Gravity Non-contact Liquid Level Sensor

The sensor is good if you want to use it to sense the level of water for very thin surfaces. For instance, it will indicate water level in a cup. However, it does not work if the wall is thicker. It did not work for a 1/4 thick glass.

This liquid level sensor exceeded my expectations. I'm using it for wine level detection when bottling. What makes it outstanding is the fact that it is able to detect the level even though the neck of the bottle is not flat. And the customer service is outstanding, so I give it a rating of 5 out of 5.

While the sensor and interface are intended for boards with a minimum 5v input (and 5v supply), input into a 3.3v board (eg. Arduino Due) can be done by powering the sensor with 5v and placing a 33KOhm resistor from the output to ground, which then forms a voltage divider with the internal 20KOhm resistor in the sensor module. Additional detail can be found in the discussion here: https://www.robotshop.com/forum/post-p128300#p128300

This sensor works well for my project to detect when water level reaches the bottom of a tank in order to protect a submersible pump from running dry. I was concerned that the heavy plastic tank would be too thick, but seems to work perfectly.