La Maitre effects

[Luis]

I am trying to design a controller for stage pyrotechnics and I would appreaciate it if anyone could tell me what are the technical specifications of the effects. In case there isnt an industry standard I am specially interested in the Le Maitre effects as they appear to be the more readily available.

 

What I mean is what is the current/voltage required to set them off, or the energy required to trigger them, or something along those lines. Or if anyone has any more specific knowledge of what requirements such devices need, I would be very thankful for any help.

[Ben Langfeld]

Unless you're an electrical engineer with quite a lot of knowledge of the subject, I would strongly advise just buying a commercial controller. If you ever had an accident when using your home brew controller, you'd be almost guaranteed some sort of court action and you'd be rather unlikely to win.

[Ynot]

Unless you're an electrical engineer with quite a lot of knowledge of the subject, I would strongly advise just buying a commercial controller. If you ever had an accident when using your home brew controller, you'd be almost guaranteed some sort of court action and you'd be rather unlikely to win.

I'd second that. Pyro controllers need to have safety mechanisms built in, both mechanical and electrical, and to build one that will conform to safe practices isn't easy.

 

Either buy a Le Maitre firer, or rent one when you need it.

[dbuckley]

Hmmm.... helpful answers.

 

You will find the answers you seek if you search the blue room, this has been discussed previously a number of times. The electrical engineering required is trivial, it's making sure the safety side is taken care of that is where the importance lies.

 

Does the current ABTT pyro guide have instructions on building a controller? It certainly used to. It also outlines the kinds of safety mechanisms that ought to be employed.

[scjb]

Yes, the ABTT guide does give guidelines to contruction, but the "current" edition is somewhat out-of-date. In my opinion, building controllers is a poor idea for a host of reasons... not least of which is the potential impact on your insurance cover. I seem to remember Le Maitre (amongst others) specifically mentioning in the literature that their product should be fired by either their own controllers or others on their approved list...

[p.k.roberts]

Unless you're an electrical engineer with quite a lot of knowledge of the subject, I would strongly advise just buying a commercial controller. If you ever had an accident when using your home brew controller, you'd be almost guaranteed some sort of court action and you'd be rather unlikely to win.

 

Whilst there are some very good reasons for choosing a commercial product, this kind of ill informed generic scare mongering is really most unhelpful.

[Luis]

Thanks a lot for your answers, I will look into the ABTT Guide. Don't worry I am not doing it to be used in a theatre straight away. I am just designing it and it will go through a lot of tests before it might get used in a theatre. At the moment I am just trying to get some initial idea of what it would entail to start from there.

 

Thank you again for your help.

 

PS. I am also an electrical engineer so Im not starting from zero, all is safe for now.

[scjb]

Whilst there are some very good reasons for choosing a commercial product, this kind of ill informed generic scare mongering is really most unhelpful

 

I disagree. If the worst did happen your insurance company is going to look very unfavourably on your (non-independently-tested) homemade controller and your supplier is not going to be liable under their Product Liability Insurance because you failed to use the product as required in the instructions (because you used a non-approved controller).

 

That's not scare-mongering... that's life.

 

EDIT - added quote

[Ben Langfeld]

Unless you're an electrical engineer with quite a lot of knowledge of the subject, I would strongly advise just buying a commercial controller. If you ever had an accident when using your home brew controller, you'd be almost guaranteed some sort of court action and you'd be rather unlikely to win.

 

Whilst there are some very good reasons for choosing a commercial product, this kind of ill informed generic scare mongering is really most unhelpful.

 

This has been gone over many times on the BlueRoom. The facts have all been laid down before, and it remains that using a non-independently tested, approved product is something that would end you up with a lot of questions being asked should you need to make an insurance claim or end up in court. It's not scare mongering, it's staying on the safe side and covering your arse in case things did go wrong. Ok, it may be slightly generic, but I fail to see how you can be any more specific given the information in the OP and the OPs profile. It may be that the OP is entirely competent to undertake such a project, but failing to point out the major possible risk would be a trifle negligent.

