“This circuit is made by applying very common CD4017 LED circuit so called as LED chaser.
But it can support diverse LED blinking methods by plugging control cables as different manners.
Maybe it can be utilized as bicycle backlight or visual indicator of Raspberry Pi or Arduino circuits.
This circuit is operating itself with own NE555 clock source without any control of external controller such as Raspberry Pi or Arduino.
It’s a very typical and common LED chaser circuit (Turning on LED on by one as sequential manner) using CD4017 (Decade Counter IC).
Therefore, detail explanations will not necessary for the circuit operation.
But some explanation is still necessary for the NE555 clocking circuit as it control blinking speed of LEDs.
The details are as described in the step next.”