The LED box is made from 3mm acrylic, with a front sheet of semi-transparent acrylic (WS10 / WS20). It is controlled by an Arduino Nano and contains a 5x5 LED matrix from WS2812 strips in the top part, a button to the left and an on-off switch. As a power source, we used a stripped usb cable that is connected to a standard mobile phone charger / powerbrick.
The front cover can be easily replaced. For the graphics on the front, we used a Plotter to cut out stickers (GCC Expert Pro).