Coil Gun

Seems an odd way to have the coil for an electromagnet, I used the innards of a Ford starter solenoid. I used an 400V 820uF cap charged to about 300V. I used a PIC (of course ;-) to generate the PWM signal and measure the cap charge thru a resistive divider. For the switching transistor, I used an IGBT. An SCR dumped the charge into the solenoid. On a good launch, it would throw a computer case screw across the room.

The 'fun' bit comes, when you have multiple coils, and capacitors, and add opto-detection of the projectile, to fire the next coil. Once the speed gets up to a few hundred m/sec, the timings begin to get quite critical. Large flash-gun capacitors work quite well.

Best Wishes

On a sunny day (Tue, 27 Feb 2007 08:01:38 -0600) it happened "Anthony Fremont" wrote in :

Or use a slingshot, like the Tijuana police:

The reason I can see for using ferrite cores this way would be to protect the mosfet, as they moderate the current a bit. Apart from the fact that a simple solenoid wouldn't look that impressive!

I'm referring to direction of the wrapping with the core being parallel to the windings instead of perpendicular. AFAIR, I have never seen an electromagnet constructed this way.

They are not exactly parallel. So there will be an effect, but not better than a single turn the usual way, except from the moderation.

Wheelnuts as projectiles - great deterrent to rampaging hoodies.

Here's a guy shooting 30 caliber projectiles with his coil gun.

Interesting 16 Stage Optically Triggered Prototype with opto-sensors.