Re: Controlling Holiday Lights

[sylvan butler <ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 21 Oct 2006 21:35:52 -0400, Robert L Bass <robertbass1@xxxxxxxxxxx> wrote:
> some info about MIDI.  The protocol allows an instrument (or sequencer) to be controlled by "clocks" or "ticks".  48 clocks are sent

I know that.  I'm building the instrument that is controlled, not the
controller...

> that a "change" can be a command such as "Begin fade from scene 125 to

And the instrument which actually implements the fade is what I am
building.  Unless it uses HUGE variable resistors with HUMONGOUS heat
sinks to dump the waste heat, it will use PWM (Pulse Width Modulation)
to actually fade the light.  PWM requires switching the light on and off
very fast, otherwise you will see flicker instead of fade.

That is what I am building.  It isn't anything new.  It is just
phenomenally cheaper to build, plus I get exactly what I want.

> might also want to Google the archives of CHA using "Christmas lights"

Yup.  I've posted a few myself.  Such as
http://www.computerchristmas.com/ just a few days ago and almost exactly
two years ago.  :)

> or some such.  There have been a number of interesting threads on the
> subject every year since I've been posting (and that's a long time)

Yeah, I've been around a while myself.  Looks like I just passed my 11th
anniversary in this group.  :)

Oh, and BTW, I was doing the stage lighting thing nearly 30 years ago, and
we didn't have any PWM equipment, much less computer control.  The light
board in the booth was simply a remote control for large mechanical
dimmers (motor-driven rotary variable resistors) in the 'cage'.  A scene
change made all kinds of impressive whirring and buzzing noises, and the
heat coming from that equipment would power a small town.  I find PWM
incredible, especially since the introduction of low loss and high-power
MOSFETS.  I almost cannot believe the way we set any light level on a
2000w fresnel, with comparatively no heat generation and noise.

sdb

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