 

Additionally, I'd appreciate it if you could explain to me how such an observation is ill informed.

[p.k.roberts]

"Whilst there are some very good reasons for choosing a commercial product, this kind of ill informed generic scare mongering is really most unhelpful"

 

I disagree. If the worst did happen your insurance company is going to look very unfavourably on your (non-independently-tested) homemade controller and your supplier is not going to be liable under their Product Liability Insurance because you failed to use the product as required in the instructions (because you used a non-approved controller).

 

That's not scare-mongering... that's life.

 

EDIT - added quote

 

Actually, I think we probably agree; which might be one of the "very good reasons for choosing a commercial product".

 

My gripe with the post I criticised was more to do with comments like "Unless you're an electrical engineer with quite a lot of knowledge of the subject ....." I certainly don't think that being an electrical engineer would necessarily be an appropriate qualification to design this type of device, which makes me wonder whether the poster was qualified to make this comment. Using phrases like "home brew controller" is really just patronising and to say "you'd be almost guaranteed some sort of court action and you'd be rather unlikely to win." is simply supposition based on what? - do we have any case law on this one? Whilst I agree that our society is becoming generally more litigious, is far from being as bad as some of our more 'sensationalist' news papers would have us believe.

 

 

As Dbuckley said "The electrical engineering required is trivial, it's making sure the safety side is taken care of that is where the importance lies." If we are not careful we will get so scared that we will never do anything! Ultimately, if an accident occurred due to to incompetence/inexpertise then yes, your outlook would look very bleak. If however, you are confident that you have the competence to undertake the required task and could, if required, stand up and prove it (or have the wherewithal to employ an expert to do so) you might choose to take a different view. Of course such an expert witness might be prohibitively expensive which might be one of the "very good reasons for choosing a commercial product", which is where we started .....

[paulears]

There seems to be a kind of litigation panic here. Don't do this as you might get taken to court? Well - that is a fact of life nowadays, if you are negligent and the court decide you are not competent.

 

The secret is to do things that are within your capabilities. So, the question is all to do with applying a few volts to an approved device to make a puff of smoke or nice sparkly effect!

 

When you do this, using a device constructed by yourself, that meets certain safety standards, there isn't a problem. The only dangerous aspect to all this is the devices on the other end. The only real issue to think about is if your own desgn can ensure the outputs are isolated, and can't be set off by accident. This extends to critical things like capacitors - there was, I seem to remember one commercial controller that could still fire off a pod even when unplugged. So, the manufacturers don't always get it right, first time. I guess you could pay to have an independent test house check your one-off, but I can't see anything that makes this essential.

 

I can imagine a serious self-built project, built for safety with all sorts of one-off safety features. How about a fail safe output shorting system, making sure that there is no chance of setting off a pod when activated. Something like a failsafe that engages when mains power has been interupted, preventing a pod being set off if power is applied while an object has fell on the fire button?

 

I can envisage all sorts of really useful features, if the builder set their mind to it. None of these would cause any problems if it was done within the confines of their experience, skill and competence.

 

During the show I've just finished, using a commercial controller, the stage LX op, who was the 'keyholder', selected the wrong circuit and on cue, fired it! Two waterfalls upstage, rather than the two gerbs downstage went off - making a few people jump, but thankfully not causing any problems. Anybody who could design a device that could ensure this couldn't happen would be a good guy in my book. So maybe a programmable control that remembered the correct sequence and stopped out of sequence mistakes would be a sensible project - I don't know. I can't imagine commercial controls having this kind of feature unless very, very expensive - but a great project!

 

If any of us take short-cuts, take risks, do work outside of our comfort zone, then we may well end up in court - probably rightly so. We should not, in my opinion, stop innovation.

