Make: Projects

LED Shift Register

Blinking a line of six LEDs in bidirectional sequence.

  • By
  • Time Required: 4 hours
  • Difficulty: Moderate
LED Shift Register

The line of LEDs takes the inverted signals from a CD4017 counter, so that each LED generates light when the related outputs go to a low level. It works in bidirectional sequence. A 555 timer chip, in astable multivibrator mode, generates the clock signal.

Circuit schematic & video



Step #1:

LED Shift Register
  • The CD4017 integrated circuit may be damaged by static electricity.
  • Use an antistatic workbench.
  • Be connected to ground while you work.

Step #2:

LED Shift Register

If you connect the components with individual wires, I suggest that you start by soldering the wires on the integrated circuit's pins.

Step #3:

LED Shift Register
  • Check that the resistors' values work for your LEDs, especially on the middle stages.
  • Since your LEDs may be different from mine, you may have to modify the resistors' values.
  • Pay attention to the 470 and 47K resistors.