This project uses a 555 timer IC and a 595 shift register IC to create an LED follower circuit. The 555 is setup as an astable circuit with the trim pot varying the frequency between 1.4 Hz to well over 100 Hz. The output from this circuit creates the clock pulses for the shift register. On the 595 shift register we feed the variable clock signal to both the shift clock input SCK and the register latch input RCK. This updates the outputs every clock cycle to create the follower movement in the LEDs. What is normally the serial data input SER is controlled by a momentary button pulling SER high when pressed. If the clock pulses while the button is pressed the high signal is latched to the output lighting up the first LED. The longer you hold the button down the more LEDs that light up as they follow up the line as they are shifted with each clock pulse. In normal (one shot) operation the lit LEDs shift to the top and disapear. If SW3 is in the repeat position the 8th LED state (high/low) is transmitted back to the SER input through a diode. This creates a repeating pattern. Because the shift register is 5 volt, I am powering the board via micro USB. I could only find that component with surface mount connections and the solder pads are really close together. It was a bear trying to solder them but I got it done with a lot of flux and some solder wick. This makes this board NOT beginner friendly.