electromagnetism

I'm working on a coil gun and the only real issue I'm having is shutting off the coils after launch, are there any alternatives to buying several arduinos or pi's and program them all? I want to have to do a whole lot of code work.

>>4907 BIG BUMP

>I'm working on a coil gun and the only real issue I'm having is shutting off the coils after launch just flip the off switch...

>>4910 then I have to power the whole thing back on every time I want to fire another round.

>>4907 Can you be a bit clearer about what you are talking about. Why would you need multiple pi's or arduinos and not just one, are you talking about the actual circuitry to shut down the coils. Or about the sensing mechanism that sees if it has fired. Like, making a program that shuts off the coils a few ms after you pressed the trigger shouldn't be hard. I am assuming that isn't what you are talking about.

>>4913 the circuitry and the sensors. I should have put PCBs instead of arduinos or pi's, I wasn't thinking too clearly.

You should just engineer a one-shot circuit. When triggered, it'll do everything necessary to launch. It should immediately shut down once the action is complete. Don't worry about "sensing" if the projectile left, just allow it to fail safe.

>>4926 got it and thank you.

>>4934 No problem buddy, good luck!

are these capacitor any good for this project?

>>4907 Can't you just use a timer circuit to switch the direction of the magnetic field in between shots?

>>5221 OMG!!! if I can put a casing around the coils and leave the part facing the barrel exposed then the only part of the field that would come into contact with the projectile is the side pushing it. like taking a coil off of a transformer is becomes a one way electro magnet.

>>4926 I was about to say the same >>4907 Any updates OP?

>>5533 yes, I'm gonna use threaded wire to make a single coil so the magnetic field goes one way and put a liquid nitrogen cooling system around the coil so it'll be a super conductor, I'm still doing testing though.

>>5653 For regular copper wires, you need liquid helium to achieve superconductivity.

>>5655 oh, thank you

update, I hate math and it's not going as planned at all. I chose the bifilar coil from tesla is going to require a board for each coil I have. I don't even have the blueprints yet.

>>6161 If you make a single-stage design, then you only need one coil to repel, and no switching. If you want to add multi-coils, synchronize the switching of the polarization of each coil according to a timer, set to when the projectile passes that coil. You can calculate when the projectile passes that coil using v_f^2 = v_i^2 + 2*a*d, where v_f = projectile final velocity, v_i = projectile initial velocity, a = projectile acceleration, d = barrel length

>>6163 is there a chip or componant I can use code on to achieve that? if not then single stage might in my best interest

>>4911 add a switch between your capacitors and your magnet array. Better yet, put a momentary button there, so the capacitors are only discharging while you holddown the button even one arduino is overkill for this.

>>6161 >update, I hate math and it's not going as planned at all. AFAIK the only electromagnetism you actually need to know to make a coil gun is pretty simple, OP. Watching a video youtube videos on the basis of induction and the electrical theory on coils should be enough. It also helps if you have a general intuitive knowledge of Maxwell's equations, but it's a bonus. What you need to understand is how coils create and react with magnetic flux and how magnetic circuits work (basically: air bad, iron good). >I chose the bifilar coil from tesla Interesting choice, but why? The one in your picture appears to me to be a parallel bifilar coil which is specifically designed to create no magnetic field (it's basically two coils in reverse which cancel each other out). Parallel bifilar coils could be used if you had two parallel but electrically isolated ones (not the case there) and use the primary to create the magnetic field to speed up the projectile and then using the secondary one to absorb that field. It's unclear to me why you wouldn't just do this with one coil, as is usually done. The usual way to drive this sort of big induction coil is to use a MOSFET (other transistor types are possible) and then a flyback diode: https://en.wikipedia.org/wiki/Flyback_diode As you know, it's impossible to instantly collapse the magnetic field of an inductor, inductors resist change in their current and magnetic field. So putting a diode across it allows it to reabsorb the magnetic field and waste it as resistive heat in the coil + diode across a relatively small period of time. It might be possible to decrease this period by applying a negative voltage to the coil? Not sure if anyone has done it or if it's worth the hassle. >is going to require a board for each coil I have. A 555 timer with a potentiometer for each of the stages should be all you need, idk why you'd require a microcontroller for each. If you do want to go the microcontroller route (which is perfectly reasonable, has plenty of pros to it) then you just need one digital output per stage to drive the corresponding MOSFET, no?

>>4907 Why would you not use a capacitor bank for the coil gun, or a mechanical switch?