D2CS-H Non Contact Type capacitive Water Level Sensor Easy Mounted Long Working Life Level Indicator(Pack of 3)

First impressions are that it works great detecting very pure R/O water through the side of a 5 gallon plastic bucket on a 5V power rail using a MEGA.

Work great for my arduino. But make sure that the circle is on the back. I thought it was the sensor side and hot glued them all to some aero gardens that I set up to auto water. Once I righted the sensors, reads well. Pretty much 4.77v or .1v. Now I’m eyeballing my coffee maker! lolps. after a month or so. one sensor pulled arduinos voltage to near zero. not sure why. two others are still working well.

Was super confused when I first opened them, came with 3 sensors but 1 control board or "MCU" as the "documentation" calls it. Plugged it into the board as shown in the video and did not work. Nowhere does it say click the "KEY" button on the "MCU" to change it into MODE2, which now they work. After very little tinkering, these work fine at 5V and 3.3V supply / logic levels directly wired to an Arduino, Pico, Teensy, etc. Not sure what the purpose of the "MCU" is for if nothing other than initially testing the sensors. Was awesome it comes with plugs for a PCB you can use in your own project that is not fitted to the "MCU" card, that way you can solder them to your project board and unplug them as needed to move stuff around or what have you. They are SUPER sensitive, I also can not find any adjustment screw that is mentioned anywhere about these things. BTW, if yours come as Red, Yellow, Blue wiring, its (+) Red, (S) Yellow, and (-) Blue. Did not take long to figure that one out and luckily plugged it in properly the first time and did not damage it at all from reverse polarity. So again, great product, just really horrible documentation.

I have had 2 of the 3 fail. Using in salt water tank refugium. They do get fully submerged from time to time and I am wondering if that is what kills them or if they just aren't reliable. On the 3rd one now. Time will tell.