Grove Ultrasonic not working properly?

Hi, I am currently doing a project about a human body thermometer. The sensor I am using is the grove ultrasonic sensor which is the same sensor with the HC-SR04 with less input pin needed (If I am not wrong) . The code I created is down below.

#include "Ultrasonic.h"
#include <Wire.h>
#include <Adafruit_MLX90614.h>
#include <LiquidCrystal_I2C.h>
Ultrasonic ultrasonic(7);
Adafruit_MLX90614 mlx = Adafruit_MLX90614();
LiquidCrystal_I2C lcd(0x27, 16, 2);
long range=200;

void setup() {
pinMode(9, OUTPUT);
int counter=0;
  if (range<=1){
    lcd.print("Body Temp:");
    tone(9, 500);
  range= ultrasonic.MeasureInCentimeters();

void loop() {

The sensor will suddenly pick up range<=1 without anything in its range and go in to the if section. Try to troubleshoot it by reading the value of range with a separate code but it never shows up to be 1 or less than 1. Is it the sensor is faulty or there is a bug/problem in my code?
Any help is appreciated, Thanks for helping!! :slight_smile:

Generally, you need to wait after reading an ultrasonic sensor, so that any echoes die away. Your code is pinging continuously.

If I rewrite the echo part of the code in the void loop instead with a delay under it does it make it better? Or generally is there another way of writing the code for ultrasonic sensor. I am quite new to Arduino so I am still not sure about how it works.

You can use what you have now. Just add a delay after (or before) you read the sensor.

Alright, Thanks for the Help!! Greatly appreciate it.

It seems to work fine now.

That's good. It's a common mistake to forget that the speed of sound is slow in this context compared to how fast an Arduino runs.