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Flash circuit

Posted: Sat May 14, 2011 12:38 pm
by warhead052
I was wondering if there was any way to make a flash bang out of a flash circuit. If so, how would I go about making one? I found this on youtube, and I like the design and the idea. Does anyone know how to make one? http://youtu.be/-mHGeKsJSu8

Posted: Sat May 14, 2011 12:48 pm
by Fnord
Yes, it's possible assuming you don't need the 'bang' part.

Posted: Sat May 14, 2011 12:56 pm
by warhead052
I don't need it. How would I go about making one? I have no clue how these work, so yeah.

Posted: Sat May 14, 2011 1:16 pm
by Fnord
It's probably best if you have some basic electrical knowledge first.
A camera flash uses a small flyback transformer to boost 1.5v dc (battery current) to ~300 volts which is stored in a capacitor. When you hit the trigger circuit, a small single pulse is sent through another transformer which boosts it up into the kilovolt range. This HV charge passes through the walls of the flash tube, ionizing the gas inside. When this happens, the gas becomes conductive, and the 300volt charge stored in the capacitor flows into it, causing it to heat up and glow briefly; the 'flash'.


Now, how can this be amped up for a flash-(notbang)? I guess you could try adding more capacitors to increase the flash intensity, though as I said, it would be nice if you have some electrical background first. After 3 or 4 capacitors you start getting into dangerous current territory, meaning it could kill you if you screw up.

Posted: Sat May 14, 2011 1:53 pm
by saefroch
Even a single photoflash capacitor discharging through flesh will cause internal burns. If you have limited electrical knowledge, be very careful.

Posted: Sat May 14, 2011 7:18 pm
by jimmy101
You can fairly easily make the bang part. A trigatron in a short length of pipe will make a respectable bang when it is triggered. Not as loud as a firecracker but pretty loud.

A trigatron is just three electrodes: two for the 300V from the photocap and the third is the flash tube's trigger voltage. Works just like the flash tube, though a bit tricker to actually get it to work. The trigger spark ionizes the air in the main gap and when the photo cap dumps it's 5J or so of energy into the spark it makes a bang. Put it in a short (couple inches long by couple inches wide) piece of pipe and the pipe will amplify the sound of the spark.

http://www.angelfire.com/80s/sixmhz/trigatron.html

Edit: a 3" diameter piece of PVC works well for the electrode holder and obviously you don't want to use a metal pipe.

Posted: Sun May 15, 2011 3:38 am
by qwerty
It says his YouTube name is potatoflinger. Ring any bells? He has videos on homemade airguns too so i guess he is a member of SF. Ask him.

Posted: Sun May 15, 2011 6:10 am
by Technician1002
If you really want a bang, make a home built high pulse current speaker to place in series with the cap discharge path. A rare earth magnet on a tin can lid with a 3 or 4 turn coil next to it will make a bang with a high current discharge.

Posted: Sun May 15, 2011 10:35 am
by warhead052
Qwerty, I recognize the name.

Tech, its not so much the bang, that can be achieved by a simple mix of blur with blur (mythbusters quote.).