18:21, 23/06/2024, Sunday

I feel like I already talked about this somewhere, but I don't really remember when/were...

I'm actually quite interested on starting a Hackaday project on making my own active camouflage, but I'm literally broke and I since I literally didn't even start making anything with my Mech/Exosuit project, I think I should just post the idea and let someone smarter (and more competent) than me to do the work.

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Not a super advanced technology:

DEPENDING on what you want with the final product, it really doesn't require a super advanced technology.

If you want something more akin to the Predator's or the Elites in Halo, then yes, it is impossible with our current technology.
Of course, there isn't a precise explanation for what they do, but it seems that they bend light around their body perfectly, being useful in any perspective and any distance.

And yes, point of view/perspective of the observer is a huge factor with these active camouflages:
If you look at a transparent camouflage like in the examples from the front with a wall in the back, they are perfect, but if simply walk around, you will see the distortions in background objects.

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What we can do:

Attach a bunch of cameras or colour sensors around a suit and a non-light display along it to either make a camouflage combining with the ambient or a straight up image of the surroundings.

A few examples: Octocamo from Metal Gear 4 and the Thermoptic Camouflage from Ghost In the Shell.

It uses colour sensors and flexible displays to blend in the background, and it can do it with multiple objects at the same time.

It also seems to use flexible peltier plates to change the heat in the surface to fool infrared cameras.

I don't know exactly how it works in ghost in the shell, but by the name, it is probably the same thing, but way more advanced.

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Real life technologies that could be used:

In the real world there also are those leticular lenses plastic panels that are normally used on holographic plates/tazos.

There are also electrochromic displays and electrowetting displays.

Posy made a really good video explaining the first:

This method doesn't need backlight and neither transmits light like LED pixels, which would be essential, or else you would be just a giant firefly in the night and a dim colour during the day.

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Now, to me, electrowetting is the most promising type of display for this type of optical active camouflage, it basically uses a similar methode to the e-paper, but using individual liquid pixels instead of a super complex paint with two polarities.

In simple terms, you have two electrodes separated by a dielectric material (insulator) where one of the electrodes is a droplet of liquid and the other electrode is just a conductive material (graphite, metal etc). When you add a charge to one of the electrodes, the droplet expands itself over the surface of the dielectric material, making a coloured pixel.

You can use these two examples as a possible way of making the pixels, you "just" need to add more layers with different colours and change the intensity of the charge and the quantity of pixels being activated to change colours.

There are entire displays out there that uses this technology, and since they don't emit light, but reflect it, they use a really small amount of energy.

But I do think you would need the back of all the pixels to be a frosted mirror, because these kinds of mirrors reflect the ambient light instead of a full on mirror.

I couldn't re-find the exact picture I had in mind, but a close thing is those diffusers for photography and movies:

In either way, electrowetting is not limited to ink pixels, but for some very specific applications, like microfluidic systems.

You could literally move droplets, and maybe, you could make a movable ink background for every colour.

However, if you can make a LED/light emitting pixels to match the exactly same lighting of the ambient, then you could just attach LEDs to a suit.

And finally, if you want to be extra super complex, but in a doable way, you could use expandable Voxels.
Literally inflating or vacuuming parts of the suit in order to change its surface texture, just like an octopus.

The closest thing I could find was this video/paper:

Maybe you could use printed very small HASEL actuators to make these inflation voxels and deflations instead of a super complex and intrinsic pneumatic system.

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You could use a mix of all of these characteristics to make an interesting active camouflage, and all of this is doable with todays technology.

The only problem would be if you wanted to make a really precise one at home, you would need to find a way of mass-producing these materials with a printer or something similar.

And depending on how you do it, you would need to find an transparent conductor for the background electrodes.

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About the heat camouflage:

Flexible Thermoelectric modules are normally made for very specific applications, like monitoring heat on a system or extracting body heat. But because of the seebeck/peltier effect, you can use them to turn electricity into heat.

There was one system in development for tanks that also used Peltier plates:

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The downsides:

Even if you are able to mass produce these Optical Active Camouflages with the most precise equipment and reduce the precise considerably, there are still some downsides that will be universal.

That is not saying the technology is not there yet, it is just that:

There isn't any system/machine/actuator/structure/material that doesn't have downsides, it is about trade-offs. You take the least worst option for your application and go with it.

• The durability:
  It would be the first problem, we are talking about possibly very sensible and delicate equipment here. Maybe a company/government/army can find a way of making these things last longer, but I'm not so sure when soldiers literally have to drag themselves on the ground to avoid being shot at.

• There is always a better scanner:
  Optical Active Camouflages would require to fool many different types of scanner systems at same time.
  There are multiple infrared spectrums that thermal cameras use, not to mention ultraviolet and radars.
  That's the reason why stealth aircraft is so fricking expensive and complex: they need to fool EVERY type of radar at the same time, and their biggest weakness is the infrared spectrum because of their combustion turbine (although you normally need to be very close to detect them like that, which would mean your d3ath).

• War is always distant:
  Although active camouflage would be very cool for individuals, it would still have a very niche application.
  Wars are fought by aircraft, missiles and sattelites, the active camouflage would only be useful for specific vehicles and special operations that need the soldiers to sneak in highly dangerous places.
  And even then, its effectiveness would be doubtful since you would still make a shadow in the ground (either from the sun or artificial lights).
  And even then, if you were able to make a super light that can mimic the ambient light to hidden your shadow, if anyone gets too close to you, they would definitely see you.

• WHY make it a DIY project?
  Even if you successfully make an Optical Active Camouflage at home, what would even be the point?
  Sure, people simply do it because it is cool, maybe for hunting, but heh. Wouldn't be cheaper to make a conventional one?

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Upsides:

However, although I'm very critical of this idea, I can totally see this being used in real life. A lot of armies, snipers and vehicles require visual camouflages to be continiously improved, repaired and changed.

Having an universal camouflage that would change whenever you want with a press of a button would definitely be an attractive idea, it could cut a lot of costs, or increase them.