Capacitor Discharge Project Fireworks

[mybuickskill6979]

i'm planning to make a nice little 6X6 rack. and firing system but i want the cues to be low power to a box to control the highpower stuffs. but that won't be till i learn a little more.

 

[Sam Jelfs]

thats basically what i am doing, one box with buttons to arm each channel, plus fire button, control sent over bell-wire to the pyro / firework location, where there is a second box, which has all the switching for actual detonation. I'm also incorporating so when you arm a channel, that channel is tested to make sure you have continuity through it, before the "armed" indicator led lights up on the control surface.

well that's the hope. Depending on what protocol you use to send data between the units, thats the hard part.

 

[wakanga]

thanks sam..

why not try using RS-232 interface to send the data to the receiver and decode it and after decoding it sending it to the corresponding channels to fire the fireworks

Computer -->RS-232 interface-->Decoder-->Receiver-->Fireworks

im not a pro and i don't know much about controllers...i'll just fill in some ideas that might help...good luck with your project...im excited to see it's results

 

[hfireworks]

This may give you an idea of what I am doing, if it will help you out.

 

[Sam Jelfs]

wakanga - that was along my original ideas, to interface my system into a show control system, running software such as jtype or medialon to control it. Unfortunately, chatted to my project tutor, and we decided i just didn't have the time, given that I haven't finalised my design yet and I have to have it submitted in a month, I think he was right! So I am focusing on getting good data transfer between the control surface and the receiver, with the hope that in the future I can develop it further into an integrated system.

hfireworks - Nice bit of kit you've got there, a lil more compex than mine will be :lol: does yours interface with a computer to control the fireworks, or is it a matter of physically arming the channels you want to fire, and hitting fire?

 

[cadstarsucks]

wakanga - that was along my original ideas, to interface my system into a show control system, running software such as jtype or medialon to control it. Unfortunately, chatted to my project tutor, and we decided i just didn't have the time, given that I haven't finalised my design yet and I have to have it submitted in a month, I think he was right! So I am focusing on getting good data transfer between the control surface and the receiver, with the hope that in the future I can develop it further into an integrated system.

hfireworks - Nice bit of kit you've got there, a lil more compex than mine will be :lol: does yours interface with a computer to control the fireworks, or is it a matter of physically arming the channels you want to fire, and hitting fire?

I was thinking... the easy way to do it would be a small remote micro and, say a car battery, using a RS422 comm link ( the long distance cousin of RS232 ) to any PC. A simple set of ASCII commands and any terminal program could control it.

Then you would be able to sequence as well as trigger them and there would be no big IR drops to contend with.

Even simpler would be simple shift registers and a bit stream and a clock as far as programming is concerned.

I hope this helps, I only touched the surface of the thread so am not sure what has been suggested already.

D.

 

[Sam Jelfs]

rs / eia-422 doesn't specify the data structure does it?
the key thing here is safety, and i would still have to implement some form of protocol to manage the data and error checking. I think more so in stage pyrotechnics, which is my background, a misfire or fire of the wrong channel could be lethal if the "talent" was in the way...
a misfire in fireworks may look shite, but, shouldn't pose such a high risk as there shouldn't be anyone near them (hfireworks - that right? using a remote system there shouldn't be anyone near the actual devices?)

 

[cadstarsucks]

rs / eia-422 doesn't specify the data structure does it?
the key thing here is safety, and i would still have to implement some form of protocol to manage the data and error checking. I think more so in stage pyrotechnics, which is my background, a misfire or fire of the wrong channel could be lethal if the "talent" was in the way...
a misfire in fireworks may look shite, but, shouldn't pose such a high risk as there shouldn't be anyone near them (hfireworks - that right? using a remote system there shouldn't be anyone near the actual devices?)

True, they really only define signaling levels, connectors and pin numbers. The UARTs do have parity built in that can be checked and rejected if there is a mismatch.

It is actually easy to implement a simple command/response system that at minimum checks the byte parity and responds if the command is accepted and recognized. The controller can the resend if needed. If commands get more complicated you can add a block check as well.

D.

