Code a Mars Landing - Arduino

README.md

NASA Project website - Arduino Circuit

mars_hover.cpp

int distanceThreshold = 0;
int cm = 0;
int light;

int buttonState = 0;
int buttonAction = 0;
int buttonAction2 = 0;

long readUltrasonicDistance(int triggerPin, int echoPin) {
    pinMode(triggerPin, OUTPUT);
    digitalWrite(triggerPin, LOW);
    delayMicroseconds(2);

    digitalWrite(triggerPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(triggerPin, LOW);
    pinMode(echoPin, INPUT);

    return pulseIn(echoPin, HIGH);
}

void setup() {
    Serial.begin(9600);

    pinMode(2, OUTPUT);
    pinMode(3, OUTPUT);
    pinMode(4, OUTPUT);
    pinMode(8, OUTPUT);
    pinMode(12, INPUT);

  	char message[] = "Hover calling earth";
  
  	String output = "";
  	for (char messageChar : message) {
      	output += GetMorseChar(toLowerCase(messageChar));
  	}
  
  	Serial.println(output);
}

void loop() {
    // Button
    buttonState = digitalRead(12);

    // Light
    light = analogRead(5);

    // Sensor
    distanceThreshold = 30;

    cm = 0.01723 * readUltrasonicDistance(7, 6);

    Serial.print("Distance: ");
    Serial.print(cm);
    Serial.print(cm);
    Serial.print(" / ");
    Serial.print("Clarity: ");
    Serial.println(light);

    if (cm > distanceThreshold) {
        digitalWrite(2, HIGH);
        digitalWrite(3, LOW);
        digitalWrite(4, LOW);
    }

    if (cm < 20) {
        digitalWrite(2, HIGH);
        digitalWrite(3, HIGH);
        digitalWrite(4, LOW);
    }

    if (cm < 10) {
        tone(8, 68583572, 2000);
        digitalWrite(2, HIGH);
        digitalWrite(3, HIGH);
        digitalWrite(4, HIGH);
    }

    if (buttonAction == 1 && buttonAction2 == 0) {
      	buttonState = 1 - buttonState;
      	delay(20);
    }

    buttonAction2 = buttonAction;
    if(buttonState == 1) {
      	tone(8, 68583572, 2000);
    } else {
      	noTone(8);
    }

    delay(10);
}

String GetMorseChar(char tmpChar) {
	switch (tmpChar) {
        case 'a':	
			return ".-";
        case 'b':
            return "-...";
        case 'c':
          	return "-.-.";
        case 'd':
            return "-..";
        case 'e':
            return ".";
        case 'f':
            return "..-.";
        case 'g':
            return "--.";
        case 'h':
            return "....";
        case 'i':
            return "..";
        case 'j':
            return ".---";
        case 'k':
            return "-.-";
        case 'l':
            return ".-..";
        case 'm':
            return "--";
        case 'n':
            return "-.";
        case 'o':
            return "---";
        case 'p':
            return ".--.";
        case 'q':
            return "--.-";
        case 'r':
            return ".-.";
        case 's':
            return "...";
        case 't':
            return "-";
        case 'u':
            return "..-";
        case 'v':
            return "...-";
        case 'w':
            return ".--";
        case 'x':
            return "-..-";
        case 'y':
            return "-.--";
        case 'z':
            return "--..";
        default: 
            return " ";	
	}
}