Oppinions please, pyro over DMX

[dave]

I have been thinking about doing this safely lately, just wanted some opinions.

My idea is to use quite a few DMX channels, so a particular value has to be hit on each of say 6 channels, and further channels are used for crc error checking.. Not sure, but I think if done this way, it will eliminate any risk..

Thoughts?

[Things]

That sounds like it would work, and spreading it over a few channels would definitely make it safer. One thing you may wanna consider is some kind of isolation from the DMX line on the pyro side. If you get some kind of spike it could be quite dangerous.

[Jem]

Hi Dave

You might want to post the same question here...

http://www.blue-room.org.uk/

There's an 'effects and pyro' link, that's probably the best place to ask. There's some pretty smart folk there who may be able to get you a definative answer.

Cheers

Jem

[soforene]

Le Maitre are a company that do a lot of effects in this area and I believe they have some DMX controllers (at least they did the last time I was poking about their web site).

Might be worth taking a gander at what they do......

[mixedgas]

Just so you know, the DMX standards handbook says NO.
If you'd run another cable pair as a interlock with a relay at the end, I'd feel better about it.

Steve

[dave321]

I have been thinking about doing this safely lately, just wanted some opinions.

My idea is to use quite a few DMX channels, so a particular value has to be hit on each of say 6 channels, and further channels are used for crc error checking.. Not sure, but I think if done this way, it will eliminate any risk..

Thoughts?

dave,

from what i have read on various uk pyro forums controlling pyro using dmx is a DEFINATE NO NO.
i do not claim to be a profesional pyrotechnician but my understanding is that, certainly from a stage / proximate us of pyro, dmx is just not considered robust enough and is not recomended.
it would be better to fire pyro with a proffesionally made controller.
i would check with a profesional pyrotechnician, especially if stage / proximate use is required.

just my 2 peneth

dave321

[colouredmirrorball]

They use MIDI to control the pyro effects now. (correct me if I'm wrong)
From my experience MIDI is far more sensitive to static electricity! I have had several issues with my fog machine and MIDI. Sometimes, when I press the fog button, my lights go in black-out, because the fog machine generates such a high electric shock (?) that my MIDI-controller gives the preset signal for black-out. You can even hear the shock through a box!

[heroic]

They use MIDI to control the pyro effects now. (correct me if I'm wrong)
From my experience MIDI is far more sensitive to static electricity! I have had several issues with my fog machine and MIDI. Sometimes, when I press the fog button, my lights go in black-out, because the fog machine generates such a high electric shock (?) that my MIDI-controller gives the preset signal for black-out. You can even hear the shock through a box!

MIDI is bidirectional, which means that a MIDI device can establish a positive communication with the controller. DMX512 is unidirectional, which obviously impedes this. That means that a MIDI pyro controller can, if suitably designed, make absolutely sure it's supposed to be firing the explosives; a DMX pyro controller couldn't do this, so it's not safe.

I've had problems with fog machines generating electromagnetic noise too. They went away when we got the Antari.

[dave]

MIDI is bidirectional, which means that a MIDI device can establish a positive communication with the controller. DMX512 is unidirectional, which obviously impedes this. That means that a MIDI pyro controller can, if suitably designed, make absolutely sure it's supposed to be firing the explosives; a DMX pyro controller couldn't do this, so it's not safe.

Actually, midi is only unidirectional, but most MIDI equipment has a midi in and a midi out, to allow bidirectional communication..

TBH, I can see what use MIDI would have in pyro. Cable length is limited to 5m IIRC, and that is bugger all. Even for music use its pretty outdated..

Also, newer RDM gear can communicate bidirectionally over a DMX network. Have just been trying to purchase/download the standard, but ANSI doesn't like my credit card

[heroic]

Actually, midi is only unidirectional, but most MIDI equipment has a midi in and a midi out, to allow bidirectional communication..

Midi's *designed* to work that way, rather, whereas building a duplex network out of DMX512 would be a serious abuse of the standard.

Personally, I'd probably use something like the Pyro Systems boxes. It's not worth blowing yourself up to save a few bucks.