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Camera Flash Ignition

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Unread postAuthor: jimmy101 » Wed Jun 27, 2007 12:39 pm

mark0491 wrote:they dont have to have a gap 2 nails could just touch each othe and have huge sparks. also they can use a flyback Trigger system so Dont say this wont work because i know it works.

Yes, it'll work. Once, maybe twice or even three times. Then your contacts are burned and the "gap" will have to be readjusted.

BTW, this "." is a period. It is often used when trying to communicate in a lucid fashion with another human being using the English language.

Care to go into more detail on the use of a "flyback trigger system" with a photocap? People appreciate lucidity in replies to their questions.

You can certainly dump the photocap through a flyback transformer (salvaged from a TV) and get a pretty substantial output voltage. (Assuming you don't fry the primary coil on the flyback.) But that set up isn't a "trigger" system. You could use the flashtube and the trigger circuit (a low ESR cap and a tiny 10KV coil) already on the flash board as the switch/trigger system to apply the photocap's energy to the flyback transformer.

To actually get that to work, Spudbud101 would probably need more info than you provided.


Spudkilla, I also saw that post but can't find it now. Can anybody find it?
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Unread postAuthor: mark0491 » Wed Jun 27, 2007 12:50 pm

oh jimmy im sorry i figured the wiki article had enough information on it, and the fact that i did use a period is because i was in a rush to get of to work im on my break now and i can type correctly. So if you wouldn't mind insulting someone before you hear the story. :!: :!: :!: :!:

Quote from wikipedia "

camera flash can be used for spudgun ignition in several ways, either by itself or by feeding the high voltage from the flash capacitor through a step-up transformer (commonly an ignition coil, flyback transformer or a mains transformer in reverse).

The main advantage of camera flash-based ignitions is that it can be built using cheap, readily available components. The spark is more powerful than that of a piezoelectric ignitor. A camera flash is usually powered by one or two AAA or AA cells. Disadvantages include several seconds of recharge time before the ignition can be triggered again, and significant shock hazard from the storage capacitor if built improperly. Special care should be taken when used in metal launchers, as both sides of the storage capacitor can have significant voltages between them and other parts of the circuit, such as the battery poles and the trigger switch.
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Unread postAuthor: mark0491 » Wed Jun 27, 2007 12:56 pm

Thier are also these ways.
"Tube Switched Coil

The ignition that requires the least modification of the camera consists of cutting one of the main leads to the flash tube, and connecting the ignition coil in between. Triggering the flash will produce a spark from the output of the transformer. The advantage to using the flash tube itself to switch the main discharge, is that almost any small switch can be used to trigger the circuit. If the trigger switch is replaced by a thyristor (SCR), the ignition can be triggered by an electronic circuit. The flash circuit itself is mostly intact and not driven out of spec, which means this circuit is quite reliable.
[edit] Manually Switched Coil

The flash tube can also be replaced by a heavy duty switch for triggering, though if the switch is too weak it may become welded shut. This switch will also be carrying the full voltage of the capacitor, and must be properly insulated to prevent electric shock. If the trigger switch is held down for a long time the charging circuit in the flash may break since its output is shorted for the duration.
[edit] Triggered spark gap

Another ignition method that does not require an external step-up transformer, consists of removing the flash tube, and taking out the trigger lead as well as the two main leads. These are then connected to three electrodes, which are placed together to form a spark gap of a millimeter or less. Triggering the flash will ionize the air in the gap and discharge the main capacitor. This produces a more intense spark than the first method, but it requires a more complex park gap. The electrodes can also erode over time, requiring readjustment.
[edit] Trigger transformer spark

The trigger transformer for the flash tube produces a few kV on its own, and can be connected to a spark gap. The advantage to this method is that the main capacitor is not dumped, so recharge time is eliminated and it uses less battery power. The spark is very weak however, and this method is generally not recommended.
[edit] Short circuit gap

A camera flash can be used with a short circuit gap, which has movable points that can be brought in contact from outside the chamber. The flash capacitor is connected directly to the gap and creates a spark when it's shorted. This spark gap is more difficult to make, and may have isues with weldong and erosion, but is easy to hook up and requires little electronics knowledge.
[edit] Others

A camera flash can also be used to trigger sprinkler valve solenoids built for mains voltage, however the opening time will be brief since the flash capacitor is drained quickly. "



Also you can look here http://www.angelfire.com/80s/sixmhz/flyback.html
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Unread postAuthor: jimmy101 » Fri Jun 29, 2007 1:24 pm

mark0491 wrote:Oh jimmy I'm sorry. I figured the wiki article had enough information on it. <strike>and</strike> The fact that I <strike>did</strike> didn't use a period is because I was in a rush to get of to work. I'm on my break now and I can type correctly. So if you wouldn't mind insulting someone before you hear the story. :!: :!: :!: :!: etc.


So, replace all that follows with a link to the Spudwiki photoflash page (not wiki). The original poster would have gotten his questioned answered in a clear fashion.

Just jerkin your chain mark0491. But it really is annoying to read posts that are so poorly written that you can't figure out WTF the person was trying to say.
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