int pm=A2;
int led=6;
int state=0;
void setup() {
  // put your setup code here, to run once:
pinMode(pm, INPUT);
pinMode(led, OUTPUT);
Serial.begin(115200);
}

void loop() {
  // put your main code here, to run repeatedly:
state=analogRead(pm);
int bright=state/4;
if(state>0){
  Serial.print("pm=");
  Serial.print(state);
  Serial.print(" ; brightness=");
  Serial.println(bright);
analogWrite(6,bright);
}

}