#define RELAY1_PIN 11
#define RELAY2_PIN 7

void setup() {
	// initialize serial communications at 9600 bps:
	Serial.begin(9600);

	pinMode(RELAY1_PIN, OUTPUT);
	pinMode(RELAY2_PIN, OUTPUT);

	digitalWrite(RELAY1_PIN, LOW);
	digitalWrite(RELAY2_PIN, LOW);
}

void loop() {
	digitalWrite(RELAY1_PIN, HIGH);
	delay(500);
	digitalWrite(RELAY2_PIN, HIGH);
	delay(500);
	digitalWrite(RELAY1_PIN, LOW);
	delay(500);
	digitalWrite(RELAY2_PIN, LOW);
	delay(500);
}