/*
  *
  * Udemy.com
  * Building an Arduino DC Voltmeter
  *
  */
 
 float vPow = 4.7;
 float r1 = 68000;
 float r2 = 680000;
 int speed = 120;
 void setup() {
   
   pinMode(3, OUTPUT);
   analogWrite(3, speed);
  
   Serial.begin(9600);
   
   // Send ANSI terminal codes
   Serial.print("\x1B");
   Serial.print("[2J");
   Serial.print("\x1B");
   Serial.println("[H");
   // End ANSI terminal codes
   
   Serial.println("--------------------");
   Serial.println("DC VOLTMETER");
   Serial.print("Maximum Voltage: ");
   Serial.print((int)(vPow / (r2 / (r1 + r2))));
   Serial.println("V");
   Serial.println("--------------------");
   Serial.println("");
   
   delay(2000);
 }
 
 void loop() {
   float v = (analogRead(A0)* vPow) / 1024.0;
   float v2 = v / (r2 / (r1 + r2));
   
   // Send ANSI terminal codes
   //Serial.print("\x1B");
   //Serial.print("[1A ");
   // End ANSI terminal codes
   
   Serial.print(analogRead(A0));
   Serial.print(" ");
   Serial.println(v2);
   

    // First we check to see if incoming data is available:

    while (Serial.available() > 0)
    {
      // If it is, we'll use parseInt() to pull out any numbers:

      speed = Serial.parseInt();

      // Because analogWrite() only works with numbers from
      // 0 to 255, we'll be sure the input is in that range:

      speed = constrain(speed, 0, 255);

      // We'll print out a message to let you know that the
      // number was received:

      Serial.print("Setting speed to ");
      Serial.println(speed);

      // And finally, we'll set the speed of the motor!

      analogWrite(3, speed);
    }
  
   
 }