The one that got away…
you cant win them all. or..can you? whatever the case, this is the one that got away in favor of the sl-1200mk2 cue lever auto lift. this was the first rough version i cobbled together as proof of concept.
i used a piece of aluminum tubing and for the cam, an aluminium rod cut down to size. with nothing more than a dremel, making the holes in the cam to fit the brass bits was rather difficult and without a vise and a jig of sorts is a pretty scary affair. i value my fingers… it took me about an hour with a dremel to cut out all the pieces after i had the design down on paper…its much easier to put together with the proper tools. it would also benefit a great deal from having better tolerances instead of my prototype straw sleeve. the mechanism is obvious enough. the proximity sensor would sit on the brass arm and when triggered/detect the tonearm, will raise the cam and the brass arm. the reason the arm is so long is that its heavy and the offset weight caused binding between the tube and the cam. balancing it off on the other end helps prevent binding and provided a smoother mechanism. the servos been slowed down to prevent it flipping the tonearm up causing it to bounce.
now…, to what ive learnt from this. while this works, theres a problem. if theres too much weight on the arm, it causes the servo to jitter as it pushes against the strain once stopped in the up postition. obviously not a good thing. a servo with more torque may help. but the solution would be to use the servo arm as a cam instead and in the up position should be pushing straight up in a 12 o’clock position preventing any strain on the servo avoiding jitter. that would also mean a total redesign and fabrication… for another day.
i dont really have a use for this, just to share. i prefer to tie the mechanism in to use the existing cue lever.. makes it a more elegant solution but also table specific.