6-21-07 UPDATE: Added an SCR into the circuit (new button; the old one short-circuited). Details on the SCR on step 3.
Step 1: Enter at Your Own Risk!
Looking back on this instructable, I realize there are numerous fatal flaws in the design. Some recommendations:
-A more stable (and much faster and effective) CHARGER
-At the current time, I'm pretty sure the SCR in this design will, *ahem*, explode the way it is implemented. One with higher voltage/current abs. max ratings is necessary, or you can use a technique called "Paralleling, Anode to Anode, Gate to Gate, and Cathode to Cathode" (I'm quoting an excellent site for coilgun reference HERE ). Pardon my engineering but I think it was about 15 when I did this instructable.
Good luck and have fun!
Step 2: Parts List
-project box or some other sort of enclosure (I used a RadioShack one)
-disposable cameras; the more, the better (in this case, 14 of them)
-1.7V volt or VERY low consumption LED (I used a RadioShack 1.7V red LED)
-binding posts (those screw-down thingies on the outside of the box) RadioShack catalog #274-661 or equivalent (you will need 4)
-2x on/off switches (I used what I had; PCB (PC Board) ones.
-some wire (In this case, I used 22 guage, but I think you can use a lower guage even though there will be high voltage/current; it's only split-second bursts)
-batteries and holders (maximum 6V)
-large on/of rocker switch (optional for protection)
-soldering iron & solder (you CANNOT just wrap the connections; they need to be permanent and well-connected for this project)
-electrical tape (masking tape WILL NOT suffice)
-Drill and Proper Bits
Step 3: Make/Connect the Capacitor Bank
Step 4: Build and Enjoy!
6-21-07 UPDATE: Below is the SCR (Silicon-Controlled Rectifier) that I salvaged from a light dimmer (model no. Q2008LT). Basically what it does is, it triggers the capacitors to discharge when it receives a small pulse of electricity above ~.5V. This way, the only electricity going into the switch is just as low as the power source you use to trigger the SCR. You can find SCR's in certain electronics, or you can order one online for less then 50 cents, BUT BE SURE NOT TO CONFUSE SCR'S AND VOLTAGE REGULATORS (and triacs); THEY BOTH DO TOTALLY DIFFERENT THINGS, BUT THEY LOOK EXACTLY ALIKE!! Also, don't worry about the middle pin; we won't be using it.
Using the circuit I provided will, unfortunately, ruin your switch and make the coilgun inefficient. But by using the new setup with the SCR, it will work much more efficiently. Be sure to take a look at the schematic (the 2nd one)!
NOTE: Elaborate on the diagram; I have not updated it to reflect the added components.
6-24-07 UPDATE: DO NOT USE THE SPECIFIED MODEL OF SCR; IT IS ACTUALLY A TRIAC (different kind of device; looks the same). Try using one of the SCR's on THIS page.
Step 5: The Finished Product!
6-21-07 UPDATE: The first picture is the new, revised coilgun.
Step 6: Some Tips
-Keep the flash in; I do not know why, but when I removed the flash, the caps did not charge. I tried removing the flash AND bridging its connections, and it still did not work. Just leave it in. If you figure out this odd ghost in the machine, let me know.
-When you extend the indicator light to the outside of your enclosure, you don't need to buy and LED IF (and ONLY if) the chip already has one. I would not recommend trying to fuss with a glass neon bulb. They can break.
-You can add a safety switch, which would be in line with the power in wires (and keep it on the inside of the box), so if you don't want anyone messing with it, or just for safety reasons, you can turn it off, so even if someone connects power, nothing will charge.
-MAKE SURE you connect the capacitors properly. If you don't, they WILL explode. Also, be sure o connect the in PARALLEL, not series (Parallel is + to + to + to + and - to - to - to -; so on and so forth. Series is + to - to + to -; so on and so forth). If you do not do this, they will not charge sufficiently.