Richard Clarkson made this lovely night light/speaker/hanging cloud and writes:

On one hand ‘Cloud’ is an Arduino controlled, motion triggered lightning & thunder performance. On the other it is a music activated visualizer & suspended speaker unit. The cloud is made by felting hypoallergenic fiberfill to a sponge casing which forms the frame of the cloud and holds the speakers and componentry. The felting tool used is a custom made felting tool made from the left over sponge and 4 felting needles. To control the functions of the cloud there are three tactile switches scattered around the base. The concept references real clouds which constantly change shape through the switches requiring constant exploration to find the right switch to turn the right feature on or off.

Richard used a Wave Shield, PIR motion sensor, yellow LEDs, white EL wire, and a few tactile on/off switches for this project. He even made his own yellow audio cable to look more like lightening connected to the bottom of the cloud.