So what can you do with your older smartphones? You can always try to turn them into interactive butterflies like the good people at isthis.gd. When you phone a butterfly, it comes to life with movement and light, with the pattern on its wings generated from your phone number.
As MAKE explains, these butterflies were made with recycled phone parts. Raspberry Pi units where used to generate the patterns. Each Pi controls 4 phones and handles the motors and lights. The first digit of your phone number determines color, second is used for speed, and so forth. Pretty cool if you ask us.[Source]