Thread: Using DMX for props/lights/sound/activation

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Hi all,

This year I bought a 2nd fog machine and I specifically bought the more expensive DMX remote. I got the American DJ Fog Storm 1200.

First off.. are there any 400 or 700watt fog machines that come with DMX? Man.. I want some cheaper fog machines to mix up with DMX to spit out a small burst of fog, say for a scare effect with some lights.. dang if I gotta buy $150+ fog machines and $50 remotes to get DMX use! For example, the American DJ DMX remote only works with their 1200 or 1700 models. Why not their 700 model? For crying out loud, I don't need 20,000cfm of fog for a scare effect, I just need a 1 to 3 second burst of a little fog to add to the effect. Using DMX to turn on a light or two, activate a sound and spit some fog would be awesome, but I can only afford to add one or two things a year, and this year was some lights/fog machine. Ugh!! Why can't all of us that love to spend hours..days even setting up for a few hour event for kids, be rich!!

Anyway, I am curious how to make best use of DMX. I bought the Enttec open USB/DMX adapter, I see there is some free software out there, would love to know for Windows or Linux which is best to basically run short "triggered" sequences (or scenes I think they are called)?

Also, how do you trigger a DMX scene from say a kid stepping on a trigger under a mat, or sound/motion activated devices? I've not looked yet, but I gotta guess there is some two-wire trigger to DMX device out there that can be used to then execute a DMX scene? Now, I know the Enttec USB/DMX I got is one way.. I probably should have bought the PRO model that has an IN on it too.. not sure though if that would be needed. But, I am guessing there is a way to get the DMX scene software to trigger a scene when it receives a message on a DMX input channel?

Or is there some trigger to USB interface that can be used that the DMX software can then use to trigger a scene?

Also, if I have multiple props set up with DMX stuff.. like a grave yard scene with fog/light/sound, and a separate flying ghoul with light/sound, can a single software trigger two (or more) scenes back to back almost instantly, and run in some sort of continuous "listen for trigger" loop? There would also need to be some sort of delay before the trigger could fire again.. so the prop could reset, and/or account for back to back foot traffic triggering too fast or often.. and of course those pesky kids that just sit there and stomp on the trigger over and over.

I have a couple computers, but they are big desktops. I also have a netbook, and a laptop that both could be used, although with only the one DMX interface, it would be ideal if I could some how handle all this from one computer.

Thank you.

Just have a few minutes here, but...

You can convert smoke machines to DMX control by hacking the existing controller, and adding a relay across the switch. The relay can be a) a dedicated DMX relay, b) controlled by an indandescent dimmer box, c) controlled by the Medusa DMX Do a search, several people have done this already.

For software, most here use Brookshire VSA (commercial), some use Vixen (free).

DMX is one directional, for the most part. There are some advanced DMX uses (RDM) that provide some kind of status data back to the host, but I don't think any of the animation packages use it.

So, trigger inputs aren't handled through DMX. But there are a couple sources for getting triggers into the animation software. DMXorcist and Helmsman are two USB input examples, each with their own software for running VSA routines. Each of these (I believe both) have time outs, and rules you can set up, for which input triggers what routine, and under what circumstances.

In answer to your last question, DMXorcist is also capable of interleaving multiple asynchronous routines to different scenes.

Hope this helps
- Hook

Thank you Hook, that was helpful. I looked up Medusa.. its $90 from what I saw.. does that only control a single prop? I am not quite clear on what it does? I got the Enttec USB open dongle, thought that is all I would need to control DMX equipment. I found a thread on here, and on google regarding using a simple 12v relay to trigger a manual fog switch, that is pretty cool. What I am not entirely sure of is how that then interfaces to a female DMX plug and how you set the channel to trigger the on/off switch? I am guessing you interface that relay setup to the medussa board and that handles the DMX configuration? If so, does the Medusa plug into USB on the computer, or does that then plug in to the Enttec adapter?

The Medusa could control multiple props but you would be losing out on some of the key features of DMX (like reducing wiring), and using DMXorcist you can address multiple simultaneous routines to a single board, or indeed to multiple boards.

