Vermes
Advanced Member level 4
It is a RGB lamp. The pattern is displayed in multiplexed way. At one moment, only one level of the lamp (maximum 4x4x3 diodes) is lit. Each anode of the diode from each level is connected to the same line powered by buffer UDN2981A controlled by 48-bit register loaded in series (6x 74HCT595N). Cathodes of the diodes from each level are connected in one line. You can select the level by system ULN2803A. The main element of the system is Atmega32. The entire device requires seven lines to control so any other, smaller AVR can be used.
Pictures:
And the video:
Link to original thread (useful attachment) – Ledcube - rgb 4x4x4