I was thinking about wind powered noise makers. One could use a cylinder turned by a windmill, like a music box. That would be nice, and would loop indefinitely. However the mechanism would not do well at reproducing voices. Too 19th century.
One could use a windmill-charged battery and a chip that spoke a message. Too 21st century.
What about a wind turned record player? That would do well with voices. But the problem is the end of the record. How to make it loop? You could have the needle arm come up and off and move back to the start but that would entail a pause and a whole seperate mechanism. Fussy.
The solution: a toroidal phonograph record. The track wends over the toroid, ultimately ending at its beginning and so the recording is played over and over without breaks. As the needle progresses the toroid rotates around its long axis (long if it were cut and stretched into a cylinder). There are toys that do this: toroidal bags full of water that are very hard to hold as they slip from your hand. Something of this sort would work with some interior support to fortify the upmost surface currently being played. Alternatively the toroid could be broken into segments, which could be firm like an LP record, although the needle might skip when jumping seams.-- bungston, Oct 04 2009 Very good. Could you make a material that would expand and contract many times without appreciable distortion though?-- 2 fries shy of a happy meal, Oct 04 2009 /distortion/ If the toroid were flexible plastic it would probably not be as durable as an LP. If it were segmented you could make it out of aluminum or carbon fiber or LP vinyl but skipping would be an issue.-- bungston, Oct 04 2009 If you placed the needle along the inside of the toroid, at the point with the smallest diameter, you could use rigid segments. The edges of the segments would pinch together and align at that innermost point. This would also eliminate any decay or distortion caused by the audio groove being stretched as it rotated to the outside of the toroid.
You could still use gravity to hold the needle in place if you positioned the toroid vertically, rotated it like a wheel instead of a turntable. The segments could be fixed around a coiled spring to hold them in place, and rotated by setting the whole assembly on wheels running along the inside of the toroid.
In this position, the action of the needle in the groove might be sufficient to cause the toroid to twist naturally. If not, another wheel mounted on a 45° angle to the toroid could assist with that motion.
The other solution to your looping problem is just to use a short continuous track, like the inner groove recording on Sgt Pepper.-- tatterdemalion, Oct 05 2009 Run the needle on the inside of a cylinder, in a screw-thread style pattern. Have a second screwthread running in the opposite direction. Rely upon momentum to ensure that the needle keeps going in the right direction, and have a little tab that pushes the needle inward at each end to give it a start. For bonus points, have the track curve just before an intersection to give a bit of added acceleration to the needle as it jumps the cross.-- vincevincevince, Oct 05 2009 / along the inside of the toroid/ I like it. Even trying to think outside the box I still imagined the toroid sitting flat like an LP record.-- bungston, Oct 05 2009 random, halfbakery