15 replies to this topic

[volcano]

Hi guys im a new member from turkey!! im %100 turk
and i m a student in technichal universty and study abouth mechanichal engineering!!!this year i will finish my scholl at last if i pass one lesson that its thesis! !!
My thesis is ?production of pyrotechnic digital ignition system?! (i choised)The system I want to create will be a software program that I can adjust the time code, number and sequence and an ignition module that will start when i want it..
so my question is can i use lighting controllers which are micro-processor based instead of standart ignition programable systems?.. What do you suggest?
by the way i interest in technics of fire especialy fireworks...maybe i could do this job seriously after i finish my school!!
thanks..

[adamw]

Computer-controlled ignition systems are normally purpose-made - ie designed specially for the job and it is not common (or safe) practice to use a type of controller not designed for pyrotechnics. This is because a reliable safe/arm system, interference suppression, continuity test etc will be required.

[BurlHorse]

Hi guys im a new member from turkey!! im %100 turk  
and i m a student in technichal universty and study abouth mechanichal engineering!!!this year i will finish my scholl at last if i pass one lesson that its thesis! !!
My thesis is ?production of pyrotechnic digital ignition system?! (i choised)The system I want to create will be a software program that I can adjust the time code, number and sequence and an ignition module that will start when i want it..
so my question is can i use lighting controllers which are  micro-processor based instead of standart ignition programable systems?..  What do you suggest?
by the way i interest in technics of fire especialy fireworks...maybe i could do this job seriously after i finish my school!!
thanks..

 

Welcome Volcano, Get in touch with John Sagaria, www.sagaria.com or John@Sagaria.com He is The Man To Talk to......Tell Him "Bear" Told You to Contact Him, He Is The Designer of the "Fire One" System, and a Member of The Crackerjacks over here in the US, You guys might be able to further each others causes!

Regards,

Bear

[volcano]

Nice to join here thanks Burlhorse!!
thanks to interested to me ''bear''.i ll tell my ideas to him..''by theway i downloaded to fireone's demo software many ages ago!name is scriptmaker 2000!!i needed a keykode to activate it!!because they tell us,send an email to get keykode.then i sent to them,i stiil wait to receive its keykode''!!i mean that company just interests the money!!
sorry if i sound bad..

[volcano]

adamw!you are definitely right! The most important feature, which is something that many people overlook when designing their own systems, is that there has to be a way to stop the musihal firing show in the event of an accident!!Another important feature is the ability to test the connections from the firing modules to their e-matches.you will also need to provide a means to remove the charge from the circuits to put them back into a safe mode.
Finally, it is best to have a firing module which will shunt (i.e. short-out) the e-matches for safety during display setup. The shunt is removed when the display setup is complete. On some systems the two modes are called "shunted" and "armed".
so i mean if i say i find a software with its hardware (synchronize their lights to music and view new designs in motion prior to actually building the display shows)that include to all that functions!!!can i use it instead of specific firework digital ignition systems!!

[adamw]

Yes, you can. But that hardware will probably be a firing system!! Only things designed like that are meant for firing fireworks!!

[electronicsuk]

Sorry to dig up an old topic, but this is my first post here and this seemed like a relevant thread to use rather than starting anew. At some point (read: when time permits) I'm looking at constructing a microprocessor controlled firing system. The basic idea is that power and control signals (RS485) get transmitted down a 3-core cable to as many firing modules are required in a daisy-chain fashion. The RS485 connection is obviously bi-directional so I can get feedback to the firing panel on the status of the e-matches and the firing modules themselves.

I'm pretty confident I can get my head round most of the project, but I do have a question for those with some background in electronics. I will be designing the modules to use capacitive discharge firing, however, each module will have at least 8 output channels. I'm not too keen on having to include an individual HV generator circuit and capacitor for each channel. Can you think of any downsides to charging one large cap and using this as the firing source for all 8 channels? The only downsides that come to mind on first thought are whether or not this would give enough 'oomph' if all 8 channels were ever to be fired consecutively on one cue, and in addition, if an accidental direct short occurred across one of the channels the cap would instantly discharge upon firing, quite possibly not giving enough time to recharge if there were another cue on the same module too soon after.

The other option is to have one HV generator feeding an individual capacitor for each channel, probably through a diode to provide isolation between channels. Views, comments, ideas and criticism on the above ideas much appreciated. Also, if I can devote enough time to this project then I would like to add some extra features, perhaps even computer control instead of a dedicated firing panel. In an ideal world, what features would you include on a 'dream control system'?

