If you want to make a paper omnitrix, chances are you are familiar with the television show Ben 10. In this cartoon, Ben wears the omnitrix on his arm and uses it to change into different types of aliens. If you want to pretend to be Ben but don't want to spend a lot of money to buy a plastic omnitrix in the store, you can make a paper one with just a few materials.
Put your sheet of black construction paper in front of you so that the shorter side faces you. Measure up 4 inches from the bottom of the paper and draw a horizontal line. Cut along this line. Keep the smaller piece of paper and set aside the larger one. This is the armband on which your omnitrix will sit.
Take a lid from a pickle jar or jelly jar and place it on the table so that you are looking at the side with the printing on it. Lay the lid on top of the larger sheet of black paper and trace around it like a template. Cut out this black circle and glue it to the top of the lid.
Make a circle with the green paper that is exactly the same size as the black circle you just cut. Draw an hourglass shape on it.
Cut out the shape and discard the rest of the green paper. Glue it on top of the black circle. You have now made the default look for the omnitrix. Use the hot glue gun to attach the jar lid to the center of the arm band. You only need to glue it along the edges. Don't worry about the center.
Wrap the armband around your arm and mark the spot where one end of the paper overlaps the other. Glue your Velcro pieces onto the armband at this point so that you can put it on and remove it without tearing the paper.
Create additional discs for your omnitrix using the link in the resource section as a guide to what the alien images should look like. You can attach each disc to the default disc with invisible tape when you'd like to use it. Peel it off carefully.