Taidacent Mini External Sticker Intelligent Non-contact Electronic Water Level Sensor High Low Level Output Liquid Level Sensor Switch for Water Tank Fish Tank

Not sure why these are $10 each, seems more like a $2-3 item. They do work and are easy to connect to MCU. I bought a couple different kinds for testing, but my project requires 25 of these sensors. Will go to AliExpress for the rest - it’s cheaper there.

I purchased 1 and it worked fine. It sinks about 5mA when the sensor is not near water and nearly 0 when it is near water. The instructions gave some nice example circuits for wiring an LED or a microcontroller. I did notice it is possible to have it not quite turn off all the way (it normally conducts until it is near water) if the wall of your water container has some drops on it. From a practical standpoint the implications of that are obviously project specific. For the most part it turns on and off quickly with no time spent in the linear region, straight to saturation.

I am using a Raspberry Pi Pico W (ADC inputs), so I can broadcast the level of my boats water tank.As the title says, I had to reverse the polarity (blue +5v, brown gnd) on the two sensors I bought to get anything at all from the black OUT line.Now I don't know if the sensors are just going to break over time because it says don't reverse..I tried the given circuit with an LED, and nothing at all happened.Also, the cables are very short, so I'll have to mount everything really closeI wouldn't buy these again.

Non-contact

I like the fact that the simple documentation in the description is all that is needed. I connected the output to an ADC port on a raspberry pi pico, and it worked perfectly. I did have to use a logic level converter (3.3v, 5v), since the pico is a 3.3v device and this is a 5v device. I use mine to control a pump to fill a coffee machine reservoir.UPDATE: Bumping down to 3 stars. Over time it has become unreliable. It will often not catch a change in water level, either up or down. This results in the container emptying completely or over filling. When it works, it is great.

The form factor was really good but ... I ordered two (one high water level the other for low water level) and had no trouble on first test. I used very well regulated power for testing and the second test run (thinking all was good) was a disappointment in that one of the sensors simply didn't work. I returned it without issue thinking that it isn't totally bad that one would have trouble. The replacement came in and out of the box it was bad. I returned them all and bought a different model - same company !! - and they arrived and just work. So they seems to be conceptually good but the mfg may need to have a quality engineer hired.

I hooked it up as shown in the instructions and held it against a half full soda bottle. I powered it from usb. I hooked my volt meter to the blue ground and black output and got 5.3 volts when it was over the water and almost zero when it wasn’t. Bit then it suddenly stopped responding. I checked everything and tried again and it worked for a few seconds and now it reads 5.2 volts no matter what I do. The instructions provide an email addy for Bill. I haven’t heard back bit I will update if this has a happy ending.Update:I heard back from Billy. He said the unit failed because I used USB to power it. He claimed his engineer said USB is unstable. I did some research and found this:USB ports as a power source can be useful in prototyping simple circuits including those using the Arduino, micro:bit, and the Raspberry Pi. Devices powered by a USB port will most likely not require a special power conversion or regulation stage as USB power is typically very stable.

Use this to monitor the black water level in a marine holding tank. Used a 12vdc to 5vdc power converter with a 5V One Channel Relay to turn on a led light when the tank is near capacity. Very cost effective.