leak sensor that sends text message

Hi All,

I travel a lot and my upstairs neighbors have a shower that leaks onto my dinner table :-( When i'm present i can go upstairs and tell them to fix it. But when i'm gone :-(

so i was thinking of making a water drop detection (please tell what sensor do use) and then sending me and the upstairs neighbor that it is leaking.

please tell me detailled which components i need to achief this.

thanks a lot

If you rent, you need to tell the landlord to get it fixed. If you own the property, tell the neighbor that he will be taken to court to get any damage from the leaks settled. sometimes registered mail is handy for proof of notifiction.

thanks for stating the obvious :P

they fix it, but it is an old apartment and keeps breaking, but explain me how i can say to the landlord to fix it if i'm not there?!

That is the reason for the whole project!

xcraft: thanks for stating the obvious :P

they fix it, but it is an old apartment and keeps breaking

The obvious needs stating more clearly since you still seem to be missing it: if they 'fix' it and the problem returns, they have not fixed it properly. Every time it leaks this will damage the property you're in. Having recurring leaks in a property is not acceptable either as an owner or an occupier. The correct solution is not for you to get a more efficient way to tell them the leak has come back - it is to put the onus on your landlord (if you rent) or the landlord above you (if you own) to actually properly fix the leak.

Or, carry on with your head in the sand, put a bowl on the table to catch the drips, put a spoon of salt in to ensure it's a conductor and put two wires in it connected to an arduino to measure the resistance, and raise an alarm as sooon as the resistance drops - and continue to let them walk all over you.

to make long story short. the landlord is going to remodel the above apartment but is waitting for the 3rd floor to vacant to do them both. So he doesn't want to waste any money.

So salt and wires will work as a sensor?

A quick measurement here shows that two wires dipped into the local water produces about a 1M resistance. Adding salt brings it down to about 400K.

Even without the salt, using a voltage divider I could get reliable detection of dipping the wires into water:

void setup ()
  pinMode (13, OUTPUT);

void loop ()
  digitalWrite (13, digitalRead (2));

I put a 3.9 M resistor between pin D2 and Gnd, and connected the sensor wires thus:

  • +5V
  • D2

Theoretically that should give 4V on D2, and that is enough to turn it on. Or you could use an analog port for perhaps more sensitive readings.

Could you scetch me a diagram please?

thanks a lot

xcraft: the landlord ... doesn't want to waste any money.

Yes, wires dipped into water that is not pure will provide enough conductivity for you to detect. It's unlikely that dirty water that has then been drained through the structure of the building would ever be pure, but if you did run the same test with de-ionised water the conductivity would be much lower.

And your landlord may not want to waste money, but he still has an obligation to prevent the leak not just to 'fix' it every time it happens (in most countries, this would be a legal obligation not just a moral one). Obviously his interests are opposed to yours - he just wants a quiet life and as much profit as he can get away with - but you do have the right to require him to actually fix the problem. He does not have the right to make you endure water leaks for months or perhaps years until some third party decides to move out. If it costs him money, that's his problem not yours. He's running a business, this gives him certain responsibilities, fixing problems like this is one of them.