Picture of 74HC595 digital LED Display Based on Arduino( Code Provided)
The Chief Engineer of  ICStation R&D department Jack is using ICStation UNO R3 compatible with Arduino to successfully make the 74HC595 drive four digital LED display. We will share the schematic diagram, wiring diagram,making steps,download Diagram and  also the useful program code designed by ICStation.

When you develop a project, it often needs to make IO expansion.The 74HC595 shifting register is a good choice. Following will introduce you that use two pieces 74HC595 to realize the display system of four digital LED(of course, can also realize 8 digital LED display) .It only uses three IO (PIN2,3, 5) of Arduino.

Components list:
1. ICStation UNO development board  $12.69 ( Or Arduino UNO development board)
2.2PCS 74HC595
3.DuPont line: 30PCS
4.four digital LED display with the same anode
5. 20 PCS 20mm pin header
6.Bread board
7.USB Cable
8.4PCS 47Ω resistance

Step 1: Schematic diagram

Picture of Schematic diagram
dancopy1 year ago

Hi Friend! the following error appears:
'sclr' was not declared in this scope
Thank you

dqxt1 year ago

the code 'pinMode(sclr, OUTPUT); ' must be commented.

it is better to use 'ShitOut()' function.

ICStation (author)  dqxt1 year ago

Thank you for your valuable advice!

The following is the code that has been changed.


#define HC_DATA_H digitalWrite(data, HIGH) // data line output high
#define HC_DATA_L digitalWrite(data, LOW) //date line output low
#define HC_RCK_H digitalWrite(rck, HIGH) // rck output high
#define HC_RCK_L digitalWrite(rck, LOW) // rck output low
#define HC_SCK_H digitalWrite(sck, HIGH) // sck output high
#define HC_SCK_L digitalWrite(sck, LOW) // sck output low

unsigned char LED_BCD[16] ={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e }; //common anode digital tube BCD code
//Define the pin
int data =2;
int rck =3;
int sck =5;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(data, OUTPUT); //initial data
pinMode(rck, OUTPUT); //initial rck
pinMode(sck, OUTPUT); //initial sck
pinMode(sclr, OUTPUT); //initial sclr


// the loop routine runs over and over again forever:
void loop() {

unsigned char dopp =0;
for( unsigned char i=0; i < 4; ++i)
if(i ==3) dopp =1;
else dopp =0;
LED_display(i,i,dopp); //Nixie Tube display


void LED_display(char LED_number,unsigned char LED_display,unsigned char LED_dp)
// data analyse
unsigned int hc_disp = 0,hc_ledcode,hc_ledcode_temp=0;

if(LED_display > 15) LED_display = 0;
hc_ledcode = LED_BCD[LED_display] ; //get BCD code
for(unsigned char i=0; i < 8;++i)
hc_ledcode_temp <<=1;
if(hc_ledcode&0x01) hc_ledcode_temp |= 0x01;
hc_ledcode >>=1;

if(LED_dp) hc_ledcode_temp &= 0xfe;
hc_disp = hc_ledcode_temp;

case 0: hc_disp |= 0x8000;break;
case 1: hc_disp |= 0x4000;break;
case 2: hc_disp |= 0x2000;break;
case 3: hc_disp |= 0x1000;break;

write_74HC595_ShiftOUTPUT(hc_disp); //74HC595 shifting register data transfer


//shift output to 74HC595
void write_74HC595_ShiftOUTPUT( unsigned int data_a) //communication with 74HC595
char look =0;
HC_RCK_L; //latch open

for (;look < 16; ++look)
if(data_a&0x0001) {HC_DATA_H;}
else {HC_DATA_L;}

data_a >>= 1;