RE: DIY dimming (not X10)

[Keith Doxey <keith.doxey@xxxxxxx>]

Analogue 0-10V is an old control standard used in stage lighting.

all modern stage lighting kit is DMX512 (Digital Multiplex)

Digital is the way to go because the triac only has 2 states....ON and OFF.

Digital control is easy to implement. You need to create a counter that
counts from 100-0 syncronised to the crossing of the mains cycle. Pass a
value between 0 and 100% for the light level you require. Compare the two
and when COUNTER => SetLevel then turn the triac on. One PIC chip can
easily
accomplish this.

My description is over simplified and doesnt take into account the non
linear characteristics of light output from different types of light.

John Tankard has built his own lighting system in the way described above
and I am sure he will add more to this thread.

Keith

> -----Original Message-----
> From: James Hoye [mailto:jhoye@xxxxxxx]
> Sent: 11 October 2000 11:39
> To: 'ukha_d@xxxxxxx'
> Subject: [ukha_d] DIY dimming (not X10)
>
>
> Found the following information:
> http://www.hut.fi/Misc/Electronics/circuits/dimmer4.html
>
> Don't know about the build cost - but the main components (4
> triacs) are
> around the 1 pound each mark I believe.
>
> Would appear to be _considerably_ cheaper than Lutron, and to keep the
> copper is king camp happy, possibly more reliable than X10.
> Of course, when
> you cabled, you added CAT5 everywhere just for eventualities
> such as this
> :-)
>
> This thing looks as though it's been design for rack mounting from the
> outset - and with the 0-10v control I'm sure someone (Keith
> nudge..nudge..wink..wink) could build an appropriate
> controller that could
> interface via serial and serial driven keypads to provide
> control.  I mean,
> now that the KAT5 units are a done deal, you'll need
> something else to keep
> you busy in January when you've finished the AV switcher for Xmas!!!
>
> :-)) James...
>
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