My new workshop is in my basement. For the hand washing / board cleaning “corner” this has the disadvantage that it is below the sewage level. In order to drain the water it needs to be pumped up. I had a few pumps from old washing machines laying around and decided to do some experimentation with this.
To make it easier for the pump (and to spare my back) I made a frame underneath the cabinets to raise the whole thing by 20cm. This way the water needs to be lifted less.
Normally there is a siphon after the drain in the sink, this part I have taken out and brought the pipe directly to the pump.
At the pump side the pipe goes down a bit in order to make the check valve work better (Picture further down on the page). Also because of this the sensor is not mounted at the lowest point. This makes it work better since the pump does not clear all the water from the pipes. The water that does stay in the pipe may false trigger otherwise.
However this means that the pump needs to operate longer when the sensor signal go’s off. Therefore I made a timer box. This was made with a Siemens LOGO The time is settable by a rotary switch. This switch is connected with a few inputs of the LOGO.
The timer box:
The program in the LOGO!:
To detect the water in the pipe I used a E2K-L26MC1 capacitive sensor from Omron. This sensor can be clamped around the pipe and does not come into contact with the water.
The sensor cheapest supplier for this sensor, I found on AliExpress.com: – Omron Level Sensor E2K-L26MC1 (Click-able Link)
This sensor has an NPN output, while the LOGO is only compatible with PNP output sensors. This I solved by adding a 10K pull-up resistor between out and +24V. After this the input needs to be inverted in the LOGO to work correctly (B17 in the program above).
Picture of the box and sensor installed: