exposed to humid conditions above a water surface.

    Are you intending this to be battery operated, or DC from a wall-wart?

    Ken
     
    Last edited: Jan 4, 2012
  16. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Get some non-flux coated stainless steel welding rod from a welding supply shop for electrodes. Cut into 12" or whatever lengths you need.

    Amazon sells them as well
     
  17. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Ask for stainless steel TIG rods at the welding store. Or just go to your hardware store and buy a small spool of ~20 gauge stainless steel wire.

    Ken
     
  18. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    That too. Remember to use alligator clips, as SS isn't really friendly to soldering with copper, and they need replacement once in a while anyway.
     
  19. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    I usually tin the end of the SS rod with a silver braze/solder. That way you can then soft solder (tin/lead) copper wire directly to it.

    Ken
     
  20. @android

    Thread Starter Member

    Dec 15, 2011
    178
    9
    I'm planning to use battery.
     
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