Re: Using DMX to control the iColor LED lights

["Chris Deighton" <Chris@xxxxxxxxxxxxxxxxxxx>]

Hi Stephen,

> as they accept standard DMX512 I can't forsee any problems

Just a word of warning... The iColor Cove units are capable of
receiving a DMX signal, but not without a converter. Standard DMX is
RS485, whereas the iColor units need to receive a single, unbalanced
24V data signal. The timing and format (break, mark, start code, data
bytes, etc) of the two signals are identical, but the voltages and
transmission method (balanced vs. unbalanced) are different.

Color Kinetics sell a special power supply that solves this problem by
having a DMX input on it, and the appropriate circuitry to convert the
data signal to the required level. Alternatively, if you already have
a 24V power supply and you feel that way inclined, it'd be possible to
build your own circuit that converts from RS485 to an unbalanced 24V
signal.

Assuming you do have a converter from DMX to the Color Kinetics 24V
signal, you'll then need to choose a suitable DMX controller.

The DMX data stream is basically 512 8-bit values that get sent
repeatedly down the wire at a rate of up to 44Hz. It was originally
designed for controlling dimmers, so a single DMX connection can
control 512 individual dimmers - one DMX channel per dimmer. However,
DMX is now also used to control other forms of lighting, where a
single light may use any number of control channels. In this case, the
iColor Cove units each use three channels (one each for R, G and B).
Therefore you'll need a controller that can control at least 3 x n
channels (where n is the number of iColor units you have).

If you're interested, there's some basic information on DMX here:
http://www.euro-pa.be/dmx.html

So, ideally you'd use a controller that directly supports controlling
RGB LED fixtures, as this will allow you to program them in terms of
RGB colours. The better controllers will also allow you to create
effects (such as travelling rainbows, color chases, etc.)
Alternatively, you could use a controller that simply allows you to
manually manipulate each channel of DMX data. In this case, channels
1-3 will control the first unit (R, G and B respectively), channels
4-6 will control the second unit, etc.

Of the controllers you linked to on CPC, the first one will be
unsuitable as it's only designed for controlling a specific type of
light (not RGB LEDs). The second one (the DMX-60) looks like it's a PC
based controller that can transmit up 60 channels. If this is the
case, you should be able to run up to 20 iColor coves from it. (I've
not looked at the PC software though, so you'd best check that first
to see what it can do.)

The Cinetix and Milford products should also be capable of achieving
the required results, although I've not looked at them in detail.

If you're interested, the company I work for (www.pharoscontrols.com)
produces a product called the LPC, which is a DMX controller designed
specifically to control RGB led lighting in an architectural setting.
We also provide free 'Pharos Designer' software which is used to
design the show and download it onto the LPC. It's probably way more
than you need in this case, but it might give you some ideas as to
what's possible!

I hope some of this is useful... and good luck with getting your
iColor Coves working!

Cheers,

Chris.