#include <TM1637Display.h>

#define CLK 2
#define DIO 3

TM1637Display display = TM1637Display(CLK, DIO);

void setup() {
  display.setBrightness(1);
  digitalWrite(12, HIGH);
}

void loop() {
  display.showNumberDec(1111);
  delay(1000);
  display.setBrightness(2);
  display.showNumberDec(1000);
  delay(1000);
  display.setBrightness(3);
  display.showNumberDec(1200);
  delay(1000);
  display.setBrightness(4);
  display.showNumberDec(1230);
  delay(1000);
  display.setBrightness(5);
  display.showNumberDec(1234);
  delay(1000);
}