#include <stdio.h>
#include <string.h>
#include <avr/interrupt.h>
#include <avr/io.h>

#define LEDPIN 13
#define FOTOTRANSITORPIN 0 // fototransistor is on analog 0

void setup()
{
	analogReference(INTERNAL1V1);
	pinMode(LEDPIN, OUTPUT);
	Serial.begin(115200);
}

void loop(void)
{
	int n;
	int v;
	
	for (n = 0; n < 9; n++)
	{
		if (n == 8)
			analogWrite(LEDPIN, 255);
		else
			analogWrite(LEDPIN, 1 << n);
		Serial.print("n: ");
		Serial.print(n);
		Serial.print(", ");

		v = analogRead(FOTOTRANSITORPIN);
		Serial.print("v: ");
		Serial.println(v);
		delay(200);
	}
}