Quote Originally Posted by nhengineer View Post
Good suggestion, Sleykin. Any idea where I'd get a doughnut shaped float to fit through a 1.6" diameter hole?
As Marv said, about any float that isn't eaten by oil will work fine. I have lots of different magnets that would work fine. You would want something on the bottom of the tube to keep the float from falling off the end if the level got too low and also so the float won't drop below the last reed switch. The reed switches would be normal open switches. One switch at 1/2 full and another at 1/4 full. The one at 1/4 full would be the bottom of the plastic or copper tube and would stay lit until the tank is filled. The circuit would be a simple 3 wire 2 AA batteries would operate it just fine. So, all you would need are 2 reed switches, 2 LEDs, the float and magnets and a tube and some wire. I was thinking 3/8" tube would be ideal and the float would not have to be a large diameter. Do you have a lathe or drill press? You could easily make a float out of anything floaty