Step 1: WHAT YOU NEED
-1 bicycle innertube;
-piece of fleece.
Step 2: KNIT INNERTUBE
you should make a square piece of the mesurement of your telephone or i-pad.
I suggest to make the innertube thread really thin (2/3mm)'cause if not your case will become way too heavy and thick.
Step 3: CUT FABRIC
i used fleece cause is elastic, soft and the edges want unthread