Do all rear projection TVs have a fresnel lens? Update: Evil laugh!!!!

[SSSnail]

Maybe I should revive some of my childhood mischief and awaken... wait, that child in me never went anywhere...

Ooooh... candies!!!

 

[IronWing]

Maybe I should revive some of my childhood mischief and awaken... wait, that child in me never went anywhere...

Ooooh... candies!!!

Tonight, we're making smores!

 

[Pocatello]

Wow, I'm impressed.

 

[Red Squirrel]

Fun stuff. See if you can build a boiler and generate electricity with that. You would want to avoid complete focus though or you'd just melt the rad.

 

[phucheneh]

OP, you have access to a quality IR thermometer, by chance? I'm curious how hot that's actually getting.

Also, the problem with trying to generate electricity, or otherwise do work, aside from the general absurdity of the entire endeavor, would be moving the lens constantly. Perhaps you could design some kind of clockwork mechanism that you wind up in the morning, and the lens slowly moves over the course of the day (...in before the lens swings the wrong way and you light the moon on fire*).


(*this is sarcasm, if someone tries to 'educate' me on how far away the moon is and/or how lens focusing works I will slap them)

BTW, if anyone is curious: melting point of nickel is 2651* F, copper is 1984* F.

...holy fuckballs.

 

[PottedMeat]

Perhaps you could design some kind of clockwork mechanism that you wind up in the morning, and the lens slowly moves over the course of the day (...in before the lens swings the wrong way and you light the moon on fire*).

i bet it wouldn't be too hard to adapt one of those solar panel trackers for this



i see projection tvs out for cheap/for free all the time but i'm just too lazy to get it home

 

[IronWing]

I'm traveling for work now so no new videos/pics for a while. My wife melted down silver scrap yesterday. The borax flux is so bright under the lens that it is hard to look at even while wearing welding goggles. We also made smores.

 

[IronWing]

Melting asbestos tile

I checked the glass under a microsscope and confirmed that the asbestos fibers themselves melted. The asphalt binder vaporized and burned off.

 

[phucheneh]

Here's a thought...what about the small lens in the back of the TV that focuses the light from the bulb? Going with the whole TV-parts-in-reverse thing, could you put it under your fresnel lens and focus the light into a proper goddamned moon-laser? Or are you already past the melting point of the glass?

 

[Childs]

Try melting a mirror. 1 million views, guaranteed.

 

[oynaz]

The difference between knowing and understanding:

I knew there was a fresnel lens in projector TVs.

I didn't understand it until you turned one of them into a solar powered death ray.

 

[edro]

Can you look at the beam with your naked eye?
I would think the reflection off a nickel (or other semi-specular surface) would damage your eye.
Did you need sunglasses or welding glass?

 

[IronWing]

Can you look at the beam with your naked eye?
I would think the reflection off a nickel (or other semi-specular surface) would damage your eye.
Did you need sunglasses or welding glass?

Welding goggles are essential. I will need to buy a welding curtain if I decide to show it off in person. When cooking marshmallows, the reflection off the white surface is brighter than the sun.

 

[BladeVenom]

Try melting a mirror. 1 million views, guaranteed.

Why? It would melt eventually it would just take a lot longer.

 

[Childs]

Why? It would melt eventually it would just take a lot longer.

Would it? Or could you direct the beam somewhere else? Inquiring minds want to know...

 

[silverpig]

More videos:

Melting a nickel 1 (75% copper 25% nickel)

Melting a nickel 2

The camera is fine. One feature of solar concentrators that makes them easy to use but also dangerous is that outside of the focus spot there is very little heat. Stuff in the focus point can be burning or melting while the camera can be inches from the focus without harm.

It's not the heat... it's that the light is so bright you are saturating some of the pixels in the sensor and current is leaking through to other pixels. If you do this too much you can damage the sensor.

 

[BladeVenom]

Would it? Or could you direct the beam somewhere else? Inquiring minds want to know...

A mirror doesn't reflect all the light, so it would still get hot. I think a common plastic mirror would still absorb enough heat to start to melt and burn the plastic, and then it's reflectivity would be lost, and burn up like anything else. A high quality silver glass mirror would stand a better chance.

 

[Pulsar]

A mirror doesn't reflect all the light, so it would still get hot. I think a common plastic mirror would still absorb enough heat to start to melt and burn the plastic, and then it's reflectivity would be lost, and burn up like anything else. A high quality silver glass mirror would stand a better chance.

And in the mean time, if you were close, you could burn our your eyes! Bonus!

 

[mizzou]

http://www.youtube.com/watch?v=YoMjBkKOkPc

 

[mizzou]

hey, could you use this to smelt the gold flakes and silver from PC equipment?

 

[skyking]

liberating the good stuff from the really bad stuff is the problem.

 

[IronWing]

http://www.youtube.com/watch?v=YoMjBkKOkPc

Cool, but zinc fumes are really unpleasant.

 

[PlasmaBomb]

Welding goggles are essential. I will need to buy a welding curtain if I decide to show it off in person. When cooking marshmallows, the reflection off the white surface is brighter than the sun.

Good job IronWing

 

[IronWing]

So I made popcorn today. Only about half the kernels burned before they could pop. Not great but not horrible for a first try. Then I found this. I have been outclassed in every possible way.

 

[BladeVenom]

Then I found this. I have been outclassed in every possible way.

So you need 3 more lenses. Then you can turn all your useless sand into pottery.