ESP8266 Shift Register (74HC595) using the Arduino IDE and SPI

ESP8266-74HC595-SPI.ino

/* Example of using ES8266 with a 74HC595 shift register
** for more details, see http://42bots.com
--------------------------------------------------------
** Connections:
** ESP8266 GPIO13 to 74HC595 pin 14
** ESP8266 GPIO15 to 74HC595 pin 12
** ESP8266 GPIO14 to 74HC595 pin 11
** 74HC595 Vcc is connected to 3.3V
** 8 LEDs connected to the 8 outputs of the 74HC595
** via approariate velue resistor (I use 1k Ohm)
*/

#include <SPI.h>

int latchPin = 15; // pin D8 on NodeMCU boards
//int clockPin = 14; // pin D5 on NodeMCU boards
//int dataPin = 13; // pin D7 on NodeMCU
long randNumber;
 
void setup() 
{
  //set pins to output so you can control the shift register
  pinMode(latchPin, OUTPUT);
  //pinMode(clockPin, OUTPUT);
  //pinMode(dataPin, OUTPUT);
  SPI.begin();
  randomSeed(analogRead(A0));
}
 
void loop()
{
  randNumber = random(1, 255);
  // take the latchPin low so
  // the LEDs don't change while you're sending in bits:
  digitalWrite(latchPin, LOW);
  // shift out the bits:
  SPI.transfer(randNumber);
  //take the latch pin high so the LEDs will light up:
  digitalWrite(latchPin, HIGH);
  // pause before next value:
  delay(500);
}