[Lab] Water sensor for an arduino?

[Michael Grant]

I'd suggest something entirely non-contact, with galvanic or capacitive
isolation.
If the water is in contact with ground or a live wire it could have a
potential voltage that will adversely affect the Arduino.

Something like this will work with minimal hardware:
http://playground.arduino.cc/Main/CapacitiveSensor?from=Main.CapSense#.Uzq6YFccDDA

Michael
http://krazatchu.ca/


On Mon, Mar 31, 2014 at 11:49 PM, Justin <justin at slootsky.org> wrote:

>   Awesome tips, thanks!
>
> On March 31, 2014 10:26:25 PM Jaime Yu <jaime.yu at gmail.com> wrote:
>
>> Hey,
>>
>> Sparkfun has some water level sensors which you could check out.
>> https://www.sparkfun.com/search/results?term=water+level. It looks like
>> their H20hNo! kit does exactly what you suggest so maybe you can gleam some
>> hints from their schematics. The distance between the 'nail sensors' will
>> have to be awfully close in so the voltage potential is enough so it can
>> cross the medium. Water isn't that great of a conductor and will probably
>> require some experimentation to get the distance right (ie: salty water is
>> much more conductive than distilled).
>>
>> --
>> Sincerely,
>> Jaime Yu
>> B.Eng in Computer Engineering, System Hardware
>> Software Developer III at Juniper Networks
>>
>> $CV = "http://cv.jaimeyu.com"
>> $Blog = "http://ask.jaimeyu.com"
>> $Project = "http://www.capstone490.com"
>> $Linkedin = "https://www.linkedin.com/in/jaimeyu"
>> $GitHub = "https://github.com/jaimeyu"
>>
>>
>> On Mon, Mar 31, 2014 at 10:48 PM, Tom Burns <tom.i.burns at gmail.com>wrote:
>>
>>> If that doesn't work, use two nails and a floating conductive ball to
>>> complete the circuit when the water raises.
>>>
>>>
>>> On Monday, March 31, 2014, Justin <justin at slootsky.org> wrote:
>>>
>>>> With spring comes flooding.
>>>>
>>>> I have a pump, but it doesn't have an auto shutoff, and it shouldn't
>>>> run dry.
>>>>
>>>> I have a powertail that I can use to turn the pump on and off, so now
>>>> all I need is a water sensor.
>>>>
>>>> Would this be as simple as two nails in a board with wires attached to
>>>> the nails? Water is conductive, when the water completes the circuit, the
>>>> Arduino notices and turns on the pump.
>>>>
>>>> Probably two water sensors, with the "on" sensor being above the "off"
>>>> sensor to prevent it from triggering on and off too fast.
>>>>
>>>> Is anything wrong with my logic? Why won't this work? Do I need more
>>>> than wires to make a water level sensor?
>>>>
>>>>
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