Maybe the Sonoff team would consider producing a water level sensor. One that would be able to indicate that the water level in the container is too low, something like AutoAqua Smart Level Security, only without a socket and in the form of wifi/zigbee like DW2. It could even be a simple reed sensor, just a magnet, the water version.
The same principle as the valve in the toilet.
@Daniel_Zhan Looping Sonoff
1 Like
The max distance between the sensor and magnet is 0.5’', it seems the application scenario is limited, just for a fish tank or glass tank.
1 Like
We will launch a water leak sensor with an IP67 rating next month, it would be useful for your application purpose?
2 Likes
Perhaps, a lot depends on how it will look, work, have functions, and whether it will be cheap or quite expensive.
A typical water leak sensor may not work well, however, because it would have to be submerged all the time and react not to water but to its lack, and at the same time distinguish between humidity and a large amount of water.
My case is a large plastic tank for clean water. There is a pump at the bottom that must/can only work when fully submerged. The pump is connected to S26R2 and remotely started, after turning it on it will work until it sucks all the water and seizes up, running dry.
The sensor was to be mounted above the water level needed by the pump and when the water level in the tank dropped, it would turn off the pump before it started running dry.
Currently, I do it using flow + time, but it is not very accurate because it is calculated for the maximum flow/operating time and sometimes the throughput is lower, which causes it to be turned off too early. 
I considered many concepts based on many solutions, but at the end of the day it must be something cheap and simple in a general sense and be compatible with ewelink/sonoff.
instead of a pump, a wifi sensor would be connected…
Aqua-Trend Samudra Level Control SP
Type sensor instead of a magnet permanently connected to DW2.
connect the sensor to the sonoff MINIR2 or ZBMINI terminals.
Sonoff MINI will directly control the pump. It does not require an Internet connection.
I am considering such options, among others, but S1/2 probably have some voltage?
MINIR2
has 3 voltage
1 Like