[Renzo Mischianti]’s friend has to keep a water tank topped up. Problem is, the tank itself is 1.5 km away, so its water level isn’t typically known. There’s no electricity available there either — ...

Sometimes we need a non-contact liquid level sensor. There are several ways to build that, but the easiest is to try an optical liquid level sensor. You may already have an idea in mind since you are ...