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8 Feb 2018, 15:00

*WINNING ENTRY* LeakKiller Challenge Entry - Adamsky's water blocker

Dear DS.

Way back, when a water leak first damaged my flat and the flat below, I decided to do something about it. So I did. Forgive me for not sticking to the guidelines, but I created this solution way before the competition launched and decided to share with you. 

So, I created this system entirely for my personal use following a water leak in my home. After a few weeks, when my washing machine played up again, it proved to be well worth the hassle!

All the units were built on Arduino NANO boards using open source elements available on the internet (except for the motorized valve). All you can see in the picture was made for around £70. Obviously, the most expensive part was the valve (£30) but I've decided not to re-invent the wheel when there are proven parts available on the market.


Let's talk about functionality

Water probes used in this project are widely available on the internet for next to nothing. It's the positioning of them makes the real difference. Let's face it. It doesn't matter what leaks in the kitchen, it matters that it leaks. All of Master and Slave units read values from up to 10 units connected to the same controller on a length of cable up to 10m. Using ribbon cable and IDC connectors I'm able to locate them wherever it is necessary (washing machine, boiler, dishwasher, sink, fridge) and so on if we're talking about the kitchen. Using only one remote battery powered unit with chained probes we monitor basin, bath/shower, toilet. The single probe connected to the remote unit, monitors and controls supply to non-mains water supplied appliances like radiators and fish tanks.    

Master unit is a self-contained system itself, it does not require any additional slave units to work, unless under specific conditions, like water mains supply stopcock is away from the monitored area. It monitors water presence as well as high humidity. That gives us two different levels of protection. High humidity alarm as a slow water leak that could be stopped before serious damage and water detection to prevent extensive damage to property. The Master unit has a built-in rf receiver and rf transmitter as well as audible alarm and status LEDs. It doesn't act as a power disconnector, the enclosure I chose is purely keeping the existing appliance working without using socket space which may be dedicated to this appliance, i.e. a washing machine that just happens to be located next to the main water supply valve.

How the solution works



The Probe detects high humidity:

  • Status LEDs flashing solid green with red interrupting
  • Audible alarm beeps short signal every 1s

The Probe detects water presence:

  • Status led flashes green and red as long as valve did not shut and then red only when valve fully shut and water still present.
  • Audible alarm beeps long signal every 1s
  • Motorised valve shuts
  • Master unit sends information to (just because I'm using it throughout my house) LightwaveRF pre-programmed device like ceiling light in the bedroom, corridor and kitchen to direct to leak in case it happens during the night.
  • If no-one is present to attend the alarm (within 10 minutes) the relay within the unit shortens Neutral and Earth pins in the socket the unit is connected to, causing RCD to trip and cut power to this particular ring.


ready to reinitiate.

Master unit is fully fail-safe designed. It will not reinitiate the valve and the system even if power is restored and all probes are dry. Just as on the first installation, it requires the user to press and hold push button at the front of the unit for 10 s until the green LED stays solid and valve position switch feedback sends the signal back. The valve itself can be manually operated to open position in event of power failure and will automatically reinstate into automatic mode after control unit initiation. 

  • Status LED flashes short green every 1s
  • No audible sound
  • Valve stays shut

Power Slave

Power slave unit acts exactly same way as a master with a difference of choosing what to do in event of water detection alarm.

The probe detects high humidity:

  • Status LEDs flashing solid green with red interrupting
  • Audible alarm beeps short signal every 1s

The probe detects water presence:

  • Status LED flashes green and red
  • Audible alarm beeps long signal every 1s
  • If switch on front panel is set to local, it cuts the power to the appliance connected to it i.e. fish tank pump
  • If the switch on the front panel is set to remote, it sends rf signal to master to shut water supply and master acts as by (water leak detected) program.

Remote Battery Slave

Remote battery slave is designed to be used in non-powered and unsafe areas i.e. bathrooms. It acts exactly the same way as a powered slave with a difference of no option to control local devices power supply. It only alarms locally and sends rf to master to shut the water supply off if set to do so.

It also serves another purpose which helps with detecting central heating leaks from radiators or water storage tanks. Those are located in areas that we cannot do much about, even if we cut mains water supply off. However, it indicates the water presence so we can attend the issue before it grows into something bigger. 



I have been using this self-built kit for nearly two years and so far it has detected a toilet cistern leak and the earlier mentioned washing machine leak. It's a simple yet effective way of dealing with leak detection in the house.

As I got back to it thanks to this competition, I think I will upgrade it to remote water shutdown via the LightwaveRF app and email notification in event of abnormalities.

Kind Regards


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8 Feb 2018, 15:00