time delay switch

[Lacustral <lark@xxxxxxxxxxxxx>]

I'm looking for a delay switch for a bathroom fan and I haven't found any
that have exactly what I want -
- adjustable time interval from a few minutes to, say, 1/2 hour.  I'd
rather not get one that just has a few choices for time interval.  You can
get one that gives you 5,10,15, 30 or on-until-switched-off choices, but
I'd like to have it completely adjustable.
- time delay interval controllable on the outside of the faceplate
- doesn't make noise.  Spring timers all click as I've heard, so not a
  spring timr.

What the delay switch does, is you can leave the fan on after you leave
the bathroom, for an adjustable time.

The closest thing I've found is this:
http://www.rewci.com/fandetisw.html

It has a delay of up to an hour.  I don't know why anybody would want to
keep the fan on in the bathroom for an entire hour after leaving, but I
guess it's conceivable.  So I'd live with that.

But it's designed so the time delay adjustment is hidden behind
the faceplate, and changed with a screwdriver.  I want to have the delay
adjustment on top of the faceplate.  So there would be a sort of
screwdriver blade attached to a knob, anchored to the faceplate somehow.

Any ideas about how to do this, so it would work reliably?

Alternatively, I'm sure it's possible to get a circuit that will do the
delay function.  If the guts of it could be covered over so it looks nice
- I could buy a wood faceplate and cut circular holes in it for the
knobs - that would
also do.  It would have to fit in a gang box, or whatever they call the
metal box that switches are enclosed in.

Laura