What are slats?

[rkmcdon]

I've seen mention and pics of slats to go with the cobra firing systems and am curious. What part do they play in a complete system?

[rkmcdon]

I was able to answer my own question (I think) by a quick search of Cobra's website. So basically a slat takes up one cue on your module. Everything on the slat fires together, but when you need a lot 18 cues fired at once, you don't take up 18 cues on the more expensive module

Hopefully someone can correct me if i have that wrong

Cobra slats (http://www.cobrafiringsystems.com/slats.html)

[cptnding]

I've seen mention and pics of slats to go with the cobra firing systems and am curious. What part do they play in a complete system?

Below is an example one one.
All of the connections for each cue are on the slat and the slat connects to a firing module via a cable.
That one is Cobra's but there are many different brands and styles. Generally speaking they are used most often on large shows with a LOT of cues.

http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=2893&stc=1

[cptnding]

I was able to answer my own question (I think) by a quick search of Cobra's website. So basically a slat takes up one cue on your module. Everything on the slat fires together, but when you need a lot 18 cues fired at once, you don't take up 18 cues on the more expensive module

Hopefully someone can correct me if i have that wrong

Cobra slats (http://www.cobrafiringsystems.com/slats.html)

Kind of.
The slat uses all of the 18 cues on the Cobra Module. You can connect an igniter to the slat and the module but it will fire both on each cue. You can also daisy chain more slats for more cues as well.
Example: Module -->Slat1 -->Slat2-->Slat3-->Slat4
In that example, when you fire cue 1, the number one cue on all 4 will fire. If you fire cue 14. The number 14 cue will fire on all 4 devices.
Hopefully that helps.

[rkmcdon]

Kind of.
The slat uses all of the 18 cues on the Cobra Module. You can connect an igniter to the slat and the module but it will fire both on each cue. You can also daisy chain more slats for more cues as well.
Example: Module -->Slat1 -->Slat2-->Slat3-->Slat4
In that example, when you fire cue 1, the number one cue on all 4 will fire. If you fire cue 14. The number 14 cue will fire on all 4 devices.
Hopefully that helps.

Oh, wow. So i was a bit off base. I was thinking 1 slat would allow up to 18 launches from 1 cue, but it sounds like one slat would allow you to fire two items from each cue.

Thanks from the clarification

[Rick_In_Tampa]

it sounds like one slat would allow you to fire two items from each cue.

Thanks from the clarification

Actually, that's not totally correct either. It's not a question of how many items you can fire from a cue. It's a question of how many cues fire at any given time.

In cptnding's example above a total of 4 cues would fire at the same time. But you could have 1,2,5,7 effects wired into each of those cues. So you could have maybe 28 different things going off at the same time! (A bit of an overstatement, but I think you get the point) Depends on how much power you have running through the system of course.

I hope that makes sense.

[displayfireworks1]

Now i'm confused. LOL I get questions like this from YouTube. People wonder how things work , this is why I tend to over explain sometimes. I can't tell you how times over the years someone ask me how many times can you use a single electric match. I once had a question when I said a "Fireworks Magazine" someone thought it was a special catalog we were ordering from. I remember back when I did not know much I heard the term Cross Match and tried to imagine what it meant. I try to remember these things when I explain something in a video.

[Rick_In_Tampa]

Yeah it was my understanding when I started this hobby there would be no math involved. Apparently I was mistaken.

After re-reading my initial post it appears I wasn't as clear as I could have been. My apologies. So let me try again.

Let's assume you only have one 18M firing module. If you daisy chain 3 slats off that one 18M, you now have 18 individual cues that fire in 4 different places at the same time. (All 4 number 1 cues fire at the same time. All 4 cue 2's fire at the same time. etc.) You are also still limited by the total power limitations for a single cue. So if you were only able to fire 6 e-match off a single cue before, you're still limited to 6 TOTAL e-match spread out over the 3 slats and 18M. So you can't fire 6+6+6+6. You could do 1+2+2+1, or 2+1+1+2, or 3+1+1+1, etc. and so forth.

I hope that makes more sense.

[rkmcdon]

Yeah it was my understanding when I started this hobby there would be no math involved. Apparently I was mistaken.

After re-reading my initial post it appears I wasn't as clear as I could have been. My apologies. So let me try again.

Let's assume you only have one 18M firing module. If you daisy chain 3 slats off that one 18M, you now have 18 individual cues that fire in 4 different places at the same time. (All 4 number 1 cues fire at the same time. All 4 cue 2's fire at the same time. etc.) You are also still limited by the total power limitations for a single cue. So if you were only able to fire 6 e-match off a single cue before, you're still limited to 6 TOTAL e-match spread out over the 3 slats and 18M. So you can't fire 6+6+6+6. You could do 1+2+2+1, or 2+1+1+2, or 3+1+1+1, etc. and so forth.

