Camera Flash Igniter

Email: sixmhz@yahoo.com
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Introduction

Since the birth of my web pages, I've had many inquiries about how to make an electronic ignition system from a disposable flash camera. In response to these requests, I've encouraged people to look into the high voltage flyback system instead, which, I believe is a better system. But for those of you who are determined to make a camera flash system work, this page is for you. I was fairly impressed on how easy this system was to put together and its reliability for firing. It also produces a quite impressive "bang" of a spark!

Overview

This page describes a simple way to use a disposable camera flash circuitry while minimizing additional components to create an electronic ignition source. Camera flashes typically operate by charging up a nice-sized (200-500 uF) capacitor to approximately 300 Volts. The capacitor electrodes are connected to each end of the flash tube. When the picture-taking button is pressed, another small capacitor is discharged through the trigger transformer. The trigger transformer then generates a high voltage pulse that ionizes a thin path between the two photo flash electrodes. This ion trail provides a low resistance path for the photo flash capacitor charge, which ionizes most of the gas inside the tube.

So basically, the flash circuit will be operating as normal with only one exception. The flash tube will be eliminated and the electrodes will be exposed to a fuel/air mixture environment.

Connecting to the Camera Flash circuitry

At this point I would like to mention that getting zapped by a 300 Volt flash capacitor is not going to feel too groovy. So please be careful and try not to make the current path go across your heart. We only need to make three connections to the flash circuitry. First disassemble your camera being careful not to destroy the mechanical shutter system as this triggers the flash. Next take out the battery and locate the main storage capacitor in the camera. It should look like a cylindrical fellow, shaped kind of like a battery. Once you have found this guy, make sure it is discharged by shorting its leads together with a screwdriver. This is gonna make a big ball of sparks if it was charged up, so be careful. Now you need to find the flash tube and remove it. Now I donít mean remove it with hammer, you need to be gentle. There should be two connections to the tube itself, these are the leads from the main capacitor. Unsolder the flash tube and solder in some wires where the tube used to be. These two wires will go to your electrode system and will carry the charge from the capacitor to the spark gap. Keep these wires short and use a moderate gauge of wire.

Once the flash tube has been removed, you need to find the trigger transformer output. The trigger transformer output should be a wire soldered to the flash tube reflector or wrapped around the tube somehow. Solder a wire on to this guy or to the reflector itself. This wire will also go to your electrode system and will initiate the spark. Keep this wire away from any other wires or circuitry as regular wire insulation is not rated for the voltage that this will carry.

Electrode Configuration

Now we need to make an electrode jig to put inside the combustion chamber. Basically weíre just making a tubeless flash electrode setup. I recommend using some solder pad perf board from your favorite electronics store for this part. For this system we need three electrodes, two for the capacitor and one for the trigger transformer. Since the arc will occur at atmospheric pressure, we need the electrodes as close each other as possible. The trigger electrode should be in the middle, pointing straight up from the perf board. The two capacitor electrodes come in from each side, perpendicular to the trigger electrode and pointing at each other. The tricky part is getting the electrodes close enough so that it arcs, but they cannot be touching. They need to be really close together, so close that they almost look like they are touching. Click here to see what mine looked like although they're a bit burned up.

At this point the flash circuit should be hooked up to the electrode jig to make sure the spacing is right and all. If it doesnít work here, itís not going to work inside the chamber. Solder up some wire leads to the three electrodes so you can connect them to the flash circuit. Try to keep these wires as short as possible and use a moderate gauge of wire for the capacitor leads to minimize resistance. It doesnít matter which capacitor lead goes to which side of the electrode jig, as long as the trigger transformer is in the center. So charge it up and adjust the electrodes till you get a nice fat spark. Just be sure to remember to discharge the capacitor before you adjust the electrodes. I'd also like to mention that even if it does "fire", the capacitor will still have like 50 volts across it just waiting for an unexpecting victim.

Feedthroughs

Since the electrode jig will be inside the chamber we'll have to make some feedthroughs to get the electrical connections outside the chamber. This can be done by using some small nuts, washers and bolts. Take the three wire leads soldered to the electrode jig and connect the other ends to three bolts by squishing the wire in between the bolt head and a washer with a nut. Now drill three holes in your combustion chamber and feed the three bolts through from the inside, and put another nut on the outside. Might look something like this and this.

Outside Connections

Once the electrode jig is inside the chamber, you just need to hook the circuit back up to the leads sticking through the chamber wall. Thatís it, now go send some spuds into space!

My System

I used a Kodak Max camera that RI John gave me (Thanks John!) but any one should do. The Kodak Max diagram comes CRAZY ANDY's site http://www.geocities.com/lemagicien_2000/ , a lot of crazy shit going on there. Since I didn't want mine to look like total crap, I made a nice home for it in a plastic box and wired in switches to charge and fire. I also extended the neon lamp leads so that I could see when the capacitor was charged. I used some size 10 screws, nuts and washers to make feedthroughs to carry the three electrode connections outside the box. The second photo is a shot of this sparker in action inside a 4Ē diameter ABS combustion chamber.

Issues and Potential Problems

So what's wrong with this design? Well here are a couple of points:

DISCLAIMER

The author assumes no liability for any incidental, consequential or other liability from the use of this information. All risks and damages, incidental or otherwise arising from the use or misuse of the information contained herein are entirely the responsibility of the user, have a nice day!

Last updated: 5/08/03
Copyright 2003, Greg Miller
http://www.angelfire.com/80s/sixmhz/camera.html