Hi All, I have a project and was hoping for some help here. I need to build a type of solenoid that will move a 3/4 inch diameter rod vertically about four inches and hold it there for a minute plus. This will have to be powered by a battery so energy use is a concern. I have an idea on how to do this but need some input regarding the feasibility (not an engineering major). This will not require any additional linear energy beyond just extending the rod itself. Since this would be outdoors with space limitations, I want to avoid using a motor. Would it be possible to: Use a permanent magnet (tube or disc) to hold the rod in the retracted (bottom) position with a compressed coil spring below suitable to lift the rod. Wind the permanent magnet to cancel the permanent magnets field and release/extend the rod using a DC pulse to the windings. Momentum of the released rod would carry the rod beyond the tube magnet (and spring) to a second smaller "holding" permanent magnet (also wound). To retract, a second DC pulse to the "holding" magnet would release the rod and allow it to drop into the lower permanent magnets field and be drawn all the way down and recompress the spring for the next cycle. The rod can be sectional (metal/plastic) and the target weight of the rod is about 3 ounces. Feasible?