The Cat book cover prototype meows when it detects strong magnetic fields nearby. It was designed by Japanese designer Rikako Sakai for people who are always stressed out and use mobile phones and email very often. You can wrap your agenda or a sketchbook in this cover and each time you receive or send messages through wireless devices, it meows to let you know about these invisible activities in a less intrusive way.
Cat cover is made of an electromagnetic waves sensor, a microchip, a sound card, four button sized batteries, and a speaker.