RE: Re: DIY Lighting DMX Option

[Keith Doxey <ukha@xxxxxxx>]

Quoting Ian Lowe <ian@wintermute-ltd.com>:

> You know, I was hoping discussion would come to DMX512 for the home...

It has been mentioned before several times. Someone was also using Midi for
lighting control using the Midi enabled dimmer packs from NJD hooked up to
the
GamePort on a soundcard. ( that was about 4 or 5 years ago I think!)

> DMX on the other hand... a totally open protocol, so bodgers like
myself can
> have a play with cool little PIC toys, and there are dozens (if not
hundreds)
> of manufacturers building the stuff, and much, much easier to get your
hands
> on without being a bona-fide installer.
>

Exactly. eBay quite often has used dimmer packs as well. Also because
DMX512 is
primarily intended for use in the entertainment and leisure industry, many
of
the dimmer packs are 19" rack mount.

> Watching this with interest -

What we need is an X10/xPL/xAP to DMX512 Gateway.

There is one caveat for DMX512 which some manufacturers have overcome.
Because
DMX512 is designed for speed there is no address information contained
within
the data packet.

It is a simple string containing Level1,Level2,Level3..Leveln. A break
between
transmissions is used to indicate the start of the next packet. A DMX
device
counts the incoming bytes until it gets to the ones it is listening for
then
goes to sleep until the start of the next packet.

It doesnt have to send all channels if you only have a 36 channel desk
thereby
being able to send data more often than a desk with 108 channels.

The caveat is that some equipment relies on receiving constant streams of
data
and the lights go out if the data goes AWOL. As I said, newer equipment is
designed for this eventuallity and will freeze at the last received level.

The price of the DMX dimmer pack quoted by David put it below the cost of
Lamp
Modules, Din Modules and X10 WallSwitches

Because of the response speed of DMX512 it meant that if you are using
coloured
lighting to create ambient scenes for your normal lighting you can have
some
really cool parties, just hook a DMX Lighting controller into the chain and
you
can turn the lounge into a disco :-)

Keith

www.diyha.co.uk
www.kat5.tv

UK Home Automation Meet 2004 - BOOK NOW!
http://www.ukha2004.com

http://www.automatedhome.co.uk
Post message: ukha_d@yahoogroups.com
Subscribe:  ukha_d-subscribe@yahoogroups.com
Unsubscribe:  ukha_d-unsubscribe@yahoogroups.com
List owner:  ukha_d-owner@yahoogroups.com