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I’ve often thought it would be cool to mount a camera to a
ammo cartridge, that is, to take a tiny camera with an
onboard battery all mounted within a clear material and fix it
atop a reduced-power handgun or rifle cartridge. The camera
would be activated with a wireless signal and would stream
the video as it traveled down the barrel, through open space
and into whatever target or area designated by the shooter.
Obstacles might include transmission range, shock due to
acceleration and focus at speed, perhaps 700 - 1500 fps (200
- 450 mps).
Suspend the camera bits thusly
http://www.officepl...2hs0CFZJlfgodWaMGfw
Let the outer part of the bullet rotate separately [doctorremulac3, Jun 01 2016]
Just go with the whole spinning thing and design the optical elements around this idea
http://content.prov...oVideo/NIPKOWcc.jpg
[doctorremulac3, Jun 01 2016]
Spinning disk Microscopy.
http://zeiss-campus...k/introduction.html
[bs0u0155, Jun 01 2016]
I think this might do it
Level_20Flight_20Bullet
[doctorremulac3, Jun 04 2016]
Bullet cam
https://www.youtube...watch?v=hoGRlS53U_k
Nailed it! [whatrock, Apr 02 2017, last modified Mar 11 2020]
[link]
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It's been done with small-calibre artillery shells. The biggest problem is the spin intentionally induced by the rifling. Without the spin, the projectile wobbles in flight. |
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The solution is a FSDS round but that's not practical in a small-arms calibre, because it's basically a flechette. |
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A bazooka round sometimes doesn't spin (has fins), right?
Anything like that could maybe be used for this Idea (less
acceleration, too). |
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Yes, but that's a significantly different concept. Rockets like Javelin use fin stabilization... some have active guidance using steerable fins. Some MANPADS have IR sensor arrays, or crude imaging systems. |
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Active guidance on spin-stabilised projectiles is impossible using your species puny primitive technology. |
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Optical systems in freefall stores and missiles are Baked and WKTE. |
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You should post that, [IT]. |
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//The biggest problem is the spin intentionally
induced by the rifling. Without the spin, the
projectile wobbles in flight.// |
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Have the outer portion of the bullet spin while the
interior core where the camera is mounted stays in
one position. You'd need a practically frictionless
bearing for some spin to not be imparted to the core
but perhaps if the core was weighted at the bottom
and suspended at either end by magnets. (see link) |
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No, doesn't work. Active spin is unfeasable due to the available space. Spinning up the core using propellant gases is too erratic. The shock of firing disrupts any radial bearing through side-loading. Relying on gravity is ineffective, even if the gap between the core and the casing is evacuated, particularly if firing in the upper register. |
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What does sort of work is using a wide aperture and a very fast shutter speed and frame rate, then digitally recompose the video stream. But that takes quite a bit of processing so it's not real-time. And it tends to need a large CCD (which is difficult to shockproof) and an equally large lens. |
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Bear in mind that the space inside a 115mm shell is substantially smaller than its external dimensions suggest - the wall is very thick. |
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A 155mm projectile gives more scope for experimentation. |
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Have two outer shell sections, one in front of the other.
One spins at one speed with the rifling, the other having
little rubber wheels that are angled opposite the rifling
to
turn
the camera in the opposite direction. Then have a series
of gears that averages out the opposing spins and keeps
the center core in one place. |
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Of course the easiest way is to just design a camera that
takes its frames via a spinning wheel just like the first TV
camera / viewing sets did. (See link) Have the sensor
element on a very low friction bearing to that by the it
spins up to the speed of the surrounding bullet it's
already hit the target. |
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I think spin can be easily removed
electronically...same as electronic anti-shake
systems. But if the spin is too fast, then strobing the
CCD would be better. |
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Yea. It could be done, one way or another, electronically
obviously being preferable. |
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// I think spin can be easily removed electronically... // |
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Oh you do, do you ? Come on then Mr. Clever, cough up the details. |
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A lot of people have worked very, very hard on this problem and it's still very far from perfect; plus the unit failure rate on firing is unacceptably high. |
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// then strobing the CCD would be better. // |
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But there are limitations. |
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To get a clear image, the aperture time needs to be very short; given a typical rotational speed of 10000 RPM, that's 6 ms for one rotation - 1/166th of a second. So to capture an image at less than one degree of rotation, the "exposure time" is 16 microseconds - and you need very little aperture uncertainty to make that useful information. Since you're limited to ambient light (altho you can spread into the IR spectrum) you've got issues with illumination and sensetivity. |
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Blow-by into the tube, past the driving bands, contaminates the lens with smuts and propellant flakes, degrading the image quality further. |
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It's one thing to build a VT/prox fuse - quite another to deploy imaging technologies. |
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One useful approach is to use a modified smoke shell which ejects an instrumentation package on a 'chute at the top of its arc. Many seconds of telemetry are available while it drifts down, and a small self-destruct charge makes sure the opposition can't retrieve an intact unit. |
