const float GAMMA = 0.7;
const float RL10 = 15;
int analogValue;
float voltage,resistance,lux;
const int relay1=04;
void setup() {
pinMode(relay1, OUTPUT);

}
void loop() {
analogValue = analogRead(A0);
voltage = analogValue / 1024. * 5; 
resistance = 2000 * voltage / (1 - voltage / 5);
lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
if(lux>=240){
digitalWrite(relay1, HIGH);
}else{
digitalWrite(relay1, LOW);
}
delay(500);
}