#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
char line1[15] = "T=";
char line2[15];
char s[15];
double tt;
unsigned long ts,tb,tn;
long tm=0;

void setup() {
  Serial.begin(115200);
    lcd.init();
    lcd.backlight();
  ts = millis();
  tb=ts;
}

void loop() {
  if (millis() - ts >= 100) {
    ts=millis();
    tn=millis()-tb;
    tt = tn / 1000.0;
    dtostrf(tt, 3, 1, s);
    snprintf(line2, 15, "time: %s", s);
    //Serial.println(line2);

    lcd.setCursor(0, 0);
    lcd.print(line1);
    lcd.setCursor(0, 1);
    lcd.print("Time: "+String(tt,1));
    //lcd.print(tt,1);
  }
  tm++;
}