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Thing is, once you've shot the guy surely you can just
walk over and take a picture in the usual way? |
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You mean hand-colored black and white prints made with a pinhole camera? |
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//Of course the easiest way is to just design a camera
that takes its frames via a spinning wheel just like the
first TV camera / viewing sets did. (See link) Have the
sensor element on a very low friction bearing to that by
the it spins up to the speed of the surrounding bullet it's
already hit the target// |
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Damn you... I was gonna say that... actually imaging via
spinning stuff is baked tech. Take a look at the spinning
disk microscope. <link>. You can effectively multiplex
several Nipkow disks together. |
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I think the way to go would be something with more
manageable movement... a 40mm grenade? They spin at
10,000 rpm, same as a high end microscope arrange
photodiodes around the shell in several paralell spirals,
tune the separation to the approx spin rate and forward
speed, then have little lenses on each diode with
numerical appertures tuned to the inter-photodiode
distance and there you go... a Petran cylinder spinning-
chip macroscope. Give me 1 bajillion dollars and a team
of experts and I'll attempt to develop it for you. |
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You'll just have to hope Donald T. wins the election and makes some complete goofball Sec. Of Defense. |
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While you're developing the system, any chance you can call forth some spirits fom the vasty deep, too ? That's a trick we'd certainly pay a dollar to see. |
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// very low friction bearing // |
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.... that will withstand 5000g+ of linear acceleration, and an equally sharp spinup from rest to 10000RPM in a rather short time... |
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// call forth some spirits // |
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I know where you can obtain some high proof Cat Gin... |
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//Give me 1 bajillion dollars and a team of experts and I'll
attempt to develop it for you.// |
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I'll do it for half a bajillion. |
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Couldn't you just have every-so-many rounds equipped only with imaging tech and deployable fins to slow rate of rotation? |
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Sure the imaging-rounds won't track as far but you'd get a very clear view of the shots in front... and probably of several shots behind as they go racing past at a slightly higher elevation.
A pinch of phosphorous in the leading shells, or infra-red imaging and Roberts' your mums bro. |
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Possibly the bullet (clear thingy containing the payload) could
be rather long with everything wedged into the front portion,
leaving the rear 2/3 basically empty and therefore lighter.
Launched from a smooth bore to reduce spin, the weight
forward would keep the camera pointed towards the action
while the lighter rear portion added stabilization. |
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// Oh you do, do you ? Come on then Mr. Clever,
cough up the details. // |
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The margin over there -> does seem to be incredibly
small. <runs away> |
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You can run, but you can't hide. |
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// smooth bore to reduce spin // |
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... which means it will wobble, and quite possibly tumble. Without fins, it will be very unstable. |
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It is possible to deploy fins post-firing and they're quite effective, but again that's FSDS. |
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Mortar rounds, which are fin-stabilised, can also be used - but the range is limited compared to an artillery round. |
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The idea restricts usage to frivolity: the actual Idea would be to fire the bullet into the air, deploying a parachute at zenith, then transmitting back to a smartphone or something. |
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I think I might have solved the problem. See link. |
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Keeping a projectile from spinning isn't such a silly
quest. In the age of smart munitions, having a
camera or other sensory / guidance system on board
that's operating from a stable platform would be very
useful and eliminate a lot of problems. I think my
solution might work. |
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// Roberts' your mums bro // |
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Translation: More than one mum of yours performs bro-ing,
and this process belongs to more than one Robert. |
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// ... which means it will wobble, and quite possibly
tumble. Without fins, it will be very unstable. // |
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No, because it was specified that it would be ballistically
stable (in the same way as a model rocket). |
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The imagery isn't as good as the video suggests, and you need really strong ambient light for acceptable results. They work, sort of. Something better will no doubt be developed in time. They claim they rounds are a ballistic match with regular FMJ, but they aren't, there's a lot of drift and variation. |
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// And... baked. (link)// - Just as long as everyone
realises that was an April Fool's joke. |
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Still not sure what advantage you get from the camera-
tipped bullet, that isn't far better served by loitering spy
munitions or passively guided projectiles - all of which
already exist or are being worked on. |
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Cool vid (updated)... but is it fantasy or baked? |
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[8th], did you have to do this ? |
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" You'll just have to hope Donald T. wins the election and makes some complete goofball Sec. Of Defense. " |
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