How to build at home a laterna magica or any other simple projector ?

Question

I need to have a description in detail .

Answer 1

You will need a box, a picture that light can pass through (transparent paint in the old style ones, or a film positive transparency), a mount to hold the picture, a screen, a rather bright light source, ideally with a reflector, and a more or less good lens. The smaller the source and larger image, the better the lens.
Mount the lens on one side of the box and cut 3 sides of a rectangle in an adjacent side to make a door. Inside the box mount the light (and reflector if you have one) at the other end of the box from the lens and facing it with the filament about even with the lens. Put the holder for the pictures between the light - ideally the holder should pretty much fill the box so it is divided into two parts, one with the light and the other with the lens. The picture should mount even with the lens. Darken the room, aim the box at the screen (or light colored wall), turn on the light and slide the holder back and forth trying to get the most focused picture you can. Close the access door, let your eyes accomodate to see the picture better. Keep one hand on the box to see if the light is making it too hot. If so, you may need to add ventilation.
How much of the image ends up on the screen and how big depends on the focal length of the lens and other stuff.

http://www.magiclantern14.btinternet.co.uk/Lanternintro.htm