Voltmeter

voltmeter.ino

// Grove_4Digital_Display library
#include <TM1637.h>

int VREAD = 0;
int CLK = 8;
int DIO = 7;

float vout = 0.0;
float vin = 0.0;
float R1 = 100000.0;
float R2 = 10000.0;
int val = 0;

TM1637 TM(CLK, DIO);

void setup() {
  pinMode(VREAD, INPUT);
  TM.init();
  TM.set(2);
  TM.clearDisplay();
  TM.point(1);
  TM.display(0, 0);
  TM.display(1, 0);
  TM.display(2, 0);
  TM.display(3, 0);
}

void loop() {
  val = analogRead(VREAD);
  vout = (val * 5.0) / 1024.0;
  float curr = vout / (R2 / (R1 + R2));
  if (curr < 0.09) {
    curr = 0.0;
  }
  if (curr != vin) {
    vin = curr;
    int whole = vin;
    int dec = vin * 100 - (whole * 100);
    TM.clearDisplay();
    TM.point(1);
    TM.display(0, whole / 10);
    TM.display(1, whole % 10);
    TM.display(2, dec / 10);
    TM.display(3, dec % 10);
  }
  delay(500);
}