Re: Variable speed wall clock
- --- In Electronics_101@yahoogroups.com, "grantfair2001"
> At $15.95 this is the cheapest kit solution for a variable speedhttp://www.mpja.com/category/MPJA_Kits/UNIPOLAR_STEPMOTOR_DRIVER_KIT_8479_KT.asp
> unipolar stepper controller I know of:
>I have heard good reports for that driver. it is full step, but for a
> Speed may be varied by an on board pot, or by externally applied
> pulses. In addition to the kit it does need two separate power
> supplies, one for the controller and one for the stepper.
clock, that should be fine.
It is also available for $13.95
I'm not sure if it would be easier to make a clock movement or to add
onto one. the gearing would be 12:1 no ?
> --- In Electronics_101@yahoogroups.com, "mcgyver42y" <mcgyver42@c...>
> > I have the need to create a prop for a theatrical production. This
> > prop is a large wall clock that must run at variable faster-than-
> > normal speeds. The speed should be controllable remotely by the
> > lighting operator, and should be variable from 1 to 4 times normal
> > speed.
- I'd just try running some bell wire from the clock to the control
--- In Electronics_101@yahoogroups.com, "Dave Mucha"
> --- In Electronics_101@yahoogroups.com, "Chris Wardell"grounded
> <ctwardell@w...> wrote:
> > Dave,
> > The cap is how the positive and negative pulses are achieved.
> > When OUT (of the 555) is low, the cap is discharged because the
> > positive lead is at (near) ground and the negative lead is
> > via the coil. When OUT goes high, the coil momentarily sees Vcccoil
> > while the cap is being charged. When OUT drops low again the
> > sees -Vcc because the positive lead of the cap is now at grounddischarged.
> > driving the negative lead below ground while the cap is
> > The cycle then repeats...through
> > This also results in a slow decay across the coil, so no diodes
> > needed.
> > The biggest issue is sizing capacitor so enough energy flows
> > the coil during charge/discharge to move the actuator.
> > C.W.
> I missed that part of the control sequence.
> my bad.
> What to do to handle the 150 foot run ?