I'm a junior at my university in electrical engineering and we're tasked with created an original project for my electricity and magnetism theory class. I've come up with something I want to do, however a fair amount of the design for this project is pretty far out of what I know how to do. Anyway, I'm working through a particular part of how I could accomplish this project and was looking for some people who are more trained in this than I am to look over my idea (and perhaps correct me if I'm going the wrong direction). One of the main parts of my project is that a weight will be raised, held, and lowered. I have the raising and holding design figured out for the most part, but for the lowering part, I am stumped as to how to go about the problem. I want the weight to be lowered at a low speed, as in, when I release the brake, I don't want the weight to drop as fast as gravity will take it. I am looking for a cable reel which can spool (or raise the weight) unhindered, but when it unspools (lowers the weight), I want it to release at a slow rate (preferably constant rate). I'm a bit uneducated when it comes to the world of cable reels, so I was hoping someone around here may have an idea of what can be used. My original thought was getting a cable reel and then attaching a bike brake or something and have the release regulated like that. My only reservation is that the brake doesn't require any electrical power to operate Any thoughts?