Sparking Pumpkins

Unless you want the entire pumpkin burning, you'll need to add internal wiring, and some sort of metal points on facing sides. Like maybe grind the head of a 16d nail shiny, cover shaft with shrink wrap, and shove through the face, and connect the ends inside the pumpkins. Set the pumpkins on some sort of insulating material, like dry wood.

Recommend you put the setup out of the reach of young fingers, lest the parents hiding in the bushes start calling the cops on their cell phones. Dunno how far the sparks will jump- been decades since I played with one of those transformers. Ask over in one of the electronics groups- those guys know everything.

How about one of those toys that uses a rough wheel to rub against a piece of flint? It could probably be motorized easily.

Art's idea is MUCH safer, the neon transformer will kill very readily, that's what they use in bug zappersa, only on a much smaller/lower scale. You don't want to have to explain on national tv how you killed a trick or treater.

A neon transformer has high voltage, but almost non existent amperage. They will ring your chimes if you are grounded, a bit like a spark plug wire but I wouldn't classify them as deadly.

If the OP could rig one to spark and arc intermittently, it could be quite showy.

Two words...well, three ( :) ) -- electric fence charger...already rigged up.

Doing the math in my head, as I "grew up" knowing this in cm, but I think around 80kV/inch in air is around the right sort of number.

It's possible to 'draw' the spark out to a much longer distance (e.g. Jacob's Ladder) - and a neon sign transformer or TV/monitor flyback should work well there, but that's not really the effect you're after...

I agree with others, though, there's a fire hazard here - not to mention that HV can be pretty painful; if you do make something, make sure it's not 'accidentally' accessible.

I remember making a spark-gap generator when I was about 15; I built a waveform generator running from a 9V battery and used the HV transformer from an old camera flash for the step-up. It was reasonably effective for zapping friends with and gave quite a jolt (ahh, the days of being young and foolish, rather than old and foolish!), but based on the spark length I was only getting about 10-15kV out of it.

cheers

Jules