Hi,
I agree.
Simpler the better.
I don't see the point in sensing the extent of arc.
The point of a Foucault arrangement is to show the
rotation of the ground beneath our feet.
It could be that it is used in this arrangement as
some way of maintaining the swing, by operating some
system applying energy to the pendulum.
I would be interested to find if this is the case.
A typical home type set-up would have a string length
of about seven or eight feet, the point at the bottom
would typically travel about eighteen inches maybe a
bit more, over a sheet of paper with a circle marked
with maybe degrees, or compass points, or just hand
drawn lines.
The speed of the swing is usually very slow, in the
order of about three or four seconds per cycle.
(assuming normal ceiling height)
If this business is intended to make the pendulum keep
swinging, then i feel a simpler method would be much
easier.
If this business is not aimed at maintaining the swing
then i would be very interested in its purpose.
The method mentioned by mechie, using a short delay,
sounds about the simplest to me. It would involve
the use of an electro-magnet which you say you want
to avoid, but you would have to be quite innovative to
come up with an alternative.
It's been a few days now,
will we hear from Fried Circuit again ?
Regards, John