Can I get a spark on demand?

[SilentJ20]

Hello everyone. Been around SpudTech a bit but since it's closed, this is where all the knowledge is at.

I don't know too much about electrical circuits. With a stungun, the button is pressed, capacitor charges and then a spark is formed many times a second as long as the button is held. Is there a way to create a single spark with the press of a button? So every time I press the button I'll get just one spark and one spark only exactly when the button is pressed. I'm interested in electrical--not piezo--from a 12V source. Maybe an adaptation of an automotive coil perhaps? Any help would be appreciated.

Thanks.

[jimmy101]

Why do you want a single spark? Multiple sparks don't cause any harm (they also don't really help anything).

[SilentJ20]

I suppose it could spark multiple times as the button is held. I'm really just needing a single spark, and more could be a nuiscance. It's for a project where timing of the shot is important. I suppose it could be slightly delayed as long as it was consistent. I was looking at some "High Voltage Trigger Sources" online, but I couldn't tell if that fit my needs. And they were expensive.

[paaiyan]

I know there's a setup you can build to build up a huge static charge and then release it on demand, but I haven't got a clue how to go about it.

[Freefall]

Look into the ignition systems based on the disposable camera flash units. I've never built one, but I'm sure that there are others here who could point you in the right direction.

[SilentJ20]

I've read up on camera flash ignition, but it sounds like there is a recharge time. I was hoping for somewhat rapid-fire, maybe a few times a second. For the experienced, could a component of the camera flash be added or removed to speed up the charging, perhaps? Thanks for the info so far.

[iPaintball]

You should install a capacitor with a lower capacitance rating.

[paaiyan]

I've read up on camera flash ignition, but it sounds like there is a recharge time. I was hoping for somewhat rapid-fire, maybe a few times a second. For the experienced, could a component of the camera flash be added or removed to speed up the charging, perhaps? Thanks for the info so far.

Wait wait, if you want rapid fire then why not a stun circuit?

[Hotwired]

I've read up on camera flash ignition, but it sounds like there is a recharge time. I was hoping for somewhat rapid-fire, maybe a few times a second. For the experienced, could a component of the camera flash be added or removed to speed up the charging, perhaps? Thanks for the info so far.

Hm.

So you want a single spark per trigger pull BUT you want it to be able to repeat that several times a second.

Why?

If you want faster charging from a camera flash circuit you take out the large capacitor and insert another one of the same voltage but lower capacitance.

[iPaintball]

If you want faster charging from a camera flash circuit you take out the large capacitor and insert another one of the same voltage but lower capacitance.

Hmm Hotwired, that sounds vaguely familiar...

[SilentJ20]

Alright I'll give a hint. I know a lot of people dream of this and plan it out in their heads, and I've been doing some planning and dreaming of my own. For a high-rate-of-fire spud gun . I've been researching all the components necessary (main mechanics, fuel delivery, ignition system, ventilation, etc.) and the ignition system has eluded me so far. That is the reason I want a high-rate, on-demand spark system. Timing is important and that's why a non-metered barrage of sparks won't cut it. Call me crazy for planning a spud-machine-gun, or call the idea a mere pipe dream:roll: , but it's something I'm interested in.

[Hotwired]

You think you can knock up something to fuel, allow for the combustion, ventilate and refuel several times a second?

Actually, come to think of it, I can - a car engine does that all the time - but you'd need another power source to drive the cams for the valves.

Oh yes, cams would allow you to do the sparking too, every time the cam goes round you could have it flip a switch to pulse 12v through an ignition coil.

The trigger on the gun could start a motor to get a shaft with several cams on it or gears to other cams which would alternately open valves and switches for fuelling, sparking and ventillating.

You'd end up with something like a minigun but hey, thats not such a bad thing.

[paaiyan]

Well you could replace the momentary switch from a stun circuit with a switch from Radio Crap or something. You can probably get hold of a non-momentary push button. Just ask around an electronics component store if there's a button that will only connect the circuit for an instant. I'm sure they make one.

[SilentJ20]

I may do just that. I've messed around with the stun gun on the gun I have and when the button is pressed, it takes a bit for the capacitor to charge and then spark. Not long, but it's noticable. Also, if the button is held down for a bit too long, it partially charges the capacitor and when the button is pressed again, it finishes charging and sparks sooner than the first time. It's not consistent. And when the battery gets low, the rate-of-spark slows down. Maybe I have a crap stun gun and it's different than others.

[paaiyan]

Perhaps a switch like this one. http://www.radioshack.com/product/index ... age=family