Hi
I am searching for a smart device that I can use to detect when a flush in the toilet has been “issued” that can send a signal to Homey so I can trigger a flow … My first idea was to use a water leak sensor (Like the Aqara water leak sensor) and place it in the toilet bowl, but I would have to fix it with silicone or something, which makes it hard to change battery, second issue is that over time it will become nasty.
Does someone have an idea on how I can achive this?
BR
Stig 
Er… Just thinking out loud here: depending on your flush button, a (small) contact sensor on the button itself might be able to do this? Does clutter up said button though, so definitely not the most sleek option.
Another idea might be a water usage meter, if you fiddle enough with it to find out how much water you use when flushing. That probably wouldn’t work in bigger households though, if e.g. another person is taking a shower at the same time you are using the toilet.
Maybe a tilt sensor, behind the button for your flush. I don’t have experience with the tilt sensor although i have one from aquara. Tried it on the door for the cat, but never got the angle for the flow to work properly . But probably the tilt could work for this.
Perhaps place a water leak sensor in the cistern? I believe that you can also attach two wires to the sensor (see “option 2” on this page) so it doesn’t have to always be submerged and might be placed at a more accessible location.
That would also be my idea. I use a Youless with pulse meter on my water meter. A toilet flush has a pretty distinctive usage profile. In most cases an advanced flow should be able to detect if a toilet was flushed.
Downside is you have to wait untill the flushing/water flow has ended. So that could take a minute. Secondly ‘noise’ from other water use could lead to sometimes missing a trigger, or to get false triggers.
Upside is that you do not need to mess around a toilet😉
Thanks @SortOfSmart , @Marcel_Ubels and @robertklep , those are all very good ideas …
I went to see on youtube how to disamble the model of toilet I have (Afmontering af Ifö Sign cisternekappe - YouTube) and after that I think the idea of putting a water leak sensor with 2 wires inside could work … but will the Zigbee signal be strong enough to go through the porcelain!?! …
The idea regarding tilt sensor is also a really good, idea I have one of these from Aqara, but they are to big to hide under the button on my toilet.
The idea regarding contact sensor, got me thinking … I do not think that a contact sensor like the Aqara (even though it is one of the smallest) will fit, but the idea is actually good … if I could get an “old time” push button (like this Mom. Switch SPDT 20VDC 20mA Vertical Lug | Elektronik Lavpris Aps (elektronik-lavpris.dk) and get it connected to a zigbee transmitter perhaps
I’m assuming you already thought of alternatives? I’m not sure what your exact use case is, but if you’re trying to determine if someone used the toilet, a simple pressure sensor under a mat might do. Maybe even a strategically placed pir sensor.
The use case is that I have a Rituals Genie (https://www.rituals.com/en-gb-dk/the-perfume-genie-2.0-1113375.html) that I wish to start whenever someone have been on the toilet to get a better smell in the bathroom … the presure sensor under a mat will not work since I do not have a mat 
Ah, I thought it to be something like that 
Still, detecting a flush might be the more complicated trigger for that use. Are you talking about a bigger bathroom (where one might also go to shower, shave etc.) or a smaller with just a toilet? If it’s the latter, detecting someone leaving the room might do as well.
Though I assume there’s a reason you went with flush-detection? Maybe it helps if we know your reasoning?
Use a methane detector to handle the use case when someone fails to flush 
the thought has crossed my mind 
Its a smaller bathroom, but it has both Shower, toilet and Washing maschine and Tumbler, so there could be several reasons why they are at the toilet. which is why I need the flush to trigger the flow
Fun idea.
Could you have a sensor for closing the lid.
Because you DO close the lid? 
Or motion sensor behind toilet, close to the floor so it only detects when you are really near the toilet.
Can’t you build a doorsensor on the inside of the flushing plates?
I do 
… not all do
Ahhh yeah that could be a Solution, I have to Think that through 
Just connect two wires to the water leak sensor and put wires in toilet
You could use this solution:
Not sure if it work but have you considered to use a vibration sensor?
https://www.elektroimportoren.no/aqara-vibration-sensor/94286/Product.html
Tore
