A tutorial explaining how to build your own coilgun from some disposable camera's flash circuits.

It doesn't require much money (if any), but you need some basic soldering skills and electronics knowledge to finish it successfully...

If you have any questions don't hesitate to ask me!

Step 1: Getting the Parts

What do you need

- About 5 disposable cameras (used) with flash circuit (you can probably get them for free at your local photo-store if you ask nice)

- A soldering iron

- Some wire

- A plastic ballpoint-pen, ink tube removed so you only keep the hard outer plastic tube

- A light-switch

- Electrical insulation tape

- Plenty of enameled magnet wire (ca. 0,5mm diameter)

- Some soldering skills and some electronic knowledge

Step 2: Disassembling the Cameras and Getting the Right Parts

- First of all, disassemble your cameras and carefully remove the flash circuits.

- Look for the big capacitor on every circuit board (a cilindrical thing) and touch both connections with a screwdriver. BE CAREFUL! This will probably give a great spark, since the capacitors may still be charged.

- Choose the flash-charger-circuit board you want to use. Mark the location and the polarity of the capacitor on the board, so you know how to connect the string which will be explained in step 5 later. The (-) side is the one with the vertical stripe printed on the cap above it.

- Identify the charging-button and triggering-switch on the circuit board which were originally used to load and trigger the flash, and solder the wires connected to them together, so the switches are both closed.

- Desolder the big capacitors from every circuit board, and throw away the boards you don't need - so not the one you chose earlier.

Step 3: Preparing for the Real Stuff

- Connect the capacitors in parallel, that is, connect the (+) and (-) sides to the (+) and (-) sides of the other caps. This is performed easily by using a universal circuitboard.

- Connect the string of caps to the connections on your flash-charger circuit board you marked earlier.

Step 4: Assembling the Coilgun

- Desolder the wires connected to the flash tube (and to the reflector attached to it) and mark the places where the two main wires were.

- Wind a coil using the enameled wire and the plastic ballpoint-pen. Do this by turning the wire around the tube. The coil should be about 2,5cm long. Wind several (about 10) layers on top of eachother, but don't forget to insulate each layer with electrical tape.

- Scrape off the coating of the enameled wire at the ends of your coil; enameled wire-coating isn't conductive

- Solder one end of the coil to one connection where the flash-tube was before. Solder the light-switch to the other end of the coil, and the other end of the light-switch to the other flash-tube-connection.

Step 5: Finishing It

- Make sure the light-switch is switched off. Now attach a battery (1,5 to 9V )to the wires (use the same connections as these which were there before you modified the circuit; so that are the connections to which the original camera battery was attached.)

- Wait untill the circuit board's status LED lights up, then disconnect the battery.

- Put a load (small nail, metal rod,...) in your coil (inside the pen-tube, that is) and put the light-switch on. The load should be shot into the room!

- FINISHED. Have fun with your coilgun!!