I need a circuit to create a spark for ignition.

[khaag]

I built this little potato gun, the whole thing is about 9 or 10 inches long, just a little guy. Problem is, a regular BBQ sparker that I'd use normally is too big for the gun. I need some way to create a spark for ignition. I'm hoping i'll be able to create a little gap for a spark to jump across when I press a pushbutton switch letting the current from a 9V battery start the ignition.

Something like this:


Also I need it to be as small as possible. Any suggestions?

[jjhammerstein]

You could try that. XD

[samjc3]

i dont think that 9v battery will arc. instead, wire it through a piece of ultra fine steel wool. that way when you push the button, the steel wool sparks, and potato goes bam, into the field 100 yards away!

and post some pics!

[jjhammerstein]

That would only work once though. Use a spark plug and a higher voltage, maybe? It'd look cool with a spark plug sticking out of the top.

[palmertech]

Make one from a disposable camera.

Want a pic? I can have them in about 20 minutes.

Runs off 1x AA, too. I use a D battery for longer life, though.

EDIT: For that size, just grab one of those long tipped BBQ lighters. Whenever you press the button, it makes a small spark across the sparkgap. They are about the size of a stack of 4 quarters (The ignitor, that is)

[bicostp]

Camera flash. Go down to CVS and ask them if they'll give you a spent disposable.

[Skyone]

DO IT.

[samjc3]

DO IT.

seconded!

[Kurt_]

Yeah. Flash capacitor was the firs tthat came to mind. A trigger that touched the wires would do the job.

Optionally, a small amount of steel wool and a 9 volt would do the trick.

[RockNRoll!]

If you're gonna use a flasher, you need something to touch the contacts together in the combustion chamber because the voltage isn't high enough to spark over a gap. If you want a high voltage spark that will fit anywhere, take the sparker out of one of those pistol-ish clicky lighters. They're tiny and make a nice spark that can cover a 1cm gap.

[beeps8]

Use this, never fail

http://www.idealtruevalue.com/servlet/the-52139/Detail

[Kurt_]

With that you have to be right next to the cannon when it goes off. If anything should go wrong, that's not where I'd want to be.

Why not some tungsten for burnt out soldering irons? That'd work wonderfully if you found a good temperature to keep it at.

[palmertech]

You do NOT need a way to make the contact touch. The camera flash button triggers a high voltage pulse to a wire that ionizes the flash tube, allowing the main capacitor to discharge into the tube, making a flash. Just take the two leads from the capacitor, hook them up to screws really close together, then use that thick wire soldered to the flash reflector, solder a needle to in, and position it between the two capacitor terminals. Whenever you press the fire button, it make the air between the capacitor discharge terminals conductive enough for the gap to be jumped by a bright blue spark, along with a SNAP sound.

[khaag]

Yeah, I think the camera flash will be the best bet. Although, a long-necked BBQ lighter would do well too, as it could be implemented into a handle/trigger type dealio.

[palmertech]

I PROMISE pics of my mini gun tomorrow morning. You can use it as a reference.

NOTE: It sucks, I made it like two years ago, before I was good at the cosmetics. Still works, though.