Anyone familiar with this 3 pin optical liquid level sensor?

[new-arduino-account]

Hi, Thanks for the answer. Sorry about the late reply. I ordered the 4 pin version (I'm still waiting for it) and wasn't monitoring this thread.

I think you are correct. Unfortunately, I can't verify it since I most likely blew it by applying 5V without the current limiting resistor. It explains the initial current draw as well. Now it shows OL between red and black in diode mode. Thing is it sometimes work with the configuration they show here, but results aren't consistent.

Shall I mark this as the Solution or should I wait for confirmation from someone else?

[jcvowles]

Hi, I cant be certain but I think that the 3 wire sensor shown below is a slightly different variant again and probably has internal current limiting resistors already installed. The capacitors shown in the suggested circuit I think are just 'good practice' decoupling caps.