Using 2 Shift Registers(74HC595) to Drive 16 LEDs

This circuit will use 2 shift registers(74HC595) .The shift registers will drive as outputs 16 LEDs. Each shift register will drive 8 LEDs .The shift registers are wired so that each shift register outputs will look like a duplicate of the other.

Step 1: What Is a Shift Register?

Shift registers are sequential logic circuits.They are capable of storage and transfer of data.

Shift registers consist of many flip flops and clocks which are connected together .The outputs of the shift the shift registers are shifted or changed according to the clocks (pulsed outputs).

Step 2: Uses of Shift Registers

Shift registers are digital memory circuits used in calculators and computers .Shift registers can be used to expand the number of outputs from a microcontroller like Arduino.

Step 3: Electronic Components Used in the Circuit.

2 74HC595 shift registers

16 ;1 k resistors(brown,black,red)

16 LEDs

1 Arduino Uno

2 electrolytic capacitors ;10 Uf

2 long breadbaords

wires .

Step 4: Setting Up the Circuit

The outputs are Qa to Qh .Wire Qa first and then go to each other output as shown is the diagram.

pin14 is SER is connected to Arduino digital pin 11 .the SER is the DATA input which will be shift in.

Pin12 is RCLK (LATCH) is connected to

Arduino digital pin 8

Pin11 is SRCLK(CLOCK) is connected to Arduino digital pin 12

every time this pin goes high(1) the values in the shift register will shift by 1 bit .

Vcc is pin 16 is connected to the red breadboard rail

pin 8 is connected to ground

Arduino 5 volts is connected to the red rail of the breadboard

Arduino grounsd is connected to the black rail

Connect grounds of the boards together as shown is the diagram.

Step 5: How the Circuit Works

The 3 different inputs(CLOCK,LATCH,DATA) will change the voltages of the outputs as seen on the LEDs.The CODE will program the sequence of the LEDs and the speed of the LEDs turning on and off.