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[on:]

Hello!

I am looking to film a short skit. I have an RF transmitter and RF receiver that I already can get working. I plan to press a button and   to wirelessly create a spark that will light something on fire! (i know, exciting). My question is how can I create a spark using the arduino. Obviously I would use the arduino to trigger something that would make a spark, but anyone have any ideas? I just need a spark to ignite a patch of gasoline or something along those lines. I dont need an actual full-fledged fire starter.

I'm planning to put the arduino far far away from where the fire will ignite. In the ideal world I'd have the end of a wire spark and that way it will be small and I can most certainly hide the wire somehow.  Ideas? I'd appreciate any feedback.

Nathan

[Reply #1 on:]

Using Auto Ignition coil with PWM
http://youtu.be/XIjpXSqnFig

[Reply #2 on:]

I think you'd better fill us in on the application before homeland security turns up at your door

______
Rob

[Reply #3 on:]

Use a transistor as switch like shown here http://www.rason.org/Projects/transwit/image1.gif (Its a pnp). Place the output pin of the arduino at base and pull it to ground when you want fire to start. And put  some steel wool at the place of load. Steel wool should act as short circuit load and draw a lot of current and thus a lot of power which will set it on fire. I haven't done it but I have seen people connect 9 volt battery with steel wool to burn it. Hope that helps!

See here for reference:
http://www.rason.org/Projects/transwit/transwit.htm

[Reply #4 on:]

Easiest way I know is to snap off the glass casing off a Christmas light and use the filament as an igniter.

[Reply #5 on:]

Yup, finely grind 2-3 match heads up and put them in the steel wool since you're limited anymore on what you can get without scrutiny or having the person who told you get even more scrutiny. Matches are still legal.. so far. If you can get strike-anywhere matches, those are best but you got to be real careful how you powder the tips.

It's a matter of current to turn the steel wool strands red hot but you can spot weld with 5V if you got the juice.
It just takes a LOT of 5V to spot weld. Steel wool is nothing compared. Experiment a bit.

[Reply #6 on:]

Scrutiny? I don't know how it is where you live, but around here we can still touch off up to 40lbs of black powder for "recreational use" (but fireworks are illegal here...). No permits needed as long as you don't use it to blow something up that could pose an environmental hazard.

You could use a model rocket igniter:
http://www.amazon.com/Estes-2301-Rocket-Igniters/dp/B000TF4DUO/ref=sr_1_1?ie=UTF8&qid=1322836701&sr=8-1

Or buy a small spool of nichrome wire (would be cheaper than steel wool)

Or use a commercial igniter. Pyrosure makes a fireworks igniter that complies with Canadian law: http://www.pyrosure.com/igniters.html . I have used them, they work quite well.


I just used a simple 2n2222 transistor and 2A mechanical relay to trigger the nichrome wire and Pyrosure igniters.

[Reply #7 on:]

You could just bend a piece of thin bare wire back and forth a few times and run some current through that if it comes to cost.

Black powder? I miss the days when I could keep a bucket of perchlorate and bag of 400-grit aluminum around. Sure, go far enough out and nobody would know but even ordering decent chemicals here is waving a red flag to the billions-of-dollars in private-industry profits police state.

[Reply #8 on:]

If you need a electric spark, the piezo spark from disposable fireplace lighters or disposable electric cigarete lighters might be an option. if you need an ignitor, any good terriorist site has various methods.

[Reply #9 on:]

I think you'd better fill us in on the application before homeland security turns up at your door

______
Rob

LOL

Reminds me of a circuit I made for a kid where I worked.  He said he wanted to learn electronics.  And that he wanted a game timer type of circuit to help him learn.  So I made a battery powered 555-based game timer with a DIP switch that would select various resistors to change the time delay.  I took great care in explaining the circuit, trying to help him learn and get excited about electronics.  He took it away happy and I felt good about instilling in him a desire to learn the field that I love.

Well, a few days later he said, "It's a good thing I tested that timer before I used it!"     I had tested it myself of course, and while demonstrating it to him.  "What do you mean?" I asked.  "Well, the output fires when you power it on, and if I had it hooked up to that pipe bomb at the time I wouldn't be here now!"

[Reply #10 on:]

If you need a electric spark, the piezo spark from disposable fireplace lighters or disposable electric cigarete lighters might be an option. if you need an ignitor, any good terriorist site has various methods.

Yes, all those terrorist websites like Ebay, Amazon, hobbytron, and Estes. Just use the commercial fireworks/rocket igniters. They're cheap, safe, and legal. If you really need a "spark" and not a "burn" you can use a disposable camera flash circuit to make a very large spark.

I would advise against using any kind of flammable vapor (gasoline, alcohol, ethanol). You're not going to be able to judge the size of the fire. If it happens to be particularly warm out, you could end up with a sizeable cloud of explosive vapor. Theres lots of examples on Instructables.com of people making arduino controlled propane fireballs for shows.

I did not see the bit about using gasoline when I first replied. Actually, I would advise against attempting this project at all. If you have to ask how to ignite it, then you don't have the experience required to do it safely, especially when other people may be near.

[Reply #11 on:]

If this is truly meant for the production of a "short skit" then you do not need RF transmitters/receivers/Microcontrollers, all you need is a pair of wires, a battery, and a model rocket igniter. This allows you to create your desired effect from a nearby location. If you need to be so far away that you can't run the wires then this is likely some other application.

Combustable vapors like those from gasoline require an open flame or a very hot incendiary such as burning phosphorous for ignition.

A "phone-it-in" device is severe overkill for a stage production pyrotechnic and building one without a permit SHOULD be cause for alarm.

If your application really is a video production pyrotechnic then save yourself the complexity and run two wires to a cheap hobbyist igniter over the fuel and use a battery in a remote location.

Do not try this indoors! and make sure to have a fire extinguisher, or the local fire department, on standby.

This sounds like a dangerous situation either way unless you are a professional.

[Reply #12 on:]

Yes, all those terrorist websites like Ebay, Amazon, hobbytron, and Estes. Just use the commercial fireworks/rocket igniters. They're cheap, safe, and legal.

At $2+ each plus postage, maybe not that cheap.

[Reply #13 on:]

Fashionable terrorists in this century use cellphones or electronic watches. Get with the times!

[Reply #14 on:]

If you want some drama use the arduino to run a motor to power a Van de Graaff Generator to give a spark to light the gasoline
http://en.wikipedia.org/wiki/Van_de_Graaff_generator

Be very wary of using gasoline indoors. A very small amount can create an explosive atmosphere that will put your film in line for a Darwin Award.