Control a 10 LED Bar Graph with a 74HC595 shift register. The shift register needs just 3 wires to control 8 different outputs. Annoyingly, the LED bar has 10 different LEDs while the shift register has only 8 output pins. We solve this issue by doubling up the last 4 LEDs in the LED Bar graph. This way, the first 6 outputs of the shift register each control a single LED, while the last two outputs of the register control 2 LEDs each.