 

[zotdoc]

Just a quick question and idea. What would be wrong with using 120 volt ac current for this purpose. I am working on a system to synchronize fireworks to music. I was wondering if you could use logic level inputs to contol an optoisolated triac that would fire the ematch or home made nichrome ignitors by turning on a 120 volt ac source. Of course, if you had to run 600 feet of extension cord to your slats you would have a big voltage drop, but you would still probably have 80 or 90 volts ac which should be plenty of juice to melt a few nichrome wires. I'd appreciate anyone's thoughts about this. Thanks.

 

[Sceadwian]

You're going to need to make sure your poweer source is properly issolated and current limited to prevent accidentaly shorts in the wire from zapping people badly or starting fires, but it's doable.

 

[cadstarsucks]

You're going to need to make sure your poweer source is properly issolated and current limited to prevent accidentaly shorts in the wire from zapping people badly or starting fires, but it's doable.

I do not think the powers that be will let you do that. I still think the remote car battery would be better.... you could rig an RF link through a pair of inexpensive walkie-talkies.

 

[Nigel Goodwin]

I do not think the powers that be will let you do that. I still think the remote car battery would be better.... you could rig an RF link through a pair of inexpensive walkie-talkies.

I agree, keep it safe - not a good idea to use mains when you don't need to, and a car battery has got plenty of power!.

However, I would disagree with walkie talkies, it would also presumably be illegal to use them for data transmissions? (licence free for voice only), use a pair of licence free radio data modules.

 

[Sam Jelfs]

i would agree, not to use mains voltage, be it 240 or 120, safety is a key element here. Though saying that, you have to remember that a car battery can easily give out 100amps or more over a short space of time.

as for the RF link and cheap walkie-talkies, thing you would have an issue of cross-talk and the fact that anyone near by, say the stewards at the firework show, could tune into the same frequency, and you have this wonderful stream of data that is out of your control.

cadstartsucks - very true, could use parity bits, but I am then reliant on my coding skills more and more, which is a bad idea, I'm a sound engineer / acoustician normally!
the idea behind my system is to use a proprietary protocol, meaning that when a "client" asks how i guarantee safety in the data stream I can turn around and say, "well, its the same system used to in the brakes of your car", generally makes people feel a bit more comfortable about it. (not forgetting that in fact this is all a load of rubbish, as the system will never be developed further than I need it to be, which is just far enough to get me an A grade for my dissertation, :lol: )

 

[Sceadwian]

Why not CadStar? All you need is an issolation transformer with a low VA rateing.

 

[Hero999]

However, I would disagree with walkie talkies, it would also presumably be illegal to use them for data transmissions? (licence free for voice only), use a pair of licence free radio data modules.

Well I don't know but the sort I used to have worked on 27MHz and had a morse code button - I suppose that's data transmission.

 

[cadstarsucks]

I agree, keep it safe - not a good idea to use mains when you don't need to, and a car battery has got plenty of power!.

However, I would disagree with walkie talkies, it would also presumably be illegal to use them for data transmissions? (licence free for voice only), use a pair of licence free radio data modules.

Got me... I was thinking that the band was set aside for voice band communication... using frequency shift keying you can stay in normal voice band easily.

D.

 

[Nigel Goodwin]

Got me... I was thinking that the band was set aside for voice band communication... using frequency shift keying you can stay in normal voice band easily.

The mode of modulation doesn't matter - if it's only for voice communication you're not allowed to send data over it - not even by clever means that don't take any more bandwidth or anything.

 

[Sceadwian]

Technically voice signals are data... but voice communication means JUST that. The human voice non encoded. Not a bandwidth equivalent signal. Even encoding the human voice in the exact same bandwidth is out of lines with the uses set aside for a 'voice' band. Even using FM in the same bandwidth constrictions of an AM signal may be considered encoding as the modulating and demodulating methods are different even though the signal itself isn't.

 

[cadstarsucks]

Technically voice signals are data... but voice communication means JUST that. The human voice non encoded. Not a bandwidth equivalent signal. Even encoding the human voice in the exact same bandwidth is out of lines with the uses set aside for a 'voice' band. Even using FM in the same bandwidth constrictions of an AM signal may be considered encoding as the modulating and demodulating methods are different even though the signal itself isn't.

Well that's a bummer. That means you would have to get into the unlicensed science band. Maybe an R/C toy system encoded for safety?

D.

 

[Sceadwian]

It pretty much means you have to get a HAM license if you want to do stuff like that, because having a license allows you legal access to different bands for different uses.