 

When I was 17 (not 18) I built a home made pyro control, using MAINS voltage, hard wired 2 core cable to lumps of 2x2 timber with a hammer beaten dent, with two nails around which I wound a thin strand of fuse wire. 1 teaspoon full of magnesium powder and I had great big flashes. I didn't know any better, nor did anyone else, and I had no supervision at all! The thought of what I did scares the hell out of me now - totally crazy, but I didn't know better. I guess if I had been 18, and an accident had happened, I would have deserved whatever punishment they gave me. Nowadays everything is so much safer - but it has to be a considered risk. Should we experiment and make our own pyros? Nope, never. How about make custom pyro pods? If they follow the design requirements of the manufacturers versions, then I can't really see a problem. Cable systems? Connectors? Lots of questions - but does this mean we can't customise? Depends on how we do it.

[Ben Langfeld]

There seems to be a kind of litigation panic here. Don't do this as you might get taken to court? Well - that is a fact of life nowadays, if you are negligent and the court decide you are not competent.

 

The secret is to do things that are within your capabilities. So, the question is all to do with applying a few volts to an approved device to make a puff of smoke or nice sparkly effect!

 

That's the point I was trying (possibly not very well) to make. I wasn't trying to say that no-one should ever do anything that could possibly be dangerous. I was meaning that when safety and your livelihood are involved, you should stick where you are comfortable. If designing nuclear reactors is within your comfort zone then great! But knowing a little bit about particle physics doesn't guarantee you that. (Excuse the utterly awful analogy!) Hope that clears things up a bit.

[Ike]

I am trying to design a controller for stage pyrotechnics and I would appreaciate it if anyone could tell me what are the technical specifications of the effects...

 

The firing currents around half an amp. Most systems use a resistor and LED to show there is continuity on its output(s) when armed typically passing around 10mA. The resistance of the igniters is very small (<2 ohms if I remember correctly), this can often be less than the wire feeding them! If multiple units are being used it's best to put the cartridges in series and use a higher voltage so as to reduce the effects of cable losses.

 

Safety measure wise ensure any channel(s) can be independently isolated and that nothing can fire without the key present and the fire button being pressed. Recessed buttons are the best so as to avoid accidental pressing and the unit should be solidly constructed so as to prevent anything firing if it gets coffee spilt on it or knocked off the table etc. These are just the basics, obviously there are a lot of additions that could be made.

 

If your making your own pods be very careful to make sure they are solidly constructed and have a way of being fixed down, also be aware that a lot of pyros throw out hot oxidisers during use. Le maitre have just changed their confetti cartridge supplier and the new ones now require an extra support dib dob.

[kje-kev1459]

hi, I must admit I agree with, and disagree with whats been said on this topic. if you have a good reason and experience for building one then I would think its a good idea, after all most of the commercial controllers on the market today started out in a similar way I would think. but on the other hand if you just want a simple controller the the Lemaitre or sky hi units are perfectly adequate and reasonably prised to. Of course if you need something a little more advanced the I guess building you won is not such a bad idea, personally I have always built my own controller, and to be honest I have seldom seen a commercial unit being used by any pros at all. But what I think is most important is you really do have a good understanding of electrics/electronics and also the appreciation of the consequences of a malfunction.

 

 

hope what I have said makes sence, good luck

 

Ps: might post a pic of my latest firing board......

[paulears]

I am trying to design a controller for stage pyrotechnics and I would appreaciate it if anyone could tell me what are the technical specifications of the effects...

If multiple units are being used it's best to put the cartridges in series and use a higher voltage so as to reduce the effects of cable losses.

Excellent reason for designing a custom unit!

 

Pods in series also have the unpleasant feature of failing more often. One dodgy cartridge, one poor connection and a brilliant effect lost! So controllers with either multiple outputs, that have high current capacity, with bigger psus could be the key.

 

Maybe then a range of remote splitters, to allow for shorter runs to parallel wired pods? I'm also quite a fan of using mic cables for pyros - I realise many people have a problem with this one, but it is very handy, and does allow 2 circuits down one cable. Anything to get away from the nasty 4 pins that are a real pain to use with decent cable with better current carrying characteristics.

 

Incidentally - the idea of series running with higher voltages does of course require a custom controller, and with a lot of pods, we're getting back to the increased risk of higher firing voltages. A fired pod with exposed terminal that could be touched?