That’s a ton of juice. Where’s all the energy getting lost? Friction?doc_loliday wrote: ↑Fri Apr 09, 2021 2:42 pmIt couldn't do that. I'd need a lot more capacitors for that. Those 5 caps, each at 4300uF, and you may be thinking that's enormous, and it is, at 350V that's nearly 1300J. But coil guns/rail guns are fantastically inefficient, less than 1%. In fact mine was only 0.1886%. Also, they are really dangerous. This thing already delivers a maximum of around 1000 amps. Although that's enough to kill a battalion and then some, I guess it doesn't really matter if it were 100 times more powerful.
2nd Amendment Thread
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Re: 2nd Amendment Thread
No, theres no friction. The slug travels through the center of the coil, it doesnt touch anything. I mean there is tiny bit of friction to be overcome "pulling" the slug out of the holding rod, but it's basically negligible. The losses come generating the magnetic field. It takes are very large magnetic field to move something that big, that fast. The magnetic reluctance of air is very high, so it takes a lot of energy to overcome that and then the slug only physically occupies a small amount of space in that field. Most of the energy does not get applied to the slug.SuburbanFarmer wrote: ↑ That’s a ton of juice. Where’s all the energy getting lost? Friction?
I could make mine quite a bit more efficient actually, by redesigning the coil. Also capacitors aren't the best way to generate a large current. They're just the easiest. I could do timed multistages or a pulse forming network.
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Re: 2nd Amendment Thread
The new Head of Engineering on the Woke Ark.
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Re: 2nd Amendment Thread
I remember somewhere (got to dig it up) creating a tracking system that would recognize anything over a specific size as a "threat" so cats, dogs, etc... wouldn't be an issue. Anything human size would be "shot at" with "airsoft pellets"doc_loliday wrote: ↑Fri Apr 09, 2021 2:19 pmThe Conservative wrote: ↑Fri Apr 09, 2021 1:32 pmLaser tracking? give me a rail gun! Although that tracking system is cool... what did you use to make it track?
The rail gun is considerably more difficult to construct. The resistance between the slug and the rails has to be extremely small, fractions of an ohm. Adding weight to increase the contact, for example, is problematic for a few obvious reasons. Another problem is the cost of the materials, every time I had a bad go, I was blowing chunks of aluminum out of my rails. I could go for better materials, but I decided to dedicate my efforts to the coil gun since there is no sliding friction. Additionally, I would have had to construct a bigger better turret, with bigger motors, so its kind of on the shelf at the moment. I will say that the physics for modeling the rail gun are a bit simpler and there is better documentation. Also, I will mention that I've seen a few videos where people cobble together these things, but mine is engineered, ie, I started with the physics equations, and there are a lot, and wrote a long ass script to model the physics of the coil gun. In fact, that part took me the longest out of everything, and the compile times took hours. But it actually works. I have confirmed my results empirically by measuring the muzzle velocity of the slug and the distance it travels, etc.
Anyway regarding the tracking. It's pretty humble, but it works. Essentially I continually take pictures, filter out the color I want, and apply a sizing threshold. I do the same for the laser. Then I use trigonometry to find the distances and angles and then coordinates. I send those coordinates to a microcontroller which calculates how much to move the stepper motors and moves them. If your'e interested I can go into more detail. One issue though is that, the object has to stop momentarily, since there is no predictive algorithm, the gun is always just a tiny bit behind.
Actually the better move would be to use kalman filters, which is pretty standard object tracking, but very robust, space program/military controls use them, but I've never actually done that before, and the aforementioned is something I was just able to come up with without too much thought.
They said they would introduce the code to the public, I don't know if they ever did, but if I can find it, I'll post a link again.
I like the idea of a coil gun, how many shots can you get before you need to recharge those things? BTW those are massive... I wouldn't want to be on the receiving end of those if they rupture.
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Re: 2nd Amendment Thread
Motion tracking is well described, you can find a lot of videos on youtube with explanation and code.The Conservative wrote: ↑Sat Apr 10, 2021 6:09 amI remember somewhere (got to dig it up) creating a tracking system that would recognize anything over a specific size as a "threat" so cats, dogs, etc... wouldn't be an issue. Anything human size would be "shot at" with "airsoft pellets"
They said they would introduce the code to the public, I don't know if they ever did, but if I can find it, I'll post a link again.
I like the idea of a coil gun, how many shots can you get before you need to recharge those things? BTW those are massive... I wouldn't want to be on the receiving end of those if they rupture.
With this coil gun, you get one shot per charge. Charging time is about 1 minute. This could be improved, but I'd need higher power boost converter. Mine can handle about 40W, but it gets pretty hot there, so I made sure it didn't exceed 35. The charging power supply shown on the left was set to around 35V, so I had to limit the current to 50mA. That's what those decade boxes are for. Since the capacitors become more difficult to charge over time, I decreased the resistance of the decade boxes to keep that output current steady.
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Re: 2nd Amendment Thread
PLATA O PLOMO
Don't fear authority, Fear Obedience
Don't fear authority, Fear Obedience
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Gun control is a lost cause. Come despair with me........ USA Today
https://www.usatoday.com/story/opinion/ ... 279107002/
https://www.usatoday.com/story/opinion/ ... 279107002/
PLATA O PLOMO
Don't fear authority, Fear Obedience
Don't fear authority, Fear Obedience
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Re: 2nd Amendment Thread
Crack a cold one boys
Supreme Court rules warrantless home gun confiscation is unconstitutional in 9-0 vote
https://americanmilitarynews.com/2021/0 ... -9-0-vote/
Supreme Court rules warrantless home gun confiscation is unconstitutional in 9-0 vote
https://americanmilitarynews.com/2021/0 ... -9-0-vote/
PLATA O PLOMO
Don't fear authority, Fear Obedience
Don't fear authority, Fear Obedience
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Re: 2nd Amendment Thread
Oh do tell.The very core of the Fourth Amendment,” Thomas wrote, is the “right of a man to retreat into his own home and there be free from unreasonable search and seizure.”