I hope that makes more sense.

Bingo! Alright, this one i feel i fully understand. This was my revised understanding after the first explanation, but it appears I wasn't very clear trying to communicate that back (two items from 1 queue just being true when using a single slat).

Thank you so much for taking the time to come back and explain it again!

[Pyro Paul]

I have 2 question in regards to cobra slats and in general. How exactly are the cables slats wired. I've been all over the cobra site and youtube trying to find a schematic. The reasoning for this is that I wonder if you need a shunt at the end of the line for slats wired in series. In my mind for the way the slats are supposed to work you would need something at the end of the line to connect the 2 series wires in the cable for the cue together in order to complete the series circuit. I hope this makes sense to someone knowledgeable... I'm thinking of ordering the 72m with slats later this year with additional slats and cables to do a 4 position AP front and want to be sure of what all I need to purchase. Also does anyone know the max amount of total cues a cobra 18m will fire on a fully charged 14.8 volt rechargeable battery? If say I wire the max amount of ematch on all 18 cues, will the battery handle it? (6 x 18 = 108 possible cues). After last years fiasco I'm trying to redeem myself this year, so I don't want to take chances.

[3 Fingers]

I have 2 question in regards to cobra slats and in general. How exactly are the cables slats wired. I've been all over the cobra site and youtube trying to find a schematic. The reasoning for this is that I wonder if you need a shunt at the end of the line for slats wired in series. In my mind for the way the slats are supposed to work you would need something at the end of the line to connect the 2 series wires in the cable for the cue together in order to complete the series circuit. I hope this makes sense to someone knowledgeable... I'm thinking of ordering the 72m with slats later this year with additional slats and cables to do a 4 position AP front and want to be sure of what all I need to purchase. Also does anyone know the max amount of total cues a cobra 18m will fire on a fully charged 14.8 volt rechargeable battery? If say I wire the max amount of ematch on all 18 cues, will the battery handle it? (6 x 18 = 108 possible cues). After last years fiasco I'm trying to redeem myself this year, so I don't want to take chances.

So on your question about the shunts....if you get SERIES slats from Cobra, they come with a shunt...and yes you do need the shunt.
Cobra also sells PARALLEL slats which are designed to work with talon igniters and they do not need a shunt.

As far as the question about how many you can fire with 14.8 volts, if you go to the Cobra web site you can find the tables with all the firing capabilities of each power supply for both ematch and igniters. I would also recommend reading the tables on the MJG Initiators as they are different that ematch.

[age2eod]

I have 2 question in regards to cobra slats and in general. How exactly are the cables slats wired. I've been all over the cobra site and youtube trying to find a schematic. The reasoning for this is that I wonder if you need a shunt at the end of the line for slats wired in series. In my mind for the way the slats are supposed to work you would need something at the end of the line to connect the 2 series wires in the cable for the cue together in order to complete the series circuit. I hope this makes sense to someone knowledgeable... I'm thinking of ordering the 72m with slats later this year with additional slats and cables to do a 4 position AP front and want to be sure of what all I need to purchase. Also does anyone know the max amount of total cues a cobra 18m will fire on a fully charged 14.8 volt rechargeable battery? If say I wire the max amount of ematch on all 18 cues, will the battery handle it? (6 x 18 = 108 possible cues). After last years fiasco I'm trying to redeem myself this year, so I don't want to take chances.

I'm new to pyrotechnics, so this question may show my ignorance in this field, but let me ask it anyway so I can learn either way. Also, I realize this is off topic, so feel free to move this to the correct thread if need be, it won't hurt my feelings, lol. However, In my experience, the only time you really WANT or NEED to use series wiring in explosives demo is when you have multiple charges that you need either ALL of or NONE of to function for a specific reason. In my military work experience we used a tool called a rocket wrench to remove fuzes from unexploded bombs. There were two counter positioned charges that when fired would create spinning motion in the direction of unscrew removal. This spinning action would unscrew the fuze from the bomb faster than it would detonate the charge if the fuze functioned upon initiation. You wouldn't want only one to function because that would produce an extremely hard off center torquing motion on the fuze, so we would wire in series so that if one charge misfired due to a bad bridge wire, neither would go off. Crappy day still because now you have to walk down range on a pissed off bomb that you just applied voltage to a charge connected to the fuze on. However, my point is: wouldn't you really WANT all of your other fireworks and effects to function in a show? This way you only lose that one effect on the cue rather than the whole entire circuit of effects on that cue? Plus series wired initiators present MORE resistance in a circuit as you add them, and you can typically function less of them than in parallel. So if a cue circuit can function up to 6 initiators in parallel, it may only reliably function 2 in series, obviously depending on your initiator and your firing module's capability. The other side of this is that if you had improperly balanced initiators, such that one presented considerably more resistance in the circuit, it's possible that one initiator could fire first, breaking the circuit and leaving the other initiator (s) without enough current for long enough to function, and now you have 1, 2, or (?) other initiators wired into effects that are all on a broken series circuit, and that will not initiate until physically rewired. Whereas all of the initiators wired in parallel will receive current for the specified length of time when that specific cue is fired. When would you ever want or need to use series wiring in fireworks display?

