I followed the switch machine project with much interest but needed something simpler for my situation. I don’t run track power so I just needed something that would throw the switch both with a manual lever and allow computer control via a servo. I got to thinking what I really needed was a ‘clutch’ of some sort so I came up with this design. Two magnets on the servo wheel and one on the control lever. I’ve got it working on the bench and it seems effective, you get a nice ‘snap’ with the magnets but they are not overly strong so they act ‘springy’. When the servo has control, you can rotate it and ‘catch’ the lever magnet to throw the switch. Simple and super cheap. The servo is a waterproof unit but was only about $5. The styrene was scrap and the wire is a paperclip. So now on to testing in the garden and see how it holds up in the spring rains…
Some pictures here:
