Pretty Portable Projector!
Overview: We made a simple portable smartphone projector with relatively few materials. Device uses no electricity!
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Step 1: Gather Materials
-Shoebox painted black on the inside (or lined with black paper) -cardboard -convex lens -duct tape -scissors -smartphone -rubber band
Cut a hole in a small end of the shoebox. The hole should be the size of the lens.
Tape the edges of the lens to the hole in the box.
To make the phone fit snuggly in the box, tape pieces of cardboard to the inside of the box so that the cardboard and inner walls of the box hold the phone up.
Rubber bands may be taped onto the cardboard to serve as grippers.
In a dark room, try it out--you can adjust the image focus and size by changing the distance between the phone and the lens, and changing the distance between the box and the wall. Note: image on smartphone will be inverted. (Works well for pictures and video).
Step 7: Test Results
We found that it is extremely difficult to get a good image unless the test room is extremely dark and the projector is no farther than two meters from the wall. If the phone is 30 cm from the lens, then an image approximately 38 cm wide will be produced from a phone that is 8 cm wide. This is with brightness turned to the maximum. If smartphones were capable of getting even brighter, then this projector would be much more effective.
Step 8: Physics Explanation
The projected image was a real image. Light intersected on the opposite side of the lens from the smartphone. A convex (converging lens) is necessary for this project since it allows for light rays to meet on the opposite side.