I was browsing through my Youtube uploads and came across these two old video's. I'll share these, just for fun.

One of the projects in my bucket is a 'leave me alone machine' with all six servos daisy chained. A bit in the spirit of the device in the next video. When working on a project for a small contest I accidentally discovered the auto-switching feature. This is the result:

This was the first project I made with this sort of servo controlling

Makes me smile every time I see it.

There are three simple ne555 based control boards for the servos. the led is switched by setting and resetting a flipflop.

I'm not really sure any more how it's wired, but there are two switches on the upper arm, one on the end and one operated by adjustable stoppers on the upper rod.

the upper arm itself is fixed to a servo and also rotates around (and is partly supported by) a potentiometer shaft. The position of the shaft is fixed, and the pot body rotates with the arm.

The rotation of this pot controls a servo and sort of acts as one half of a multiway 'switch' (not sure about the name, but wikipedia tells me it's a traveller system) where the wiper is the hot lead.

I dug up a schematic for the controller, the pot is RV2.

iirc R3 is a pot too, adjusted for a waveform with a ~20 ms cycle. RV1+RV2 control the length of the high part of the pulse. RV1 is a multi-turn pot adjusted to locate the servo position.