Digital voltmeter for dc power bench

example code

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2CL lcd(0x3F,2,1,0,4,5,6,7);

void setup()

{

  lcd.begin (16,2); 

  lcd.setBacklightPin(3,POSITIVE);

  lcd.setBacklight(HIGH);

  

  lcd.print("this is really  ");  

  lcd.setCursor ( 0, 2 );

  lcd.print ("simple!! right ?"); 

}

void loop()

{

}

Digital voltmeter code

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x3F,2,1,0,4,5,6,7); 

int analogInput = 2;

float vout = 0.0;

float vin = 0.0;

float R1 = 100000.2; // resistance of R1 (100K) -see text!

float R2 = 10000.2; // resistance of R2 (10K) - see text!

int value = 0;

void setup(){

   lcd.begin (16,2); // for 16 x 2 LCD module

  lcd.setBacklightPin(3,POSITIVE);

  lcd.setBacklight(HIGH);

   pinMode(analogInput, INPUT);

   lcd.begin(16, 2);

   lcd.print("NOW VOLT");

}

void loop(){

   // read the value at analog input

   value = analogRead(analogInput);

   vout = (value * 5.0) / 1024.0; // see text

   vin = vout / (R2/(R1+R2)); 

   if (vin<0.09) {

   vin=0.0;//statement to quash undesired reading !

} 

lcd.setCursor(0, 1);

lcd.print("INPUT V= ");

lcd.print(vin);

delay(500);

}

Diagram

video link