Fresner lense

I think its called. Basically a wide cone of mirrors like a satellite dish focussing the sunlight to a point and then you can use one of those cells that trun heat into elctricty and get free elctricty/ heat on every sunny day.

I think you may be thinking of a fresnel lens. It just a flattened lens.

How do you convert the heat into electricity? There are many ways, but just using a solar panel is the easiest for most people.

 yeah probably special solar panels to accept such intense light, but also, i saw a heat-into-elctricity cell. I don't know what it is called, but some one stuck some to an led flashlight so you could use your body heat to powere the flashlight.
HA - Thats how i used to think a light saber worked.
Its a flat (dull?) panel aobut an inch by three inches. I think they also make little units about the size of a bubba chewing gum, you can heat them up and they produce electricity.

yeah probably special solar panels to accept such intense light, but also, i saw a heat-into-elctricity cell. I don't know what it is called, but some one stuck some to an led flashlight so you could use your body heat to powere the flashlight.
HA - Thats how i used to think a light saber worked.
Its a flat (dull?) panel aobut an inch by three inches. I think they also make little units about the size of a bubba chewing gum, you can heat them up and they produce electricity.

I am not familiar with a small scale heat to electricity generators, but I am sure they are possible.
But you wont be able to produce more energy than you put in.

The whole human body generates about 60W worth of power, meaning if you could capture all of your heat into electricity it would run an incandescent bulb. Just your hands worth of heat would probably battle with anything but the smallest LED's
DEFINATELY wont power a light saber.

I semi-remember something called a *petzler* junction?

I semi-remember something called a *petzler* junction?

A Peltier Junction can move heat from one side to the other using power, or the reverse, generating power from a hot and cold side.

You need to have heat flow, so it's not as simple as heating it up. The other side needs to radiate the heat away faster than the input.

Even when you get it working it's very inefficient, used only to deal with waste heat that would otherwise be lost.

For small scales, solar panels are by far the best way to turn sunlight into electricity.