Play movies, cartoons, whatever on your ceiling using your phone.
Step 1: Items Needed:
fresnel lens sheet
Step 2: Figuring Distance:
Before cutting off the top of the gift bag, you will need to figure out the distance from phone to lens needed. In a dark room, place the phone on a flat surface where you wish to project the image. Keep in mind the further the distance from ceiling results in a larger but dimmer image. Hold the lense above the phone (with rough side of lense facing down) and find the focal point.
Step 3: Cutting Gift Bag:
Now that you have found the focal point, repeat the prior step with the gift bag next to phone and mark a line on the bag next to where the lense location is when focused on ceiling. Now cut the gift bag just above the line. If you cut at or below the line, you may never achieve a focused image.
Step 4: Almost There:
Place the phone in gift bag with phone on. Place the fresnel lens on top of the gift bag (rough side of lens facing down). If you cut the bag level then the lens should be level.
Step 5: Fine Tuning:
Remember how the bag was cut above the line. Well, the image is out of focus because of it. Remove the lens to place thin items under the phone until desired focus is reached.
Step 6: Video