Floating 3D Display Clock
Moritz v. Sivers' clock uses a beamsplitter and retroreflective foil to make digits float and rotate in midair.
Pixel displays can be interesting, but they tend to be 2D affairs. This clock by Moritz v. Sivers (AKA Twisted&Tinned) takes things into the third dimension with digits that appear to float and twist in space.
Each of the four digits is displayed on a fairly standard 8x8 LED matrix. However, instead of the user viewing time directly, each digit is turned into a 3D representation via a technique based on Aerial Imaging by Retro-Reflection (AIRR). To implement this AIRR effect, the device's enclosure positions a beamsplitter at an angle above the light source, and retroreflective material is added to the back of the 3D-printed case, parallel to the direction that the LEDs nominally face.
To further enhance the unit’s 3D effect, each matrix is turned using a servomotor, making the reflection appear to rotate in and out of plane. This makes a fantastic transition from one value to the next, shown in 2D — as well as 3D if you adjust your eyes properly — in the video below.
The clock uses a Wemos D1 mini ESP8266 board for overall control and wireless networking, along with a PCA9685 controller to interface with the servos. Build instructions can be found here, while code and STL files for printing are available on GitHub.
Once programmed, the device generates a Wi-Fi access point. This allows the user to enter local network credentials so that it can set the time via NTP.