I need to generate sparks between two pieces of brass, about a half inch apart or slightly more. I want each spark to be triggered by a logic line going high (going low would work, too.) The voltage supply is 6v or 12v from a battery. The problem is that I need the circuit to fit inside a 1.5" inside diameter PVC pipe, and not take up more than, say, 3" of the pipe length, discounting battery. I was looking at autotransformers, but I'm not finding anything that will fit in that space. I don't need more than 1-2 sparks a second, but I want the circuit to be reliable. Can anyone suggest a circuit design that fits in a small space like this?
I'm aware of the safety risks in generating a voltage high enough to cross 1/2" of air, and the spark won't be anywhere that a finger can get into it. If it wasn't for the voltages involved, I'd tinker something up by trial and error, but in this case I don't like the possible consequences of "error", so I'd rather get expert advice. I'm willing to wind my own transformer if that's needed. Thanks!