Who wouldn’t like to have a crystal ball? Unfortunately, our computers aren’t very good at predicting the future. However they do occasionally get the weather correct, so [Jenny Hanell] built a crystal ball to show the weather forecast. She calls it “Sphaera” and you can see a video of it in operation below.
The user interface is entertaining, and relies on 5 photoresistors. The Raspberry Pi inside detects when you cover one of them up, and interprets that as a command. A piece of plastic allows for projection inside the sphere from an LCD display. [Jenny] calls that a hologram although technically it isn’t a true hologram, of course.