Comments on: DMX light control for home automation

By: Insteon vs X10

Insteon vs X10 — Tue, 24 Nov 2009 19:08:27 +0000

It may be robust, but when you consider the cost and complexity of getting this going versus a second generation system like Insteon or Z-wave, this doesn’t seem so hot.

By: Kaijuu

Kaijuu — Sun, 10 Feb 2008 23:35:48 +0000

Nice setup. A pity you can only use regular incandescent light bulbs with systems like these; not very energy-efficient.
I thought of building something similar, but went for a remote with a bunch of relays instead, as all of my lighting is either LED’s or Energy-efficient.

By: MRE

MRE — Fri, 08 Feb 2008 05:54:18 +0000

DIY DMX in the interweb begins and ends with http://www.dmx512-online.com/

I used to be a long time lurker there.. even built the ISA dmx interface card (no longer on the site?) a long time back.

By: Brian

Brian — Thu, 07 Feb 2008 18:21:09 +0000

I personally prefer Vantage lighting control systems (vantagecontrol.com). Super easy to install, set up, etc.

By: LoopyMind

LoopyMind — Thu, 07 Feb 2008 16:00:52 +0000

So I take it he’s not using Energy saving light bulbs… seeing those are a pain/impossible to dim…

By: RidoKilos

RidoKilos — Thu, 07 Feb 2008 04:27:51 +0000

I work with stage lighting and it’s pretty safe to say that all of that is completely unnecessary to ever have DMX in a home. I want it.

By: Alfie

Alfie — Thu, 07 Feb 2008 04:00:00 +0000

Interesting project.
I'm curious about how you interfaced your home wiring into the system Dan. Is it through receptacles and cords? Or through a bunch of J-Boxes?
The single light sensor seems a touch inadequate, if you have a basement it is probably always darker than your upstairs and if programmed in the same line as the upstairs might then not come on when you needed it too.
As far as knobs go- try this as a starting point-
http://www.hdsupplysolutions.com/webapp/wcs/stores/servlet/ProductDetailsDisplayView?langId=-1&storeId=10051&catalogId=10051&rstate=336413-1&req=catalog
As an electrician I find rotory knobs distasteful- I would rather see slide fader.

By: dan c

dan c — Wed, 06 Feb 2008 20:16:47 +0000

Does anyone have a DIY computer->DMX (not necessarily RS-232) that they can recommend?

By: stefan

stefan — Wed, 06 Feb 2008 19:30:55 +0000

@11: dirk, all you need is 2 par cans face to face.

By: Dirk

Dirk — Wed, 06 Feb 2008 17:11:38 +0000

I'm a theatrical lighting designer, and working on ohio this summer we decided we wanted a DMX toaster.

so, someone get on that.

By: William Munns

William Munns — Wed, 06 Feb 2008 11:40:50 +0000

DMX is dead easy to read with a PIC, the signal is a standard UART form but sent over balanced line RS422/485. The form of the signal is – Line held low (break) which will read as an overrun, then the line idles (high) and then the data comes as a byte stream with the channels identified by their order (start counting at zero).

a very simple protocol which simply repeats, so no need for error checking as the data is corrected on the next pass

By: Dan McGrath

Dan McGrath — Wed, 06 Feb 2008 10:53:23 +0000

Thanks for the comments guys!

The dimmers I used aren't as expensive as you would think, about Â£50 each - and for that you get 4 channels! A normal dimmer here is about Â£7 (for 1 channel) so the extra cost isn't that great.

I intend to post more HA stuff, as the rest of my house is automated too, the heating (all that plumbing you can see) is probably the most impressive (I think)

Anyway, glad you enjoyed it, and thanks for the positive comments.

-Dan

By: adam

adam — Wed, 06 Feb 2008 09:27:41 +0000

he could put a rotary encoder at the light ‘switch’ and have it tell the server to turn a light up/down. it might also be a good idea to put a backlit push button. When you move the encoder the software detects it and puts the light in manual mode. When the light is in manual mode the server tuns the push button’s backlight on. To switch the light back to auto you push the button and the backlight tuns off.

This would let you have a software ‘admin’ app which could toggle the manual/auto state. Which would be handy if you left a light in manual mode and don’t want to get up to change it. :p

By: atrain

atrain — Wed, 06 Feb 2008 07:43:58 +0000

ok. 3 wires from board, 3 wires to pot (for watching if someone is playing with it), 2 wires control relay that swaps between digital pot + normal pot. thats 8 wires, perfect for CAT5 cables. A 4ch dmx dimmer is $125. Go to Analog Devices, digital pots are 50c -> $1, ADC's can be had for $5 (for determining if pots being used). Household dimmers are $15. $60 + $20 + 4 relays = $100ish, and now don't have to send power back from wherever the relay is located.

I'm biased towards my schematic cause this seems to be a great project to do, and I already have dimmers and relays and don't want to go out and buy a new set wrapped in a pretty metal box.

BTW: Can't access / on his server! Is this the only page he has? I want to see how he detects when you enter/exit a room, that sounds like fun!

By: MRE

MRE — Wed, 06 Feb 2008 07:31:42 +0000

also, a digital pot would give the server a way to *read* the pot value on the dimmer, but not a way to *affect* the value on the dimmer without a complete overhaul of the dimmer unit and a bidirectional communication line.
digipots come in multiple formats and price ranges (as well as levels of intelligence, communication format, etc). a digipot that models a mechanical pot (with endstops for Off and full on) would need the ability to turn itself based on the data from the server thus representing in the real world the value given. These are quite expensive. Especially when talking about fitting the whole house with them.