In this project, you're going to use additional ICs (Integrated Circuits) in the form of shift registers in order to drive LEDs to count in binary (I will explain what binary is soon). Specifically, you will drive eight LEDs independently using just three output pins from the Arduino.
|1 × 74HC595 Shift Register IC|
|8 × 220Ω Resistors*|
|8 × 5mm LEDs|
*or suitable equivalent ...