The control unit is assembled from five boards - three blinker key boards at the bottom and two control boards at the top, installed one above the other like a sandwich:

The purpose of the board is to switch of individual blinkers. Each board contains 14 optotriacs controlled by two shift registers. The shift registers of the three boards are chained, allowing up to 42 outputs to be controlled. Since the number of flip-dots on each digit block is only 35; seven outputs on the bottom board are not used.

The main board is a heard of the control module. It contains a Arduino Nano board and two polarity switches. Most of the panel is occupied by connectors linked it to key boards and blinker blocks

To set the time and date, a button module based on TM1638 was used