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Topic: Water on the Floor Detector (Read 9174 times) previous topic - next topic

Delta_G

Can anyone recommend a good sensor for detecting water on the floor?  I need to be able to shut a pump down if a leak is detected so I don't flood my house.  Bonus points if it is something that can easily DIY.  I was thinking of using two wires closely spaced and checking for continuity, but I don't know how reliable that would be.   
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larryd

#1
Jan 17, 2015, 05:52 pm Last Edit: Jan 17, 2015, 06:48 pm by LarryD
For the sensor, two bare wires placed in different holes in corrugated cardboard.
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pwillard

#2
Jan 17, 2015, 06:11 pm Last Edit: Jan 17, 2015, 06:12 pm by pwillard
This makes a good "water on the floor" sensor.

leaf wetness sensor

Boardburner2

I used a 5 kit from maplins as a leak detector under my sink.
Was a kit i think

jremington

I use a piece of PCB with fingers, like this one: http://www.circuitstew.com/pcbs/water_alarm.html
An Arduino is certainly overkill as you need only about four parts to make a very reliable leak detector. Google "water leak alarm circuit" for thousands of possibilities.

Delta_G

Thanks for the suggestions.  So it doesn't look too hard. 


I use a piece of PCB with fingers, like this one: http://www.circuitstew.com/pcbs/water_alarm.html
An Arduino is certainly overkill as you need only about four parts to make a very reliable leak detector. Google "water leak alarm circuit" for thousands of possibilities.
The arduino is already involved.  It's the thing deciding when to turn the pump on and off in the first place. 
|| | ||| | || | ||  ~Woodstock

Please do not PM with technical questions or comments.  Keep Arduino stuff out on the boards where it belongs.

MorganS

A float switch is more reliable than wires. The DC current through the wires will corrode them relatively quickly. You may need to build a dam around the pump to get a deep enough puddle for the float switch to float.

Sump pumps and bilge pumps do the opposite. (Turn on when water detected.) Perhaps their float switches are available separately?
"The problem is in the code you didn't post."

larryd

#7
Jan 17, 2015, 07:30 pm Last Edit: Jan 18, 2015, 09:36 am by LarryD
Quote
A float switch is more reliable than wires
Not if the wires are always dry ;)
If it is just for an alarm then you simply replace the cardboard sensor as needed.
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raschemmel


Coding Badly


Delta_G

A float switch is more reliable than wires. The DC current through the wires will corrode them relatively quickly. You may need to build a dam around the pump to get a deep enough puddle for the float switch to float.

Sump pumps and bilge pumps do the opposite. (Turn on when water detected.) Perhaps their float switches are available separately?
Yeah, it's just an alarm.  I have a float valve at the top of the tank that physically stops the flow to prevent overflow, but I don't have anything to detect water on the floor starting to puddle if I had let's say a leak in a hose like the one I had this morning.  Even if it has a 50% chance of working, that's 50% better chance that I don't do this again.  I like those odds. 

|| | ||| | || | ||  ~Woodstock

Please do not PM with technical questions or comments.  Keep Arduino stuff out on the boards where it belongs.

raschemmel

Quote
I've used this ic before. It works great.
Quote
At 5V?   
No.  It won't work at 5V. It requires 16V minimum.

Delta_G

I've got 5V and 12V DC and 120VAC, but no 16V.
|| | ||| | || | ||  ~Woodstock

Please do not PM with technical questions or comments.  Keep Arduino stuff out on the boards where it belongs.

Paul__B

For the sensor, two bare wires placed in different holes in corrugated cardboard.

Plausible circuit - almost - but why do people always dash off something straight from "Electronics for beginners" rather than thinking about the design?

Having one sensor terminal connected to 5V is just asking for corrosion to occur, and for the device to fail if either or both sensor wires are more strongly conducting to ground (such as perhaps - a floor?) than to each other.  At least the 1k resistor prevents such a short to ground from affecting the power supply itself.

The more appropriate circuit would have the sensor between the input terminal (of the Arduino directly would be OK if isolated by a 47k resistor) and ground with a "shunt" resistor to 5V of 47k or so.  In fact, that "5V" could be provided by another Arduino pin which was only pulsed HIGH occasionally when necessary to make a reading, and the sensor connected only via a capacitor (maybe 1µF, ceramic or plastic) to remove any DC current which could cause electrolysis.

D-question-mark?

larryd

Quote
dash off
If it's beyond ones  capability they can decide to do otherwise.
This is under General Electronics.
I thought this was a place for idea exchange.

I have used this cct. for years.
I have experienced zero corrosion as this is a dry sensor (until there is an alarm, then you exchange the cardboard). There is no electrolysis.
The cct. power supply is from a wallwart isolated from earth.
The cct. is designed like this to support long cable lengths (some of mine are 30+ feet).
I have used multiple sensors attached in parallel to the same input point.

Quote
The more appropriate circuit . . .
Offer what you want.

I didn't realize this was a contest.
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