/*
  GARRF Virtual Engineering Laboratory
  EXPERIMENT 01
  Ohm's Law & Virtual Electronics

  Developed by:
  Dr. Annamdas Venu Gopal Madhav
  and
  Shantanu Vasudev Krishna Annamdas

  Product of GARRF
*/

const int POT_PIN = A0;
const int LED_PIN = 9;

const float SUPPLY_VOLTAGE = 5.0;
const float RESISTANCE_OHMS = 220.0;

void setup() {

  pinMode(LED_PIN, OUTPUT);

  Serial.begin(115200);

  Serial.println();
  Serial.println("======================================");
  Serial.println(" GARRF VIRTUAL ENGINEERING LAB");
  Serial.println(" EXPERIMENT 01 - OHM'S LAW");
  Serial.println("======================================");
  Serial.println();

  Serial.println("Turn the virtual potentiometer.");
  Serial.println("Observe Voltage, Current and Resistance.");
  Serial.println();
}

void loop() {

  int adcValue = analogRead(POT_PIN);

  /*
     Convert ADC reading to voltage.
     Arduino UNO ADC = 10 bit = 0..1023
     Reference voltage = 5V
  */

  float voltage =
      (adcValue / 1023.0) * SUPPLY_VOLTAGE;

  /*
     For teaching purposes we treat the
     220-ohm resistor as the load.
  */

  float current =
      voltage / RESISTANCE_OHMS;

  float current_mA =
      current * 1000.0;

  /*
     LED brightness changes with the
     potentiometer setting.
  */

  int brightness =
      map(adcValue, 0, 1023, 0, 255);

  analogWrite(LED_PIN, brightness);

  Serial.println("--------------------------------------");

  Serial.print("ADC Value       : ");
  Serial.println(adcValue);

  Serial.print("Voltage         : ");
  Serial.print(voltage, 3);
  Serial.println(" V");

  Serial.print("Resistance      : ");
  Serial.print(RESISTANCE_OHMS, 1);
  Serial.println(" ohm");

  Serial.print("Calculated I    : ");
  Serial.print(current_mA, 3);
  Serial.println(" mA");

  Serial.print("Ohm's Law Check : V = I x R = ");

  Serial.print(current, 5);
  Serial.print(" x ");
  Serial.print(RESISTANCE_OHMS, 1);
  Serial.print(" = ");

  Serial.print(current * RESISTANCE_OHMS, 3);
  Serial.println(" V");

  delay(1000);
}