#include <math.h>
const int ledPin=4;
  //Connect the LED Grove module to Pin4, Digital 4
const int thresholdvalue=50;
  //The threshold for which the LED should turn on.
float Rsensor; //Resistance of sensor in K
 
void setup() {
 pinMode(ledPin,OUTPUT); //Set the LED on Digital 4 as an OUTPUT
}
 
void loop() {
 int sensorValue = analogRead(0);
 Rsensor=(float)(1023-sensorValue)*10/sensorValue; 
 if(Rsensor>thresholdvalue)
 {
  digitalWrite(ledPin,HIGH);
 }
 else
 {
  digitalWrite(ledPin,LOW);
 }
}