Leak sensors/moisture detection

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SumnerBoy

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#123196 27-Jun-2013 21:17

I would like to hook up a leak/moisture/water alarm to my home automation system (openHAB). I have a Raspberry Pi setup with the PiFace extension board so all I need is something that will close a circuit in order to detect the event.

I want to set it up by my underfloor heating manifold which happens to be right next to my hot water cylinder, so that I can detect if there is any water leaking from any of the plumbing etc.

Obviously I could just dangle a couple of exposed wires rest them on the ground and hope the water pools enough to short the two wires, but I was hoping for a more elegant solution.

Anyone know of any sensors/devices that would be useful here? Don't want to spend much, am hoping there is something simple out there I can use.

Cheers,
Ben

Niel

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#846953 28-Jun-2013 22:23

This assumes the water sensor measured to 0V as common. It should still be fine if it senses to Vcc, but at some point you might end up shorting something out as e.g. your PC is also earthed. Better to mod a sensor to measure to 0V.

The metal manifold will be essentially earth, so hook your water sensor 0V wire to it (or any metal plumbing). Then for the signal wire run some electric fencing wire (maybe polywire?) zig-zag through the floor wherever you want. Wherever water leaks you will have a path back to the water pipe, so only one sensing wire is needed.

You can never have enough Volvos!

LennonNZ

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#846974 28-Jun-2013 23:26

http://www.surplustronics.co.nz/products/2614-copper-foil-tape-adhesive-backed

You could run 2 strips of these really close to each other on the Floor and when water goes over them it will make the circuit.

SumnerBoy

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#847765 1-Jul-2013 16:07

Niel - not sure that would be the most reliable solution. If my manifold started leaking - it is sitting 300mm off the ground - water would drop down to the floor and pool but it would not necessarily be grounded.

Lennon - thanks for that - not a bad idea at all. I was hoping for a more portable/non-permanent solution but based on the lack of options out there, this might be the only decent option!

Niel

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#847773 1-Jul-2013 16:29

Oh, thought the manifold is on the floor. Oh well, would work for a pipe leak though.

You could use Veroboard cut into strips 2 tracks wide as your sensor. Suggest you get the tinned version as copper will oxidise badly.

You can never have enough Volvos!

SumnerBoy

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#847778 1-Jul-2013 16:40

Veroboard - great idea! I can only find the copper stuff though (http://www.surplustronics.co.nz/categories/32-prototyping-pcb-solder-breadboard). Any suggestions on where I could find some tinned versions?

msukiwi

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#847797 1-Jul-2013 17:24

I have one of these in my HWC (Since we had a Rheem cylinder have a seam failure!).
http://www.jaycar.co.nz/productResults.asp?keywords=LA5163&keyform=KEYWORD&SUBMIT=Search

Only stops the alarm if you switch it off.
You could use as is standalone or modify the circuit to trigger your automation etc.

Dell

Shop now for Dell laptops and other devices (affiliate link).

Niel

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#847798 1-Jul-2013 17:28

Should be able to find it at Jaycar, also try Element14 (if you buy enough stuff the postage is free).

You can never have enough Volvos!

SumnerBoy

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#848042 2-Jul-2013 08:23

Thanks guys - I think I will just try a home brew solution first and if that doesn't work, look to some of your suggestions. I am thinking a piece of cardboard with two pieces of alu foil glued on, something like the attached picture should probably do the trick. I will hook up the sensor to my PiFace board on my Raspberry Pi and use that to detect closures.

SumnerBoy

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#928113 6-Nov-2013 12:52

Just a short update - whilst my home brew sensor has been working quite nicely, today I upgraded to the new Fibaro Flood Sensor (FGFS101). It is a great little device, reporting battery levels, temperature, as well as flood alarms and tamper/motion events. All for $150!

The more I use these ZWave devices the more I am convinced it is the way to go with home automation. Once you start to get a few devices spread around your home the mesh networking really starts to work. And Fibaro make some very nice gear - well made, feature rich, and everything 'just works'.