I know that there was a type of unit that used a torsion suspension, I 
saw it in an old Scientific American magazine.

A small post held a wire vertically between two clamps, the top clamp 
being adjustable to set the zero.
It used a small copper 'flag' that mounted to the wire, and had a mirror 
mounted on the flag.
There was a magnet mounted to damp the flag, which was the pendulum.
The readout was via a light beam onto a photopaper covered drum.
There were two little rods with slots that held oil drops to help damp 
the wire.

It's in that CD that has the collection of all of of SA's Amiature 
Scientist columns.

I'm not sure why this type went out of style, but I remember some 
discussion on this list a long while back about it's shortcomings.

Hope this helps,
Daryl
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