The Medusa is a DMX device, like your fogger, and it plugs into your DMX chain (like your fogger), and the DMX chain plugs into the Enttec which plugs into your computers USB port

andjarnic,

We are the two Brian/Bryans Brother Grimm spoke of in your other post. Phoenix is right. Your computer plugs into your Enttec through USB, which enables your animation program to control a DMX network. That, in turn, connects to any and all of your DMX devices: smoke machines, strobes, Medusa, etc.

DMX is basically a big pool of channels numbers with values. Each channel number has a value that the animation software can control, and each device you hook up to a DMX network "listens" to one or more channel numbers. So, for example, on a moving light fixture, one channel would be for X rotation, another for Y rotation, another for color... etc. On the Medusa DMX board, 8 of the channels are dedicated to controlling 8 servos, 8 more are dedicated to controlling 8 LED dimmers, and the final 8 are dedicated to controlling the switch outputs. To answer your question, if the data on a "switch" channel is 0, the switch will be off. If it's >=1, it'll be on. So, the Medusa board is an interface between DMX, and other devices (servos, LEDs, relays).

What Phoenix says is true, about increasing the wiring. It would be simpler wiring to connect a DMX cable directly from your Enttec to a smoke machine. And from that smoke machine to the next, and so on. That's one benefit of DMX. However, it sounded like you wanted to get away from paying the "$150+ per smoke machine and $50 per controller" that's required to have direct DMX control of your foggers. Using a Medusa board would let you control multiple (cheaper) smoke machines, with a little hacking on your part (adding a relay to the controller that came with them).

The Medusa board isn't the cheapest way to control one relay using VSA. But that's not really what it's for. I designed it for controlling most of the scene - multiple servos, lighting, and multiple relays.

- Hook

Hook,

Excellent.. I understand now about Medusa. It sounds like it's not for me right now, as I am just starting out. I am thinking the DMXorcist might be the way to go, so that I can get some input triggering from step pads and motion detectors to trigger VSA sequences that then can fire some DMX channels to do lights, a fog burst and possibly some sort of solenoid. Like you said, I think using a relay on the smaller fog control would be the better way to go, at least for now. I am not sure I'll ever get big enough to have a huge scene of props running.

Thank you for the replies.

You'll still need a relay/dimmer pack to trigger the hacked fog machine switch with DMX. Something like this: Chauvet DMX Dimmer Pack

Then you can dim and control non-DMX lights, or switch things on and off, like relays.

Ah.. for some reason I thought there was a way to take a 3 pin DMX and attach it to the wires of the relay and it would work.. figuring that the DMX was just voltage across wires.. granted it wouldn't have the ability to handle different values of DMX on a channel.. but to just apply a voltage to a relay to do on/off switches I figured it may work like that. How do the wires off of the relay connect to DMX? I understand via the medusa board..but if using DMXorcist, do they connect to that too? I need to read up on DMXorcist more.

Holy crap..I just saw that its like $400 for DMXorcist? Suddenly the Medusa board looks much nicer! I thought it was cheaper for some reason. Man, I am going to have an impossible time selling the costs of haunting kids for a few hours once a year to my wife!

Just to add clarification...

Medusa DMX is an output-only device.
It takes DMX data, and controls devices based on what the data coming down the lines tells it to do.

DMXorcist is show control software, coupled with an input-only device.
The hardware component takes input triggers from mats, etc, and sends the data to the computer through USB. The software component will then start the proper routine.

So, they're really two completely different things. From the hardware perspective, one's for enabling your computer to control props, and the other is for getting external triggers into the computer (and playing the proper shows in response to the triggers). Phoenix, please correct me, if I'm missing anything on the DMXorcist.

In answer to your other question about hooking relays directly to DMX, think of DMX like USB or a serial cable. The voltage levels aren't meant to directly activate anything, they're just meant to convey information. A device is always needed on the other end, to decode the information, then control something in response to the information.

- Hook