The Electromagnetic Projectile Launcher

almost through a can! (320V)

straight through two layers of cardboard! (320V)

i finally got it to shoot! at the cost of an IGBT. proof of concept that it works.

i loaded the projectile ~1/4 or 1/6th of the way into the coil.. charged the caps to ONLY 100V

triggered the IGBT, and out goes the projectile hitting the box what it looks like to be almost perfectly square on. the box actually had two layers of really good cardboard so it didn’t puncture the box completely… and it knocked the box over and the projectile bounced back to the wall..

the coolest part: SILENCE leaving the barrel… on firing.. you just can barely see it exit.. and the next thing you know.. a pop (when the projectile hit the box) and the box tumbling over in front of you…

pretty cool @ only 100V..

i’m gonna pick up a relay from jesse tomorrow to see if that will suit my needs as a trigger… we’ll see. (for the second stage though i think i would still need and SCR/IGBT as a relay wouldn’t trigger fast enough)

this is what a 200V spark did… (note to self: jesse was right.. i need saftey glasses)

—

what happened:

i tested the coil that I made with a 1.5V (D-sized) battery (pictured below with the coil) to make sure it was magnetic. (it was =]).. (btw, the measured resistance of the coil is inbetween 3-4ohms)

i then bought an SCR and wired the anode/cathode in series with the coil with the capacitors in parallel. the gate was connected to a wire which i would manually connect to a 12V line in series with a 1k resistor.

i charged up the capacitors to 250 volts.. turned off my charing circuit… loaded my projectile into the proper location (1/8 of the way entering into the coil). and connected the gate of the SCR….

NOTHING..

i examine the circuit… everything is in order.. i check the voltage over the caps to make sure they’re still charged and they are… i wonder what went on… i unplugged the + on the caps connecting it to the boost converter and accidently left it hanging.. and second later while examining the circuit… a HUGE spark and a HUGE noise (sounded like a really big high pitched firework)..

i got discouraged and stopped working for the night..

this is the damage it left on the breadboard.. the hanging +’ve line scrapped against the ground… and it STILL left a 50V charge over the caps…

It took me forever to properly wind magnet wire…

—

This is how I did it… (with the stuff I had in my room)

I took a screw, used a hacksaw to chop of the end of the screw.

I then wraped some duct tape over the screw so that it would provide support for the barrel as the screw is around a hundreths of an inch too small to be a perfect fit.. (the problem i was running into before caused my wrapping to compress the barrel and therefore causing more friction and my projectile to get stuck inside the tube)

I then cut my tube/barrel to the size of my desired coil, slipped it over the duct tape (forcefully, if it didn’t take force.. i think the tube would’ve been compressed again).. and then wrapped the barrel with 2 pieces of regular notebook paper so that i could slip the tube off and stick it on my real barrel..

i had two washers on the side that fit on my barrel perfectly…

then had to end thingys that acted as lockwashers…

weeee, i made a coiling jig without having to goto the hardware store..

to wrap.. i just wrap as tightly as possible and the picture is what you get!

i wrapped 8 layers and is ~>1inch in length

Boost Converter, perfect test! 360V is less than a couple seconds.

Boost Circuit testing!

Perfect 555 timer waveform, double checked with oscilloscope.