Cheers,

Matthew

Edited by electronicsuk, 14 November 2005 - 09:08 PM.

[adamw]

The main thing to focus on is the recharge time, as a lot of times there will be the need to fire one after the other in fast succession.

[RegimentalPyro]

Firelite / FireOne modules use one big cap, with enough oomph to blow 32 ignitors at once. It's charged during a 5 sec startup cycle. I don't know what system [if any] is in place to present a short taking all your charge....

[Andrew]

Firelite / FireOne modules use one big cap, with enough oomph to blow 32 ignitors at once. It's charged during a 5 sec startup cycle. I don't know what system [if any] is in place to present a short taking all your charge....

It depends; each ignitor will require a critical amount of energy to be dissipated in it before it will blow. With all this added up, and losses accounted for, the one capacitor idea means a v.large and expensive capacitor. A cheaper and easier way to achieve the same effect is to have an array of smaller inexpensive capacitors.

Using HV generators is slow unless they are big and thus expensive. By reducing the step up in voltage, you reduce the effective internal resistance of the source, leading to smaller charge times. As a guide stepping up by a factor of 4 is a limit for fast charging if you do not want a large and relatively expensive circuit

[karlfoxman]

It depends; each ignitor will require a critical amount of energy to be dissipated in it before it will blow. With all this added up, and losses accounted for, the one capacitor idea means a v.large and expensive capacitor. A cheaper and easier way to achieve the same effect is to have an array of smaller inexpensive capacitors.

Using HV generators is slow unless they are big and thus expensive. By reducing the step up in voltage, you reduce the effective internal resistance of the source, leading to smaller charge times. As a guide stepping up by a factor of 4 is a limit for fast charging if you do not want a large and relatively expensive circuit

If anyone is interested in some 10,000uf 80v caps give me a shout, i have 8 of them. Say ?4 each inc p&p in uk. Was going to be used in a 3kw amplifier, i may have another 8 if i remove them from the psu i made.

Edited by karlfoxman, 15 November 2005 - 10:28 AM.

[electronicsuk]

Using HV generators is slow unless they are big and thus expensive. By reducing the step up in voltage, you reduce the effective internal resistance of the source, leading to smaller charge times. As a guide stepping up by a factor of 4 is a limit for fast charging if you do not want a large and relatively expensive circuit

I suppose rather than HV generator I really should have said boost converter, the plan is to run something like 24v for supply and step up to in the region of 100v or so, possibly less. So you think the option of using a capacitor per channel is best, with diodes to keep each capacitor isolated and a single boost converter to get the charging voltage?

[Andrew]

Having a capcitor for each que is a good way round the charging time; you would only need to charge it all once, and each firing does not affect the next. But that's a lot of capcitors, if you want more than 8 ques.

In this case, the boost converter does not need to be that large, you could charge the entire system over 10 seconds or so.

What method are you going to use for Isolation/switching?

[electronicsuk]

What method are you going to use for Isolation/switching?

At the moment I'm leaning towards a power MOSFET for each channel. They aren't particularly expensive these days and many of the HEXFETs manufactured by IR provide a very high power rating in a small package. I think they should be rugged enough for the application, otherwise the other option would be power transistor or relay switching. Relays would probably provide the most rugged solution, they aren't affedted by static, interference or any of the other problems associated with semiconductors, but at the expense of extra cost and physical space.

[Andrew]

At the moment I'm leaning towards a power MOSFET for each channel. They aren't particularly expensive these days and many of the HEXFETs manufactured by IR provide a very high power rating in a small package. I think they should be rugged enough for the application, otherwise the other option would be power transistor or relay switching. Relays would probably provide the most rugged solution, they aren't affedted by static, interference or any of the other problems associated with semiconductors, but at the expense of extra cost and physical space.

You can get N and P channel enhancement MOSFETs for about 19p each, they are expensive if you compare them the resistors, but not if you compare them to ICs. As long as you use a strong enough pull down (pull up for P channel), that is probably <100kΩ, static and noise will not be a problem at all. The TO-220 package (what most medium power MOSFET come in) can dissipate 125W before you need to think about anything other than a normal heat sink; they are very robust. Also as you would be switching, and not matched driving, the transistor would only dissipate 10W or so during the ?ON? stage.
You could use a pair of MOSFETs for each channel, an N-channel on the low, and a P-channel on the high side. This would provide complete isolation from the internal potential, so no nasty shocks, either electric or devices going up unexpectedly!!!