//
//       ATMEL ATTINY13 / ARDUINO
//
//                 +-\/-+
// ADC0 (D 5) PB5 1|    |8 Vcc
// ADC3 (D 3) PB3 2|    |7 PB2 (D 2) ADC1
// ADC2 (D 4) PB4 3|    |6 PB1 (D 1) PWM1
//            GND 4|    |5 PB0 (D 0) PWM0
//                 +----+


#define PIN_BTN		PB1
#define PIN_FAN		PB2
#define PIN_LED		PB3

#define FAN_OFF		0
#define FAN_LOW		1
#define FAN_MIDDLE	2
#define FAN_HIGH	3
#define FAN_FAST	4

static int fanSpeed;

void setup() {

	pinMode(PIN_BTN, INPUT_PULLUP);
	pinMode(PIN_FAN, OUTPUT);
	pinMode(PIN_LED, OUTPUT);

	fanSpeed = FAN_HIGH;
}

void loop() {

	if(digitalRead(PIN_BTN) == LOW) {
		while(digitalRead(PIN_BTN) == LOW);
		if(fanSpeed == FAN_OFF) fanSpeed = FAN_FAST; else fanSpeed--;
	}

	if(fanSpeed == FAN_FAST) {
		digitalWrite(PIN_LED, HIGH);
		digitalWrite(PIN_FAN, HIGH);
	}
	else if(fanSpeed == FAN_HIGH) {
		digitalWrite(PIN_LED, HIGH);
		digitalWrite(PIN_FAN, HIGH);
		delay(70);
		digitalWrite(PIN_FAN, LOW);
		delay(30);
	}
	else if(fanSpeed == FAN_MIDDLE) {
		digitalWrite(PIN_LED, HIGH);
		digitalWrite(PIN_FAN, HIGH);
		delay(50);
		digitalWrite(PIN_FAN, LOW);
		delay(50);
	}
	else if(fanSpeed == FAN_LOW) {
		digitalWrite(PIN_LED, HIGH);
		digitalWrite(PIN_FAN, HIGH);
		delay(30);
		digitalWrite(PIN_FAN, LOW);
		delay(70);
	}
	else {
		//FAN_OFF
		digitalWrite(PIN_LED, LOW);
		digitalWrite(PIN_FAN, LOW);
	}
}