On Tue, 20 Nov 2001, Gareth malham wrote:

> try again? http://malcam.fucx.co.uk/ just checked it

No ... still am getting a name lookup error.  Don't know why.

> Well the idea is to be able to record a day from midday to midday in a 
> single flat image with a view to capturing the movments of tides.

That could be interesting.  I'd certainly like to see the results when you
get this working!

> I'm unsure about stepper motors and what they do? Any good links would be 
> appreicated

It is a motor that rotates a certain amount depending on the application
of a pulse or a binary code.  There are lots of designs, the simplest
being a ratchet on a shaft driven by an electromagnet.  Usualy though it
a motor designed without a commutator.  You energize the coils and the
rotor rotates until it aligns with the field coils.  If you treat the
field coil switching as a binary code you can drive the motor by sending
it a string of binary coded words.  Figured if you were already planning
to use an embedded microprocessor this might be a good approach.  That way
the microprocessor has control of the motor speed and length of rotation.

You can search the web for stepper motor info.  One URL I dug up that
looks pretty good is:

   http://www.cs.uiowa.edu/~jones/step/

> Just a simple PIG processor

Not familiar with that one.  Don't suppose you have a URL I could look at?

> which will read voltage from a photo cell inside the camera and adjust
> the pol filters to keep nthe voltage constant, this is somthing which
> my father, who is an electronic engineer will help me with.

Sounds like a servo motor with an analog lead/lag feedback control might
be more apropos.  It would at least eliminate the need for A/D sampling
and the possible need to do D/A conversion for your servo control (unless
you used a stepper motor).  Of course noise could be an issue.  Either way
should work.

- Wayde
  ([EMAIL PROTECTED])

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