int led = D2;
int switch = D3;
int lightPin = A3;
int lightNum = 0;
int ledBrightness = 0;

void setup() {
    pinMode(switchPin, INPUT_PULLUP);
    pinMode(led, OUTPUT);
    Particle.variable("light", lightNum);

}

void loop() {
    int buttonState = digitalRead(switch);
    
    if(buttonState == LOW){
        digitalWrite(led, HIGH);
        lightReading = analogRead(lightSensorPin);
        ledBrightness = map(lightReading, 4095, 2000, 0, 255);
        analogWrite(led, ledBrightness);
        delay(500);
    }
    else{
        digitalWrite(led, LOW);
    }
}