Firework ignitor

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New year is coming up soon and I want to let off a bunch of fireworks. However, every year I'm the one lighting the fireworks and I'm too busy running for cover to get a good view. This year I want to remotely ignite the fireworks!

I'm looking for a re-usable way to ignite them electronically using only standard batteries (9V or 1.5V) that can be triggered from 30ft away at least and won't drain the batteries in one or two launches.

My first idea would be to put a bunch of 9V batteries in series with a small loop of copper wire which I can attach fuses to, housed in a metal box. I could then set up a relay with a long control wire coming out of the box that I can press and hold a button to ignite the firework.

However, it's a bit primitive and I'm not sure it'll get hot enough to light a fuse. Anyone got a more elegant solution that's guaranteed to work?
 
You don't want to use copper wire for the ignitor, the resistance is too low and melting temp is also too low. Use nichrome wire if you can get it, or thin steel wire. A better battery to use would be a lantern battery or the battery pack from a rechargeable drill as these can provide more current than a 9 volt or other small batteries.
 
Drill battery sounds like a good idea. I can pick up a reasonably powerful battery drill for about £25 at a local DIY store. I have some cheese cutting wire that's made from stainless steel in my kitchen cupboard and I never use it. Random gift I got last year. I might butcher it and use that. It's only about .4mm in diameter, so it should have a decent resistance. I'll be using high-gauge wires within the ignition box so it won't fry the wiring inside the box.

I can't find any sources on the contact ignition temperature of visco fuses (the standard ones used in consumer fireworks), so I've had to do a little research. Visco fuses have a black powder core encased with around 1mm of nitrocellulose coated string. Nitrocellulose has an ignition temperature of around 170 C (and m.pt. is around 160 C) so I could do with 200 C on the wire to keep within a good margin of error.

Do you think a drill battery on a 20mm loop of .4mm steel will produce that kind of heat?
 
Most likely this will get too hot and burn up. you need thinner wire or lower voltage. A piece that long it would be best to use only about 1.5 volts, but high current. A piece that long will likely be only a few ohms.
I remember having a 6 volt NICAD battery as a kid that would burn up a section of iron wire about 0.5mm dia, 150 mm long
 
In my younger years, my friends and I used to use model rocket ignitors for such things. They are available in hobby shops. Just use a little tape to attach them to the wick of the desired firework(s) and then hook up your wires. Hit the button back at your ignition mechanism and the current flows. Ignitor lights wick and BOOM!!!:devilr: :D

Peace,

Dave
 
The only problem with this approach is the igniters cost more than the fireworks.

When I was at college, I fused an entire box of bottle rockets, roman candles, and a brick of fire crackers to a cigarette timer and placed it in the middle of an enormous parking lot. It was clearly visible from my my dorm room balcony. What a spectacle! The campus police arrived, but they had no way of knowing who was the perpetrator.
 
Sy, thanks for the reminder, I was trying to remember the trick a friend at work said he used to use. He took a small halogen bulb and broke the glass bulb off, without breaking the filament. Apply power to this and it gets plenty warm enough to ignite a wick.
I do agree that model rockets are fun. They are really just big, legal fireworks. And if you modify them correctly, you get a really big boom up in the sky!:D

Peace,

Dave
 
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Cool idea Dave, but would it work off a battery? Maybe if short enough.

What we used to do in the theater was take the screw in type houshold fuses (found in North America) and remove the tops. Break out the lead fuse part leaving only 2 tabs. A single thin strand of copper wire was wrapped around the tabs, making a circuit.

Then these screw in fuses where placed face up in normal ceramic light sockets. Fill with flash powder - connect to 120V via a switch and POOF! Big flash.
Cheap pyro. Do NOT try this at home.


Sooooo..... I suppose that bulk fuse wire is still for sale in the UK. Get the right gauge and it should/might work with a battery. Wrap a turn around each firework fuse. Cheap enough.
 
Hello Panomaniac, Not sure which of the ideas I posted you are referring to, the solar ignitor, light bulb or old toaster element. But I know that the solar ignitor works, that's what they are designed for, and I have done it. The light bulb idea came from a guy I work with, so it must have worked for him. Any of them will work as long as you have sufficient current. All you have to remember here is E=I*R and P=E*I. Use those to do some figuring and off you go. Or more accurately, off they go!:)

Peace,

Dave
 
I have once seen that the guys in the film busines that are igniting gasoline etc for special effects use car batteries, thick cables and aluminium foil strips to do the trick.

I personally once used a bunch of electrolytics charged to 60V and a thin copper wire (i.e. a single litz from speaker cable.

Regards

Charles


P.S.: In the old times of Kodak Instamatic cameras the flash bulbs used with these made nice ignitors that could be easily ignited with a 9V battery.
 
Try a single strand of copper wire cut from lamp cord. I know it works very nicely if you plug the other end into 120V; I suspect that a healthy 12V battery would light it up too. Use a pinch of black powder or maybe match head material to ensure the fuse lights.

Another option for delayed ignition is potassium permanganate and glycerin. The KMnO4 must be crushed to a powder. I used McDonald's straws as casings. The straws are oriented vertically, with the firework fuse taped into the bottom. Then, add some black powder to encourage the fuse, maybe wrapped in thin plastic to protect it from moisture or glycerin. Above that goes the KMnO4, maybe 1/4" high in the tube. Then, take the cotton from one Q-tip and poke that down the straw until it reaches the KMnO4, but don't tamp it hard. Wrap the lower part of the straw with masking tape to keep the sides from burning out before the fuse ignites. To use it, squirt an inch or so of glycerin into the straw, and stroll casually away. The delay as the glycerine soaks through the cotton and reacts with the permanganate should be several minutes.

Solar (brand) model rocket igniters were nice; they'd light with just 4 AA cells. I made up a little box with LEDs to indicate circuit continuity and a key switch for ignition.
 
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