Contactless water level sensor

Can I use this without the arduino. I just want to turn on an led.
I thought it might be like a motion sensor 5v. Gnd. And 3v out when motion is present

yes you can. the sensor can output up to 50 mA, which is more than enough to light a small LED. Be sure to include a current-limiting resistor so you don't burn out your LED. If you need more than 50 mA, then you'll need to use the signal to switch a mosfet or transistor instead. You could also use the output to drive a relay if need be.

That sensor has an LED built in.

It's not a motion sensor, it's a capacitive sensor, reacting to a change in capacitance (which is what happens when water instead of air is present in front of the sensor).

wvmarle:
That sensor has an LED built in.

It's not a motion sensor, it's a capacitive sensor, reacting to a change in capacitance (which is what happens when water instead of air is present in front of the sensor).

I think the OP meant "like a motion sensor" in the sense that it runs on 5V, and outputs a logic-level signal.