Misfires = owed beer cases, so we want to avoid them at all costs right?

[Rick_In_Tampa]

"When would you ever want or need to use series wiring in fireworks display?"

Personally, I always wire in series to avoid the possibility of a misfire due to a false continuity indication when wiring in parallel. Another good reason to wire in series is to eliminate/minimize the use of scab wire. If you want to run 6 effects off 1 cue (for example) and the effects are 20' away from the firing module, you just need to run 2 wires back to the firing module instead of 12 if you wire in series. Obviously, this only applies if you're using e-match or firewire initiators. They are designed to not melt and break the connection like the nicrome wire in a talon. If you're using talons you have to wire in parallel due to the design of the talon.

Does that make sense?

[age2eod]

"When would you ever want or need to use series wiring in fireworks display?"

Personally, I always wire in series to avoid the possibility of a misfire due to a false continuity indication when wiring in parallel. Another good reason to wire in series is to eliminate/minimize the use of scab wire. If you want to run 6 effects off 1 cue (for example) and the effects are 20' away from the firing module, you just need to run 2 wires back to the firing module instead of 12 if you wire in series. Obviously, this only applies if you're using e-match or firewire initiators. They are designed to not melt and break the connection like the nicrome wire in a talon. If you're using talons you have to wire in parallel due to the design of the talon.

Does that make sense?

Yep, all of totally makes sense. I guess the e-matches are designed that way for that reason. I guess I’m just used to electric blasting cap detonators, which utilize an exploding bridge wire, which helps add HSF to encourage the explosive materials inside the cap to move into detonation faster rather than deflagration and increases the chances of a detonation in your high explosives. All of what you said makes perfect sense to me though now and I can see why you would want to use series. Personally, I test all of my initiators individually prior to use so I know there’s continuity, but that’s probably not as easy to do for very large displays. In explosives demolition you typically only use two blasting caps in parallel and sandwich your priming loop on the detonating cord, and from there on out your shot is transmitted by explosive wave propagation through a series of det cord to different charges and you time your shots by how long of a piece of det cord you use. In EO demo usually you want equal lengths so the shots all detonate virtually simultaneously, or longer successively so they travel in a decided direction. The bridge wires in electric blasting caps never survive successful shots anyways as the HE turns them back into atomic particles, lol. I guess if you had a misfire you could test again with a galvanometer to see if your Circuit was open, but either way you’re buying everyone beer that night lmao.

[age2eod]

"When would you ever want or need to use series wiring in fireworks display?"

Personally, I always wire in series to avoid the possibility of a misfire due to a false continuity indication when wiring in parallel. Another good reason to wire in series is to eliminate/minimize the use of scab wire. If you want to run 6 effects off 1 cue (for example) and the effects are 20' away from the firing module, you just need to run 2 wires back to the firing module instead of 12 if you wire in series. Obviously, this only applies if you're using e-match or firewire initiators. They are designed to not melt and break the connection like the nicrome wire in a talon. If you're using talons you have to wire in parallel due to the design of the talon.

Does that make sense?

The only thing I might add is that if you wired in parallel you would still only need to run two feed wires out to your firing location, and you could tie them all together, but you would end up with the false continuity problem still though.

[Rick_In_Tampa]

The only thing I might add is that if you wired in parallel you would still only need to run two feed wires out to your firing location, and you could tie them all together, but you would end up with the false continuity problem still though.

Envision a scenario where you have 6 effects each 10' apart, all going back to the same cue on the same firing module. The wires on the two cakes furthest from one another would be (minimally)~ 56' apart taking into consideration the width of the cake itself. It would be impossible to wire them in parallel without using scab wire. But you could easily wire them in series.

Here's the layout for my show this year. Note the items connected with lines. They were wired in series. You can see how it would have been a nightmare to wire that in parallel and THEN run separate wires back to the mods. Just not practical. It took 13 hours to wire the show as it is!

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