Adjust contrast of Nokia 5110 LCD using ESP8266 NodeMCU board and a Potentiometer.

NodeMCU-ESP8266-Nokia-5110-LCD-Contrast.ino

#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>

#define analogPin A0 /* ESP8266 Analog Pin ADC0 = A0 */

/* Declare LCD object for SPI
 Adafruit_PCD8544(CLK,DIN,D/C,CE,RST);*/
Adafruit_PCD8544 display = Adafruit_PCD8544(14, 13, 5, 15, 4); /*D5, D7, D1, D8, D2 */
int contrastValue = 60; /* Default Contrast Value */

int adcValue = 0;  /* Variable to store Output of ADC */

void setup()
{
  /* Initialize the Display*/
  display.begin();

  /* Change the contrast using the following API*/
  display.setContrast(contrastValue);

  /* Clear the buffer */
  display.clearDisplay();
  display.display();
  delay(100);
  
  /* Now let us display some text */
  display.setTextColor(WHITE, BLACK);
  display.setTextSize(1);
  display.setCursor(15,1);
  display.println("|ESP8266|");
  display.setCursor(15,13);
  display.println("|NodeMCU|");
  //display.setTextSize(1);
  display.setTextColor(BLACK);
  display.setCursor(22,25);
  display.println("|Nokia|");
  display.setCursor(25,37);
  display.println("|5110|");
  display.display();
  //delay(2000);

}

void loop()
{
  adcValue = analogRead(analogPin);
  contrastValue = map(adcValue, 0, 1023, 0, 100);
  setContrast();
  //displayText();  
}


void setContrast()
{
  display.setContrast(contrastValue);
  display.display();
}